Vanessa cardui is the most widespread of all butterfly species. It is commonly called the painted lady, or formerly in North America the cosmopolitan.

 

Description

For a key to the terms used, see Glossary of entomology terms.

See also: Cynthia (butterfly) § Distinguishing features

 

Wing scales.

Male and female. Upperside. Ground-colour reddish-ochreous, basal areas olivescent-ochreous-brown; cilia black, alternated with white, Forewing with an outwardly-oblique black irregular-shaped broken band crossing from middle of the cell to the disc above the submedian vein; the apical area from end of cell and the exterior border also black; before the apex is a short white outwardly-oblique streak and a curved row of four round spots, the second and third being small; a marginal pale lunular line with its upper portion most defined and whitish. Hind-wing with a blackish patch from the costal vein across end of cell, a partly confluent recurved discal band, a submarginal row of lunules, and then a marginal row of somewhat scutiform spots; between the discal band and submarginal lunules is a row of five round black spots, which in some examples show a pale and dark outer ring. Underside. Forewing brighter reddish-ochreous, the apical area and outer margin much paler, the apex being olivescent ochreous-brown; discal irregular band as above, subapical white streak, row of spots and marginal lunules distinct; base of wing and interspace before end of cell white. Hindwing transversely-marbled with olivescent ochreous-brown and speckled with black scales; crossed by basal and discal sinuous whitish or pale fascia and intersected by white veins; an outer-discal row of five ocelli, the upper one smallest and usually imperfect, the second and fifth the largest, the fourth with black centre speckled with blue and ringed with yellow, and the second and fifth also with an outer black ring; submarginal lunules purpurescent-grey, bordered by a whitish fascia; outer margin ochreous. Body olivescent ochreous-brown, abdomen with ochreous bands; palpi blackish above, white beneath; body beneath and legs greyish-white; antennae black above, tip and beneath reddish.

 

Distribution

V. cardui is one of the most widespread of all butterflies, found on every continent except Antarctica and South America. In Australia, V. cardui has a limited range around Bunbury, Fremantle, and Rottnest Island. However, its close relative, the Australian painted lady (V. kershawi, sometimes considered a subspecies) ranges over half the continent. Other closely related species are the American painted lady (V. virginiensis) and the West Coast lady (V. annabella).

 

Migration

V. cardui occurs in any temperate zone, including mountains in the tropics. The species is resident only in warmer areas, but migrates in spring, and sometimes again in autumn. It migrates from North Africa and the Mediterranean to Britain and Europe in May and June, occasionally reaching Iceland,[8] and from the Red Sea basin, via Israel and Cyprus, to Turkey in March and April. The occasional autumn migration made by V. cardui is likely for the inspection of resource changes; it consists of a round trip from Europe to Africa.

 

For decades, naturalists have debated whether the offspring of these immigrants ever make a southwards return migration. Research suggests that British painted ladies do undertake an autumn migration, making 14,500 km (9,000 mi) round trip from tropical Africa to the Arctic Circle in a series of steps by up to six successive generations. The Radar Entomology Unit at Rothamsted Research provided evidence that autumn migrations take place at high altitude, which explains why these migrations are seldom witnessed. In recent years, thanks to the activity of The Worldwide Painted Lady Migration citizen science project, led by the Barcelona-based Institute of Evolutionary Biology (Catalan: Institut de Biologia Evolutiva), the huge range of migration has begun to be revealed. For example, some butterflies migrated from Iceland to the Sahara desert, and even further south.

 

V. cardui is known for its distinct migratory behaviour. In California, they are usually seen flying from north to north-west. These migrations appear to be partially initiated by heavy winter rains in the desert where rainfall controls the growth of larval food plants. In March 2019, after heavy rain produced an abundance of vegetation in the deserts, Southern California saw these butterflies migrating by the millions across the state.

 

Similarly, heavier than usual rain during the 2018-2019 winter seems to have been the cause of the extraordinarily large migration observed in Israel at the end of March, estimated at a billion individual butterflies. Painted lady migration patterns are highly erratic and they do not migrate every year. Some evidence suggests that global climatic events, such as el Niño, may affect the migratory behaviour of the painted lady butterflies, causing large-scale migrations. The first noticeable wave of migration in eastern Ukraine was noted in the 20s of April 2019. From May 15, numbers began to grow and it was possible to observe hundreds of this species in the Kharkiv region of Ukraine, including in the city streets of Kharkiv.

 

Based on experimental data, the painted lady's migration pattern in northern Europe apparently does not follow a strict north-west heading. The range of headings suggests that migrating butterflies may adjust their migration patterns in response to local topographical features and weather, such as strong wind patterns. Laboratory-raised autumn-generation painted lady butterflies were able to distinguish a southern orientation for a return migration path. According to the same laboratory-based study, when butterflies were isolated from the sun, they were unable to orient themselves in a specific direction, opposed to those that did have access to the sun. This suggests that V. cardui requires a direct view of the sky, implying the use of a solar compass to orient its migratory direction and maintain a straight flight path.

 

Mating behaviour in relation to migration

V. cardui displays a unique system of continuous mating, throughout all seasons, including the winter. This may be attributed to its migratory patterns, thus significantly affecting its mating behaviour. During European migrations, the butterflies immediately begin to mate and lay eggs upon arrival in the Mediterranean in the spring, starting in late May. In the United States, painted lady butterflies migrating towards the north experience poor mating conditions, and many butterflies have limited breeding capabilities. The "local adult generation" develops during this time, roughly from the middle of May through early June in conjunction with the butterfly progression throughout their flight.

 

During its migratory process, these painted lady butterflies start breeding, and reproduce entirely throughout their migration. Scientists have not been able to find evidence of their overwintering; this may be because they migrate to warmer locations to survive and reproduce. Female painted lady butterflies may suspend their flight temporarily when they are "ready to oviposit"; this allows them the opportunity to continually reproduce throughout their migrations. Because these butterflies are constantly migrating, male butterflies are thought to lack consistent territory. Instead of requiring territory to mate with females and developing evolutionary behaviour to defend this territory, the mating butterflies appear to establish a particular "time and place" in certain locations that they find to be suitable for reproduction. More specifically, they locate certain perches, hilltops, forest-meadow edges, or other landmarks where they will stay until, presumably, a female arrives to mate.

 

Equally important for the reproduction of the painted lady butterflies is the males' exhibition of polygynous mating behaviour, in which they often mate with more than one female. This is important for painted lady butterflies because the benefits may supersede the costs of polygyny since no permanent breeding ground is used. Upon mating, which typically occurs in the afternoon, female painted lady butterflies lay eggs one by one in their desired breeding locations. The variety of eclosion locations ultimately dictates the male painted lady behaviour.

 

Female painted lady butterflies have been observed to have a relatively "high biotic potential", meaning they each produce large numbers of offspring. This perpetual influx of reproduction may be a reason why these painted lady butterflies have propagated so successfully. One interesting aspect that scientists have observed is that these butterflies like to fly towards rain. Further studies have suggested that the large amounts of rainfall may somehow "activate more eggs or induce better larval development". Inhabited locations begin to observe a large influx of new generations of painted lady butterflies in the fall, particularly in September and October. Their reproductive success declines relatively throughout the winter, primarily through November. However, they still continue to reproduce—an aspect of butterfly behaviour that is quite unique. Scientists hypothesize that these extensive migratory patterns help the painted lady butterflies find suitable conditions for breeding, thus offering a possible reason as to why these butterflies mate continuously.

 

Oviposition

Adult butterflies feed on flower nectar and aphid honeydew. Females oviposit on plants with nectar immediately available for the adults even if it leads to high mortality of the larvae. This lack of discrimination indicates they do not take into account volatile chemicals released from potential host plants when searching for oviposition choices.

 

The availability of adult resources dictates a preference for specific areas of flowers. Flowers with more available nectar result in a larger number of eggs deposited on the plants. This reinforces the idea that the painted lady butterfly does not discriminate host plants and chooses mainly on the availability of adult food sources even if it increases the mortality rate of the offspring. The data also suggest that the painted lady butterfly favors quantity of offspring over quality.

 

Vision

Painted lady butterflies have a visual system that resembles that of a honey bee. Adult V. cardui eyes contain ultraviolet, blue, and green opsins. Unlike other butterflies, such as the monarch or red postman butterflies, painted ladies lack red receptors, which means that they are not sensitive to red light. Behavioral studies on the related species, Vanessa atalanta, have demonstrated that V. atalanta cannot distinguish yellow light from orange light or orange light from red light.

 

Roosting behaviour and territory

Groups of two to eight painted lady butterflies have been observed to fly in circles around each other for about one to five seconds before separating, symbolizing courtship. Groups of butterflies usually will not fly more than 4.5 m away from the starting point. To establish and defend their territories, adult males perch in the late afternoon in areas where females are most likely to appear. Once the male spots a female of the same species, he begins pursuit of her. If the foreign butterfly is a male, the original male will give chase, flying vertically for a few feet before returning to his perch.

 

V. cardui establishes territories within areas sheltered by hedgerows. Vanessa cardui tend to inhabit sunny, brightly lit, open environments and are often attracted to open areas of flowers and clovers. Adults spend time in small depressions in the ground on overcast days.

 

Host plants

Larvae feed on Asteraceae species, including Cirsium, Carduus, Centaurea, Arctium, Onopordum, Helianthus, and Artemisia.

 

The painted lady uses over 300 recorded host plants according to the HOSTS database.

 

Defence mechanisms

The main defence mechanisms of painted lady butterflies include flight and camouflage. The caterpillars hide in small silk nests on top of leaves from their main predators that include wasps, spiders, ants, and birds.

 

Human interaction

Vanessa cardui and other painted lady species are bred in schools for educational purposes and used for butterfly releases at hospices, memorial events, and weddings.

Aperture occupies virtually whole of interior face (left hand image).

1: recurved pointed umbo (rostrum) overhanging concave interior.

2: asymmetrical “ears” to either side of rostrum resemble scallop.

3: outer layer (periostracum) forms broad border beyond inner layer.

4: fractured calcareous inner-layer held in place by periostracum.

5: close-set concentric striae and a few indistinct radiating lines.

6: embayment on right side of shell.

 

Full SPECIES DESCRIPTION BELOW

PDF available at www.researchgate.net/publication/353918067_Aplysia_puncta...

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Aplysia punctata (Cuvier, 1803) Account revised August 2021

 

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=138758

Synonyms: Aplysia rosea Rathke, 1799; Aplysia hybrida J. Sowerby, 1806.

Meaning of name: Aplysia = that which cannot be washed; punctata = spotted.

Vernacular of just this species: Spotted sea hare (English); Môrwlithen glustiog (Welsh); Aplysie ponctuée (French); gemeiner Seehase (German); Pikasti morski zajček (Slovenian); Liebre de mar manchada (Spanish);

Vernacular of any Aplysia species: Sea hare (English); Lièvre de mer (French); zeehaas (Dutch); søhare (Danish); sjöhare (Swedish); Lepre marina (Italian);

GLOSSARY below.

 

Shell description

A. punctata has a rudimentary vestigial shell. Its height (longest dimension) is up to 40 mm, occasionally more; about 30% of the animal’s length. It is saucer-shape with a recurved, pointed umbo (rostrum) overhanging the concave interior, and there is an embayment on the right. It somewhat resembles a pectinid with asymmetrical “ears” either side of the rostrum.

The adult shell retains no trace of the spiral coiling of the veliger stage. It consists of two layers of conchiolin. The outer layer is the periostracum. The inner layer is transparent, imperceptibly calcified and limp on young specimens (fig. 1 flic.kr/p/DJpXbt ), and on older specimens is a translucent, thin, fragile, semi-calcareous layer, often fractured into pieces held in place by the periostracum (fig. 2 flic.kr/p/DSES2X ). The periostracum layer extends to form a broad flexible border beyond the inner layer. The exterior is amber-coloured with a sculpture of growth lines, close-set concentric striae and a few indistinct radiating lines. The aperture occupies virtually the whole of the ventral/interior face. On a living animal, the shell is concealed by the mantle (fig. 23 flic.kr/p/2oJVAzt ), except within a round foramen (fig. 3 flic.kr/p/CVh5eX ). There is no operculum.

 

Body description

The full-grown body length is about 70 mm and the usual maximum is 120 mm, exceptionally 200 mm (fig. 14 flic.kr/p/DQm3GL & fig. 15 flic.kr/p/Dqyc3s ). It has a large head and neck (fig. 4 flic.kr/p/DjbKoD ). The snout has a centrally divided oral veil which is usually loosely rolled into forward-orientated oral tentacles and curled flaps in front of the mouth (fig. 5 flic.kr/p/CVh2bn ). The appearance varies with the degree of rolling; sometimes flaps hang down from the oral tentacles (fig. 6 flic.kr/p/DJpNXK ). The snout is separated ventrally from the foot by a gutter (ffig. 5 flic.kr/p/CVh2bn ). The cephalic tentacles are also enrolled, but the edges are fused on the basal half; they resemble a hare's ears (fig. 5 flic.kr/p/CVh2bn ). Anterolaterally of each cephalic tentacle base there is a blue-black eye on a slightly raised mound of translucent unpigmented epithelium resembling a whitish iris (fig. 5 flic.kr/p/CVh2bn ).

Two large parapodia arise from the approximate mid-point of the body and extend to about 25% body length from the posterior where they unite (fig. 7 flic.kr/p/DJpNgz ). An external seminal groove runs from a common genital aperture, close to the anterior of the right parapodium, along the neck to the opening to the penial sheath near the base of the right oral tentacle (fig. 8 flic.kr/p/DJpM2a ). Raised walls along the sides of the seminal groove meet firmly at their edges, but do not fuse, to form a tube lined with cilia that propel the contents. The penis is spatulate with curled up edges and has an external seminal groove. It is engorged and extended from the everted penial sheath during copulation (fig. 9 flic.kr/p/DSEGJ8 & fig. 10 flic.kr/p/CVacmN ).

The parapodia can be held erect (fig. 11 flic.kr/p/DJpGJc ), semi-prone revealing enclosed anatomical features (fig. 3 flic.kr/p/CVh5eX & fig. 21 flic.kr/p/2nBEfgq ), or folded down to conceal features (fig. 12 flic.kr/p/DSEC4X ).

Colours and patterns on the external surfaces of body vary greatly between individuals www.nudibranch.org/Scottish %20Nudibranchs/aplysia-punctata.html (J. Anderson) , but usually there is a general progression in ground colour during growth from rose-red when small and feeding on red algae such as Delesseria, through brown or blackish-brown when on Laminaria to olive-brown when large and on Fucus (Eales, 1921). Many have fine spots of a darker shade of the ground colour arranged in elongate blotches, varying in prominence, which often form a reticulated pattern. In addition, some have white blotches. The edge of the parapodium often has a thin white rim, sometimes accompanied by black and/or reddish bands (fig. 13 flic.kr/p/DjbzG4 ), and the tips of the tentacles and edges of foot may have similar colours. The dorsal face of the parapodium, usually held concealed against the body, is unpigmented greyish white, apart from its border.

The mantle, enclosed by the parapodia, covers the shell apart from a large round foramen, and, at the posterior-right, forms an erect funnel with the anus near its base (fig. 3 flic.kr/p/CVh5eX ). The shell covers the viscera and the anal funnel fits against the embayment on its right-posterior edge (fig. 1). The anal funnel often protrudes when the parapodia are closed, but it is able to withdraw. The gill (fig. 21 flic.kr/p/2nBEfgq & fig. 22 flic.kr/p/2nBGFnR ) is a thick set, plume-like structure of loose connective tissue and muscle fibre covered by a partly ciliated epithelium (Eales, 1921, plate I). It has thickened lobes in place of the thin filaments of typical ctenidia. It is located in the narrow mantle-cavity on the right of the parapodial enclosure (fig. 3 flic.kr/p/CVh5eX ). It is affixed at its anterior end close to a yellow osphradium. The gill is usually concealed under the shell but may be erected above it if the oxygen level is sensed by the osphradium to be low. An unpigmented opaline gland is in the floor of the mantle cavity near the anterior-right of the parapodial enclosure and just to the posterior of the common genital opening (fig. 4 flic.kr/p/DjbKoD & fig. 21 flic.kr/p/2nBEfgq ). The anterior of the foot is almost rectangular and sometimes expands into a circular outline (fig. 13 flic.kr/p/DjbzG4 ). The posterior of the foot is bluntly pointed. The pale, unpigmented, narrow sole (fig. 5 flic.kr/p/CVh2bn ) is sometimes hidden by the edges curling together (fig. 11 flic.kr/p/DJpGJc ) and it may form into a rounded sucker at the anterior (fig. 13 flic.kr/p/DjbzG4 ), but rarely at the posterior (Thompson, 1976). There is no discernible subdivision of sole into regions (Eales, 1921).

 

Key identification features

Aplysia punctata

1. Parapodia unite at their posterior, c. 25% body length from posterior of body; see fig.3 in Grigg (1949) (fig. 7 flic.kr/p/DJpNgz ). It swims rarely, if at all, and clumsily if it does.

2. Foramen (fig. 3 flic.kr/p/CVh5eX ), a round hole in the mantle that exposes the shell, is larger, relative to the animal's size, than the foramen on A. depilans or A. fasciata.

3. Full-grown length about 70 mm, usual maximum 120 mm.

4. Foot occasionally expands into rounded sucker (fig. 13 flic.kr/p/DjbzG4 ) at anterior but rarely, if ever, at posterior. The sole is whitish.

5. Occurs all round Britain except parts of southern North Sea and north east Irish Sea.

 

Similar species

Aplysia depilans Gmelin, 1791

1. Parapodia unite at their posterior close to the posterior of the animal (fig.3 in Grigg, 1949) (fig. 16 flic.kr/p/DSEwU8 ). It is unlikely that it ever swims.

2. Foramen is smaller, relative to animal's size, than foramen on A. punctata

3. Length frequently 120 mm or more, up to 300 mm.

4. Foot frequently expands at posterior into rounded sucker attached to substrate. Sole brown.

5. In Britain (2015), confined to south west England; breeds in Cornwall.

 

Aplysia fasciata Poiret, 1789

1. Parapodia do not unite at their posterior. See fig. 3, as A. limacina, in Grigg (1949); frequently swims gracefully, see flic.kr/p/da9ojG (R. Fernandez); www.youtube.com/watch?v=x051Lw6LMBw#t=26 (M. Pontes).

2. Tiny foramen, pore-like on raised papilla (Grigg, 1949), is far smaller, relative to animal's size, than foramen on A. punctata; often difficult to discern.

3. Length frequently about 200 mm, with weight nearly 2kg, but up to 400 mm (largest British gastropod).

4. Foot pointed at posterior.

5. Reliably recorded from Dorset, South Devon, Cornwall and Channel Islands; rare.

 

Aplysia parvula Mörch, 1863

This species was recorded for Britain (Bebbington & Brown, 1975) on the basis of morphological features of small A. punctata specimens. Eales (1921) reported that small red specimens grew and changed colour to typical A. punctata when fed on non-red algae in captivity, so she dismissed their identification as a distinct species. Recent DNA studies (Golestani et al. 2019) found that A. parvula is confined to the tropical western Atlantic, and no DNA evidence for it was found in specimens examined from the north eastern Atlantic or Mediterranean.

 

Habits and ecology

A. punctata lives in shallow unpolluted water and occasionally on shores at LWS where its algal food grows; including red algae, Ulva (fig. 4 flic.kr/p/DjbKoD ) and Fucus.

Respiration: There is no obvious inhalent siphon; Jeffreys (1869) suggested that inflow was via the foramen, but this seems unlikely. Water is probably taken in between the body and anterior of the parapodia to the narrow mantle cavity on the right containing the gill (fig. 3 flic.kr/p/CVh5eX ). The water passes over the osphradium near the anterior attached-end of the gill. The current is created by cilia on the gill and, probably, on other surfaces. The osphradium tests the water-quality; if it is oxygen deficient, the gill may erect itself clear of the overhanging shell for better access to oxygenated water (Eales, 1921). The exhalent current leaves the animal via the anal funnel, taking faeces with it (fig. 17 flic.kr/p/DJpAiX ).

Defence : A. punctata is usually well camouflaged because its colour is often similar to alga it is feeding on. When irritated, the opaline gland (fig. 4 flic.kr/p/DjbKoD ) can release via the anal funnel (fig. 17 flic.kr/p/DJpAiX ) an acrid, white, viscous secretion, mixed with purple dye from the ink gland, to repel and confuse attackers. There are a few uncertain reports of predation on adults, but crustacea eat the spawn.

Reproduction: Breeding is recorded in February-November in Britain, but is most usual in spring. A. punctata is a simultaneous hermaphrodite, but distant spacing and positioning of the male and female orifices (fig. 9 flic.kr/p/DSEGJ8 ) prevent mutual interchange of gametes between a side-to-side pair in the manner of nudibranchs. One, acting as male, climbs astride another from behind and with the anterior of its foot firmly grips the mantle and shell (through the foramen) of the lower acting female. The penis of the acting male, engorged by blood and extruded by eversion of the internal penis sheath, is inserted into the vaginal part of the other's common genital aperture (fig. 9 flic.kr/p/DSEGJ8 ). Semen from the acting-male passes from its common genital aperture, through the external seminal groove on its neck and head, edge of the penial sheath and penis into the acting-female (fig. 10 flic.kr/p/CVacmN ). Often a chain of mating individuals forms, enabling all, except those at each end of the chain, to act as male and female simultaneously (fig. 9 flic.kr/p/DSEGJ8 ).

A. punctata often extrude spawn during coupling, and it often passes from the common genital opening along the seminal groove, escaping through a wrinkle part-way along it or continuing to emerge (confusingly) at the penial aperture. The spawn is a long string of spherical egg-capsules (fig.18 flic.kr/p/DSEwrV & fig. 20 flic.kr/p/DGfnSL ). There are about 500 capsules in each cm of spawn-string (fig. 19 flic.kr/p/DjbsiX ), and each capsule contains 3 or 4 ova. Copulation/ovipositing lasts several hours or even days, and the string is extruded intermittently in sections, each of which curls and tangles with the others (Eales, 1921). Its colour changes with time, so sections of string issued at different times by a single individual may have different shades from each other with abrupt colour changes corresponding to pauses in laying (fig. 20 flic.kr/p/DGfnSL ). The final colour is brown before veliger larvae emerge into the plankton. A mating/ovipositing chain of individuals results in a tangled mass of spawn strings. A sample mass from the River Yealm, Devon, had an estimated 135 000 ova (Thompson, 1976). Veliger larvae metamorphose after 20-22 days in the plankton at 15ºC into rose-red crawlers, about 5 mm long, feeding on red algae in shallow water (Thompson, 1976).

 

Distribution and status

A. punctata occurs from northern Norway to the Mediterranean, but is scarce or absent from the continental coast of the southern North Sea and extends into the Baltic no further than the Kattegat, GBIF map www.gbif.org/species/5191252 . It is found in unpolluted water all round Britain and Ireland, except in the north-east Irish Sea. the North Sea from Flamborough Head to Kent and much of the east coast of Scotland where it is absent or scarce. U.K. map NBN species.nbnatlas.org/species/NBNSYS0000173903

 

Acknowledgements

This account would not have been possible without the assistance of Jim Anderson, Heather Buttivant, Charlotte Cumming, Jonathan Campbell, David Fenwick, Andy Horton, David Kipling, Paula Lightfoot, Penny Martin, Simon Taylor and the photographers whose images have been linked to the account; their names are given next to the links. I gratefully thank them all.

 

References and links

 

Bebbington, A. 1992. British Aplysia species. Porcupine Newsletter Vol.5 no 6: 131 – 133. pmnhs.co.uk/wp-content/uploads/2011/11/046-PNV5N6DEC92.pd...

 

Bebbington A, & Brown, GH. 1975. Aplysia parvula Guilding in Morch, an opisthobranch new to the British fauna. Journal of Conchology 28: 329–333.

 

Eales, N.B. 1921. Memoir 24 Aplysia. Proceedings and transactions of the Liverpool biological society. 35: 183 – 280.

archive.org/stream/proceedingstr35192021live#page/182/mod...

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853), London, van Voorst. (As Aplysia hybrida); pp. 554-556. archive.org/stream/ahistorybritish05forbgoog#page/n568/mo...

 

Garstang, W. 1890. A complete list of the opisthobranchiate mollusca found at Plymouth; with further observations on their morphology, colours and natural history. J. mar. biol. Ass. U.K. 1(4): 399-457. plymsea.ac.uk/50/ .

 

Golestani, H., Crocetta, F., Padula, V., Camacho-garcía, Y., Langeneck, J., Poursanidis, D., Pola, M., Baki yokeş, M., Cervera, J.L., Jung, D., Gosliner, T.M., Araya J.F., Hooker, Y, Schrödl, M. and Valdés, Á. 2019. The little Aplysia coming of age: from one species to a complex of species complexes in Aplysia parvula (Mollusca: Gastropoda: Heterobranchia) Zoological Journal of the Linnean Society. 20, 1–52

 

Grigg, U.M. 1949. The occurence of British Aplysia. J. mar. biol. Ass. U.K. 28(3): 795-805. plymsea.ac.uk/id/eprint/1391/ [has A. fasciata as A. limacina]

 

Høisæter, T. 2009. Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna norvegica 28: 5-106. www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/563

 

Jeffreys, J.G. 1862-69. British conchology. vol. 5 (1869). London, van Voorst. pp.1-8 archive.org/stream/britishconcholog05jeff#page/n9/mode/2up .

 

McKay, D. & Smith, S.M. 1979. Marine mollusca of East Scotland. Royal Scottish Museum, Edinburgh.

 

Thompson, T.E. 1976. Biology of opisthobranch molluscs vol.1. London, Ray Society.

  

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=138758

 

Glossary

aperture = mouth of gastropod shell; outlet for head and foot.

anterolateral = situated in front and to the side of.

cephalic = (adj.) of or on the head.

cilia = (sing. cilium) microscopic linear extensions of membrane that move in rhythmic waves to create locomotion, or that move particles and liquids e.g. inhalent water currents. (Scanning electron microscope image at flic.kr/p/qQB5zj )

 

ciliated = (adj.) coated with cilia.

conchiolin = horny flexible protein that forms the periostracum and a matrix for the deposition of calcium carbonate to create other shell-layers.

 

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments or lamellae on one or two sides.

 

ELWS = extreme low water spring tide (usually near March and September equinoxes).

 

epithelium = tissue forming outer layer of body surface and lining the alimentary canal and other hollow structures

 

everted = turned inside out and, like a sock.

foramen = natural, non-accidental, opening.

lobate = having or resembling lobes.

LWS = low water spring tide.

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs. Confined to the shell-interior of most British shelled-gastropods, but also covers exterior on Aplysia.

 

opaline = acrid, white, viscous secretion used with purple ink by Aplysia to repel attackers.

operculum = plate of horny conchiolin, rarely calcareous, used to close shell aperture. Absent from Aplysia.

 

osphradium = organ for testing water quality, usually near the gill.

parapodia = (sing, parapodium) flap-like, lateral outgrowths of foot, usually held up against the sides of some sea slugs.

 

pectinid = member of the family Pectinidae (scallops).

periostracum = thin horny layer of chitinous material often coating shells.

plankton = animals and plants that drift in pelagic zone (main body of water).

plicate = corrugated so ridges and grooves alternate with each other on either side of axis.

rostrum = beak-like process on shell.

semen = fluid containing sperm.

seminal = relating to or containing semen.

striae = (sing. stria) usually parallel, slight, fine or narrow furrows, ridges, stripes, or streaks.

umbo = (pl. umbones) earliest part of the shell of a bivalve and some bivalve-like gastropod shells, such as in Aplysia punctata. It terminates in a beak which is best seen on an interior view.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

  

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Glossary

  

Canola is a trade name for the refined oil but is sometimes used to refer to the whole plant.

 

Oilseed rape is a very useful crop as the seed is typically 42% oil and the meal left after removing the oil is about 42% crude protein. Furthermore the oil is particularly high quality and high in monounsaturates and should logically be a premium product (as it is as "Canola", the trade mark of rape oil produced in parts of North America).

 

The meal is a useful animal feed.

 

There are two quality types

Edible oils, used as a food grade oil.

It is most often encountered as an odourless frying oil low in unsaturated fats but it is also an ingredient in many food products, especially where a "healthy" oil is required.

Industrial (although some edible types are also used industrially), which are NOT edible but have been bred to contain high levels of compounds critical for some industrial processes.

Even the raw oil, with some adjustment, will run diesel engines (it can be run on its own but apparently doesn't do the engine much good.)

One of the contributors to UBA has, for the last couple of years used it in the oil tank of his chainsaw. This is a total loss system, on a busy day about 2litres gets thrown off the chain between two operatives. He buys it direct from the local supermarket. (This is not recommended for a saw not in regular use as if left it gums up the system and after a while the saw acquires a green tinge.

The plant

Rape seed is a tiny round black seed and is sown at 3 to 8 kg/Ha (ie at under 1gm/sq m) which germinates rapidly to produce a typical brassica (cabbage family) plant. After a period of establishment it runs to flower producing the characteristic brassy yellow flowers and a faint odour of honey.

 

Honey

It is responible for much of the honey produced in lowland UK, although the honey is so strong it tends to crystallise and so is often blended. The pollen is designed for pollination by bees and is heavy and sticky (as anyone who walks through a field in flower will discover).

 

Harvesting

The seed pods are about 5mm in diameter, pointed at both ends, and 30 to 80mm long. Harvesting may be preceeded by dessication (spraying to kill the plant evenly) or swathing/windrowing (cutting the plant and leaving it on the stubble to dry) or direct cutting with a combine harvester. Attachments to the front of the combine are common for both picking up the windrow or direct cutting (which often comprises a long extension between the knife and the combine intake). The pods are easily shattered and the seeds lost and the small ballbearing-like seeds will run like water through any tiny holes.

 

Several species of bird, including the Linnet (a farmland bird in decline), are able to take advantage of rape crops for food. Others, including Sedge Warbler and Reed Bunting, regularly use it for nesting. Their breeding attempts often last beyond the desication or cutting point and rsearch has shown that the bird's nests almost always survive the spraying process but most are destroyed by cutting.

  

Some local language..

 

Glossary of Cattle Stations Terms

in STATIONS, STORIES AND ARTICLES

A list of terms commonly used on Australian cattle stations. Sayings vary from place to place and originate from all over Australia.

   

1080 – A poison for wild dog control.

 

Big Smoke – city.

 

Billy – a tin used over a campfire to boil water for tea. See also “Boil the billy”.

 

Blocking cattle up – Generally refers to mustering on horseback when the cattle are first approached. They are usually held in one spot for a time until they have quietened down enough to move forward.

 

Blowie – a blow fly – a large fly that lays maggots making meat rotten.

 

Bodgy (or Dodgy) – poor quality. “It’s a bit bodgy” – it might fall to bits.

 

Boil the billy – “Let’s have a break for a cup of tea or coffee.” Often used even when the water is boiled with an electric jug. See “Billy” above.

 

Bore Runner – A person who drives around the station usually 2 or 3 times a week checking the water for the cattle. The water can be in dams or natural waterholes but it is often underground water which needs to be pumped by a windmill, solar or diesel motor. Some underground water flows to the surface without pumping.

 

Bronco (Bronco Branding Broncoing) – The traditional Australian method of branding calves. The Calves are caught by throwing a lassoo from the back of a strong horse. The calf is then pulled up to a timber panel for branding. This method of branding calves is not often used anymore but it’s become a popular sport.

 

Bronco Panel – A timber fence like structure for restraining calves while they are being branded using the broncoing method.

 

Bronco Yards – Yards to contain cattle while Bronco branding.

 

Bullock – A castrated male cow

 

Bush – has different meanings depending on where you are. If in town, “going to the bush” might mean heading out of town, or if in the city, going to a small country town. To people in city regions “the bush” could refer to the outback. When in the country, “going up the bush” could mean going to an area where there are lots of trees and wildlife, and “going bush” could mean going out where there are no other people, maybe to do fencing or go fishing. Going bush could mean someone wanting to get away from other people.

 

Bush telegraph – the exchange of information by word of mouth. “I heard it on the bush telegraph”, just like “I heard it on the grapevine”.

 

Camp – “I’m going to have a camp,” meaning a rest. Also another name for stock camp or fencer’s camp, etc.

 

Chopper – Helicopter; usually used for mustering cattle.

 

Clean skin – an unbranded and unearmarked heifer, cow or bull.

 

Cockie – Farmer. Also slang for cockatoo and cockroach. See also “Cockie Gate”.

 

Crossbreed fender saddle – The style of saddle which is used almost exclusively on cattle stations. The crossbreed refers to the combination of the Australian knee pads, seat and cantle and the American style panels and lining.

 

Cruisie – taking it easy, “A cruisie job” – an easy job or affirmative “Cruisie”- that will be fine, cool.

 

Cuppa – a cup of tea or coffee. “Let's have a cuppa” – to have a break for a cup of tea. See also “Smoko”.

 

Dodgy (or Bodgy) – poor quality. “It’s a bit dodgy” – it might fall to bits.

 

Donkey – Usually a drum of water with a fire underneath stoked up when hot water is needed for showers.

 

Draft / Drafting – Usually refers to separating cattle into different categories for branding, trucking or treating. Can be done on horseback or in a yard.

 

Drafting – Can also refer to the sport of campdrafting.

 

Fats – fat cattle ready to be sold for slaughter, can be either bullocks or cows.

 

Float – a word often used when outback people are ready to go somewhere, “Let’s float”, or have gone, “He’s floated”. They could be going out to the stock camp, going to a rodeo or changing jobs.

 

Fresh horse – a horse that hasn’t been used for a while.

 

Gates – some of the different names for gates common in the country, usually made from wire and wooden posts or stakes and having a wide range of styles of latches.

 

Bogan Gate

Bowyan Gate

Cockie Gate (see also “Cockie”)

Wire Gate

5 minute gate (5 minutes to make and 5 minutes to open)

COD Gate (Carry or Drag)

 

Gibber Plains – Open plain country with not much grass cover and small rocks lying on top of the ground.

 

Greenhide – Untreated cowhide which was used traditionally for making ropes, halters, bridles, pack bags as well as many other station uses.

 

Green horse – a horse, broken in but with not much training or experience.

 

Green Ringer – inexperienced station hand

 

Hang up – ride a bucking horse without getting thrown off, “he can hang up”.

 

Have a blow – have a rest.

 

Hobble – To join the front legs of a horse with two straps and a swivel chain (usually at night) to stop them going too far from camp.

 

Holding the cut / cutting – When cattle are drafted on horseback it is often refered to as cutting and the cattle that have been separated from the mob are called the cut.

 

Horse plant (or just ‘plant’) – The group of workhorses kept ready for work at any time; either “hobbled” (see previous entry) out at night or kept in a small paddock. The group of horses in use by the stock camp at any one time. See also “horse tailer” below.

 

Horse tailer – the person who looks after the plant horses (see previous entry) while mustering or droving. See also “Tailing”.

 

Humbug – an annoying person.

 

Humbugging – teasing, pestering.

 

Hung up – to come off a horse and have your foot caught in the stirrup iron (oxbow) and get dragged along. (Not to be confused with Hang up)

 

Inside – closely settled region – an old time saying to distinguish areas which are closely settled from the sparsely settled frontier country, or outside (a word which changed over time to outback).

 

Jackeroos and Jillaroos – Usually young station workers who in times past often lived and ate separately from station hands, but all worked together. Even though we still see ads for jackeroos and jilleroos, young people much prefer to be called “ringers”.

 

Killer – one of the stock to be slaughtered for eating on the property.

 

Knock it off – stop that nonsense or to steal something.

 

Knock off – finish work for the day – “I’m going to knock off now”.

 

Knock off time – “When is knock-off time?” – when will we finish work for today?

 

Micky bull – a young bull, usually up to about 18 months of age, which should have been branded and castrated but has been missed in previous musters.

 

Mob – group of cattle, horses or sheep running or mustered together. Can also be a description of a family or station grouping, eg “the Humbert River mob”. Can be used to describe a large number of just about anything, eg “the biggest mob of beer”.

 

Mothering up – Calves are often separated from their mothers during mustering and processing through the yards. Before the cattle are let go they are held together to allow the cow and calf to find each other.

 

Muster – round up sheep or cattle. Noun – “this year’s muster”, or verb – “we’ll muster them in”.

 

No drama or No worries – forget about it (in forgiveness) or Yes, I’ll do it (it will be no problem). See also “Too easy”.

 

Offsider – assistant. Usually younger or less experienced.

 

Outback – originated in a time when closely settled regions were referred to as inside and the sparsely settled frontier country was referred to as outside. The word outside changed over time to outback. “The Outback” has now become a tourism catchphrase to describe the sparsely populated central, western and northern regions of Australia. It is not a specific place, more a description, a bit like calling Australia “Down Under”.

 

Paddock – fenced area.

 

Piss holes – A small water hole.

 

Plant – see “Horse plant”.

 

Reckon – “Do ya reckon?” = Do you think so? or “I reckon!” = I agree wholeheartedly, or “I reckon it will rain tonight” = I think it’s going to rain tonight.

 

Ringer – a male or female stock worker on an Australian cattle station, so named from rounding up “mobs” of cattle. See our Working as a Ringer article.

 

Ringing – A term for someone who is a ringer eg I’ve spent the last 10 years ringing in the Northern Territory.

 

Rollie – a self rolled cigarette.

 

Roo – Slang for “jackeroo” or “jilleroo”. A term often used for a person who is inexperienced or meaning that the person is not very skilled. Also short for kangaroo.

 

Round / A round – “Mustering” all the cattle on the station; mostly done twice in each season in a first and second round.

 

Saddle Bronc – The sport at a rodeo in which a rider attempts to ride a horse that in inclined to buck.

 

Scuffling crops – Small crops were traditionally cultivated using a draft horse pulling a tyne like implement.

 

Smoko – a break for a smoke or a cup of tea or coffee. See also “Cuppa”.

 

Stock Camp – See our Cattle Stations page for an explanation of the term “Stock Camp”.

 

Surcingle – A leather strap used to secure a riding or pack saddle onto a horse. The surcingle goes around the saddle and horse.

 

Tailing – to contain a “mob” of cattle or horses while they graze. For example:

 

tailing cows and calves – to mother up;

tailing the mob – they may have been in the yards and need a feed.

tailing the “plant horses” while mustering or droving.

tailing weaners (see “weaners”) – to quieten, feed and educate them while they are adjusting to being taken from their mothers.

Too easy – similar to “No drama” or “No worries” = I’ll do it, it will cause no problems.

 

Town smokes (sometimes called “townies”) – tailor made cigarettes. Called town smokes because station workers often only smoke them when in town as a bit of a luxury. When out on the station they would mostly smoke “rollies”.

 

Tucker – food. See also “tucker box”.

 

Tuckerbox – food box. See also “tucker”.

 

Turkey nest – A circular earth tank built above ground that has water pumped into it from a bore or water hole or dam. The water in the turkey's nest gravity feeds to troughs for cattle or sheep to drink.

 

Vesty – An English company owned by Lord Vesty that owned many cattle stations in the north of Australia during the 20th century.

 

Weaners – young steers or heifers, usually six to eight months old, recently weaned from their mothers.

 

Yard – a structure used to hold and process cattle. See also “yarded” below.

 

Yarded – “the cattle have been yarded” – put in the yard (see previous entry).

 

Thanks to this site... kentsaddlery.com.au/2011/02/glossary-of-cattle-stations-t...

by Bill and Nancy Malcolm

 

beautiful book

When in water, the body is more swollen, and both shell and body are more translucent, lighter and brighter in colour, and less reflective, than when in air.

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

GLOSSARY BELOW

Preface

[EDIT July 2021: specimens illustrated in this account which were supplied to Amgueddfa Cymru (the Natural History Museum, Wales) were sequenced by Ben Rowson who found no difference in the DNA of M. myosotis and M. denticulata and concluded that they were a single species; Myosotella myosotis. This has now been accepted by WoRMS; see www.marinespecies.org/aphia.php?p=taxdetails&id=139672 ]

The World Register of Marine Species (WoRMS) accepts Myosotella myosotis and M. denticulata as valid species, but those identified as such in Britain may be distinct ecotypes of a single species. A possibility, raised by Martins (2013), is that the true M. myosotis (Draparnaud, 1801) occurs in the Mediterranean and that both British shell forms are ecotypes of M. denticulata (Montagu, 1803). This account treats them separately as, whichever status is determined by planned DNA sequencing, they have distinct apertural sculptures associated with different habitats.

Because of its special habitat intermediate between terrestrial and marine, this species, and its Myosotella and Leucophytia relatives in the family Ellobiidae, are omitted from some identification guides, while variously appearing in others devoted solely to either terrestrial, marine or even freshwater mollusca.

  

Myosotella myosotis (Draparnaud, 1801)

Synonyms: Auricula myosotis Draparnoud, 1801; Ovatella myosotis (Draparnaud, 1801); Alexia myosotis (Draparnaud, 1801); Phytia myosotis (Draparnaud, 1801); Conovulus denticulatus var. myosotis in Forbes & Hanley (1853); Melampus myosotis in Jeffreys (1869);

Vernacular Probably also applied to M. denticulata: Mouse-eared Alexia, Mouse ear(ed) snail (English); Clust llygoden (Welsh); Evesnegl (Danish); Muizenoortje (Dutch); Ovatelle naine des vases (French); Stranddvärgsnäcka (Swedish); Mäuseöhrchen (German);

Applied to just this species/ecotype: Estuarine mouse-ear (English); Gewoon muizenoortje (Dutch);

 

Description

When in water, the body is more swollen, and both shell and body are more translucent, lighter and brighter in colour, and less reflective, than when in air 1Mm flic.kr/p/2drL1Pw . The following shell description is of specimens in air.

Shell

Juvenile shell usually less than 6.5mm high. Adult shell usually up to 8mm high and 3.5mm broad, exceptionally 10mm high and 5mm broad; ridge often within palatal (outer) lip 2Mm flic.kr/p/2exLLRc . Fusiform shell, width 45% to 50% of height 3Mm flic.kr/p/23Wmsve . Small spire with sharp apex; body whorl c. 73% of height of 7.5mm adult; 77% of 5.8mm juvenile; 80% of 4.4mm juvenile. Apex slightly twisted due to change from sinistral protoconch to dextral teleoconch. Shell-wall thin, opaque or slightly translucent, with a silky sheen when clean 2Mm flic.kr/p/2exLLRc . Up to 8 moderately convex whorls separated by distinct shallow sutures. On juveniles, the periostracum is drawn into a row of bristles below the sutures 4Mm flic.kr/p/23Wmsjc , but they are worn off over time; a few bristles may survive on adult shells. Earliest juveniles with three or fewer whorls lack periostracum and bristles; their shells are white-translucent with punctate spiral lines which may persist for a time as the shell grows 5Mm flic.kr/p/23Wms8v ; other later whorls may have them concealed under the periostracum. Very fine, closely spaced, costal lines sometimes visible on adults, especially on spire whorls 6Mm flic.kr/p/23Wms6g . Growth lines sometimes emphasised by change of shell colour 7Mm flic.kr/p/2drL14d . Usually no umbilicus except for an umbilicus-like slit in the apex caused by the change from the sinistral larval shell (protoconch) to a dextral shell 5Mm flic.kr/p/23Wms8v . Within the shell, when it reaches 2½ whorls, the columella and septa between the spire whorls are resorbed by the mantle, leaving an open space except for the columella and septum of the body whorl 8Mm flic.kr/p/23WmrU4 & 9Mm flic.kr/p/2drKZRQ . Aperture about 50% of adult shell height, 65% of 4.6mm juvenile; shaped like a narrow ear with a rounded base and a sharp adapical angle 3Mm flic.kr/p/23Wmsve & 10Mm flic.kr/p/QMuYsB . Palatal (outer) lip of juveniles (under c.6mm shell-height) is thin without protrusions (folds/teeth/denticles); lip sometimes weakly reflected 4Mm flic.kr/p/23Wmsjc on adults (over c.6mm high) often with a pale calcareous ridge within the aperture near the palatal rim. The ridge sometimes contains a single raised white denticle that is often only weakly developed. The columellar/parietal lip (inner lip of aperture) has two or three protrusions . The parietal lip consists of a wide glazed area on the body whorl. For a clear view of the features within the aperture, including, sometimes, a far-back palatal ridge formed at a previous pause in growth, the animal may need a prod with a small brush to make it withdraw, and the shell requires tilting at different angles 11Mm flic.kr/p/2drKZKC . There is no operculum 12Mm flic.kr/p/QMuYge . Exterior colour varies from pale yellowish brown to dark reddish brown or, sometimes, purplish brown 2Mm flic.kr/p/2exLLRc . Sometimes the shade of brown changes at growth lines 7Mm flic.kr/p/2drL14d , and, frequently, the spire is darker than the body whorl 3Mm flic.kr/p/23Wmsve . The protoconch and juvenile shell up to 1.4mm height are white 13Mm flic.kr/p/2drKZr1 , and are retained as a white apex on the adult 2Mm flic.kr/p/2exLLRc . On adults, the pale ridge within the aperture may show as a pale band on the exterior of the slightly translucent shell 11Mm flic.kr/p/2drKZKC . Shells on saltings are often coated with mud 14Mm flic.kr/p/QMuY3i . On dead stranded shells the periostracum often peels off and the colour bleaches to whitish 15Mm flic.kr/p/2drKZdL .

Body

Upper parts of head and body that are exposed by normal extension are various shades of grey including whitish-grey, steel-grey and brownish-grey to nearly black 6Mm flic.kr/p/23Wms6g & 16Mm flic.kr/p/QMuXMt , but rarely, if ever, pure white; colour on an individual varies with degree of extension and whether in air or water, and its intensity may increase with age. The colour is arranged in transverse bands across the dorsum 7Mm flic.kr/p/2drL14d , and as a mosaic of tessellating blotches on the sides of the head 16Mm flic.kr/p/QMuXMt . Sides of foot are greyish white or a paler grey than the dorsum 17Mm flic.kr/p/2drKYVb . Body parts normally concealed by the shell have less pigment and show the white of the internal oesophagus with flanking salivary glands, reproductive organs and retractor muscles when the body is extended to its maximum 7Mm flic.kr/p/2drL14d & 18Mm flic.kr/p/QMuXBi . When immersed, the body absorbs water and swells, the body colour becomes paler, and translucency of the shell and body increases 19Mm flic.kr/p/2drKYKG . The mantle sometimes projects a short way beyond the aperture rim of the palatal lip, but is not reflected onto it 20Mm flic.kr/p/2da1VEX . The parietal lip on the body whorl is a glaze formed by the mantle extending onto it. Within the shell, the mantle is very thin, semi-transparent and colourless apart from a faint, fine, pale-grey speckling. Where it roofs the mantle cavity 21Mm flic.kr/p/2da1VyK , it contains many haemolymph vessels which are occasionally visible through translucent juvenile shells 22Mm flic.kr/p/2drKYpG or on dissected mantle. The mantle cavity, which functions as a lung for respiration, is sealed off from the exterior by a thick, white or brownish-white, membranous mantle-collar which fits closely round the body as it extends or retracts 23Mm flic.kr/p/QMuSQV & 24Mm flic.kr/p/2drKYky . The collar has a pneumostome which, when in air, can be opened and closed 25Mm flic.kr/p/2exLJ2K for respiration and humidity control but, when immersed, does not effectively retain air or exclude water 26Mm flic.kr/p/2drKY7h . The rectum and part of the intestine, visible through translucent shells in water 22Mm flic.kr/p/2drKYpG , runs along the rear edge of the roof of the mantle cavity 21Mm flic.kr/p/2da1VyK to the anus which opens to the exterior in a folded part of the mantle-collar 27Mm flic.kr/p/2da1UTX in the adapical angle of the aperture close to the pneumostome. The head has two cephalic tentacles; nearly linear with a bluntly pointed tip (subulate) when dry, and conical and paler when swollen with water 16Mm flic.kr/p/QMuXMt . When not extended, they are contracted into crumpled stumps 28Mm flic.kr/p/2drKY1q , not retracted by inversion into the body. Both when extended or contracted, the tentacles widely diverge from their bases near the midline of the head 28Mm flic.kr/p/2drKY1q & 29Mm flic.kr/p/2da1UNr . The distal half of the tentacles, sometimes slightly bulbous, is brownish and contains sensory chemoreceptor cells (Wondrak, 1984) 29Mm flic.kr/p/2da1UNr . There is an internal black eye within the posteromesial base of each tentacle 29Mm flic.kr/p/2da1UNr & 30Mm flic.kr/p/2drKXUJ . Distinctness of eyes varies with intensity of body pigment and amount of flesh they are viewed through. The head in front of the tentacles forms a broad, slightly bilobed “muzzle” (Forbes & Hanley,1853) which can be variably configured, but not cylindrically to form a snout like that of many marine gastropods. When not feeding, it forms a shallow curve over the mouth in anterior view, and a steep anterior in profile view 28Mm flic.kr/p/2drKY1q . Near the anterior edge of the muzzle are two button-like, faintly-brownish grey pads (“fungiform bodies” of Wondrak, 1984) 28Mm flic.kr/p/2drKY1q which contain sensory cells. Ventrally, the mouth is protected by white outer-lip lobes. When feeding, the ventrally translucent-white muzzle is spread out flat on the substrate and the outer lips moved aside 31Mm flic.kr/p/SpE2GS to expose the mouth edged anteriorly by the rim of the red-brown jaw, and to allow the extension of the anterior of the radula covered in thousands of white teeth. When translucent, the muzzle may reveal dorsally the oral tube leading from the mouth to the buccal mass, and the oesophagus passing from it towards the stomach 18Mm flic.kr/p/QMuXBi . The stomach is a large sac, partly surrounded by digestive gland. On specimens removed from the shell, the transparent lateral surface showing the stomach contents is prominently visible on the left of the visceral mass 32Mm flic.kr/p/2exLHtF , and the gizzard-like girdle of strong, white, folded muscle fibre surrounding it may be seen if the visceral mass is opened 33Mm flic.kr/p/2da1Uvc & 34Mm flic.kr/p/2exLHiF . Unlike the spiral viscera of most gastropods, the viscera of M. myosotis forms a non-spiracular, approximate cone 35Mm flic.kr/p/2da1Uo8 to fill the spire after the columella and septa are resorbed 8Mm flic.kr/p/23WmrU4 & 9Mm flic.kr/p/2drKZRQ , with a small colourless tip formed in the shell's early pre-resorption stage. On weakly pigmented, translucent specimens (most often juveniles) the dumbbell-shaped, dorsal part of the nerve ring with two cerebral ganglia may be visible 24Mm flic.kr/p/2drKYky . The ring encircles the oesophagus. It and its ganglia that innervate organs on the head are the nearest approximation in gastropods to a centralised brain, but other ganglia distributed on nerve cords around the body innervate other organs 36Mm flic.kr/p/2exLH8v . The anterior edge of the translucent white sole is broad and almost straight, sometimes with a slightly indented middle, and tapers to a rounded posterior 25Mm flic.kr/p/2exLJ2K . M. myosotis is a protandrous hermaphrodite with a penis shaped as a stout cone with the vas deferens running up the centre. The penis is normally inverted within the body, and everted for mating by hydrostatic pressure of haemolymph from an opening on the right side of the head to the rear of the tentacle 37Mm flic.kr/p/2da1Uac .

 

Key identification features

Features 1 to 4, below, accord with Forbes & Hanley (1853) and Gittenberger (2004). The former aggregated M. myosotis sensu stricto with M. denticulata but “scrupulously kept apart their description.” Many currently used identification guides aggregate them and their features under M. myosotis sensu lato. Consequently, distribution maps on GBIF and NBN include many M. denticulata occurrences under “M. myosotis”, and the M. denticulata maps have under-representation of its occurrence. If making a differentiated record, 'sensu stricto' should be added to the record to enable it to be distinguished from lumped records.

To observe aperture sculpture the animal must be well withdrawn, and the shell tilted at different angles. Sometimes the outer (palatal) lip sculpture of an earlier growth stage is visible deep into the aperture and should be used if the sculpture on new growth has not yet developed. It is advisable to examine several specimens of different sizes from a site; sometimes both are present.

 

Myosotella myosotis

1. Live shell brown 2Mm flic.kr/p/2exLLRc (beachworn shells may be dull whitish 15Mm flic.kr/p/2drKZdL ). Usual adult height 6.5mm to 8mm, exceptionally 10mm .

2. Inner (columellar/parietal) lip has only 2 or 3 apertural protrusions 3Mm flic.kr/p/23Wmsve .

3. Outer (palatal) lip has a single apertural denticle or none 3Mm flic.kr/p/23Wmsve . Some have a pale apertural ridge running close to the lip.

4. Flesh colour of normally extended dorsal body is grey 1Mm flic.kr/p/2drL1Pw . Shade and intensity varies with age, extension and whether in air or water, but not pure white when adult.

5. Habitat: among vegetation, often under driftwood, on low salinity estuarine saltings 38Mm flic.kr/p/2exLH2t and Saltmarsh-grass sward by tidal rivers 39Mm flic.kr/p/2da1TMi a little above and below EHWS. Locally abundant. (May occur with M. denticulata under stones on/near saltings 40Mm flic.kr/p/2exLGc2 .)

  

Similar species/ecotype

Myosotella denticulata

(full account flic.kr/s/aHskQdY4cp)

1. Live shell brown (beachworn shells may be dull whitish). Usual adult height 3.5 mm to 7.5 mm, exceptionally 10 mm 45Mm flic.kr/p/QMuTi8 .

2. Inner (columellar/parietal) lip has 3 to 5 apertural protrusions 45Mm flic.kr/p/QMuTi8 .

3.Outer (palatal) lip has 2 to 7 (or more) apertural protrusions 45Mm flic.kr/p/QMuTi8 , sometimes set into a pale ridge which occasionally submerges them. [If no protrusions, check further back in aperture for protrusions on earlier lip position; may be visible from exterior through translucent shell , with or without connecting streaks.]

4. In its typical non-salting habitat, the flesh colour of normally extended dorsal body is white or very pale whitish grey, with darker grey tentacles 46Mm flic.kr/p/2da1NUc . But when it occurs in muddier conditions, it may be as dark as M. myosotis 47Mm flic.kr/p/QMuSYv .

5. Habitat: typically under slightly embedded stones at Extreme High Water Spring level and above (supralittoral) on sheltered coast without salting vegetation at fully marine salinity. Occasionally under stones on landward edge of Saltmarsh-grass sward by tidal rivers with low salinity 40Mm flic.kr/p/2exLGc2 .

 

Leucophytia bidentata (Montagu, 1808).

(Full account flic.kr/s/aHsmwhDvaL )

Features 1 to 4 conform with Montagu's original description and image.

1. Live shell slightly-translucent ivory-white; yellow viscera may show through spire 48Mm flic.kr/p/2da1NEe . Usual adult height to 5 mm, occasionally to 7 mm. Sutures shallower and whorls less rounded than on M. myosotis 49Mm flic.kr/p/2da21sH .

2. Inner (columellar/parietal) lip has 2 protrusions within the aperture; not more 49Mm flic.kr/p/2da21sH .

3. Outer (palatal) lip has no protrusions or rib (sometimes in a photo, a strong growth line might be mistaken for a rib 49Mm flic.kr/p/2da21sH ).

4. Flesh colour of normally extended dorsal body is amost pure white 48Mm flic.kr/p/2da1NEe , but when contracted into body-whorl colour saturation gives it a cream appearance.

5. Lives in deep, silty, rock crevices between High Water Neap level and Low Water Spring level. Also under stones embedded into soil-like substrate at Extreme High Water Spring level and a little above on sheltered coast where it is often with M. denticulata.

 

Habits and ecology

M. myosotis lives in the upper littoral fringe at, and a little below, the level of EHWS tides at the base of halophyte vascular plants on estuarine saltings 41Mm flic.kr/p/QMuUAP and in Saltmarsh-grass sward (Puccinellia maritima) along tidal rivers 39Mm flic.kr/p/2da1TMi & 42Mm flic.kr/p/2exLEJH . This zone can be extensive on large, flat, estuarine saltings 38Mm flic.kr/p/2exLH2t or as little as a metre wide on steep river banks 39Mm flic.kr/p/2da1TMi . At its upper limits, at or a little above EHWS, M. myosotis intermingles with some terrestrial invertebrates. It does not live in permanently submerged in pools, but can survive and be active for the short period of immersion (c. 1 hour) that occurs on 2 to 6 days per month. It lives semi-subterraneanly under driftwood 43Mm flic.kr/p/QMuTCB or large debris, or in the groundcover matt of vegetation and debris which, for moving through, its spindle shaped shell is well adapted. When moving, the foot is cushioned on a layer of watery mucus and the shell has a thicker layer between it and the substrate 17Mm flic.kr/p/2drKYVb . Under large pieces of wood or debris it favours the central darkest part while Assiminea grayana, if present, is found near the periphery. After immersion or during rain, it may be active in the open when its tentacles wave in the air to detect odours and, in the absence of anterior tentacles found on most pulmonates, its oral tube tests wet substances on the substrate (Wondrak, 1984). The two button-like, faintly-brownish grey pads (“fungiform bodies” of Wondrak, 1984) 28Mm flic.kr/p/2drKY1q near the anterior edge of the muzzle are also sensory.

It is a euryhaline species capable of surviving immersion in water from 0 p.p.t to full marine salinity or more, but individuals require time to adapt to changes in salinity and may become inactive/moribund when abruptly immersed in water they are unaccustomed to.

Respiration is of atmospheric air in the mantle cavity which is sealed by a white collar of thickened mantle 23Mm flic.kr/p/QMuSQV that firmly embraces the body but allows it to extend-from/retract-into the shell 24Mm flic.kr/p/2drKYky . A pneumostome (respiratory pore) in the collar 25Mm flic.kr/p/2exLJ2K can be opened for inhalation/exhalation of air or closed to seal the cavity against dehydration.The roof of the mantle cavity contains a network of haemolymph vessels 21Mm flic.kr/p/2da1VyK and is very thin, enabling oxygen from inhaled air to diffuse into the vessels and for carbon dioxide to leave with the exhaled air. When immersed, air escapes from the mantle cavity 26Mm flic.kr/p/2drKY7h and water enters 24Mm flic.kr/p/2drKYky . M. myosotis can survive immersion for at least three days with no access to atmospheric air. Long submersion with water in the mantle cavity is well tolerated if the water's oxygen content is high 22Mm flic.kr/p/2drKYpG (Seelmann, 1968, in Gittenberger, 2004).

When feeding, the muzzle is spread out on the substrate and the radula is extended 31Mm flic.kr/p/SpE2GS to gather, with the red jaw as a backstop, decaying vegetation, diatoms (Wiese & Richling, 2008) and sediment rich in organic material which are bound into food boli with mucus from the supra pedal gland brought to the mouth along a median groove. The boli travel along the oesophagus 36Mm flic.kr/p/2exLH8v to the stomach 32Mm flic.kr/p/2exLHtF & 34Mm flic.kr/p/2exLHiF where strong muscular contractions of the internally-folded gizzard triturate them and squeeze out semi-fluid nutrient which passes into the diverticula of the digestive gland for digestion. The residual mass is squeezed as faecal boli into the intestine by muscular contractions 34Mm flic.kr/p/2exLHiF and passes to and through the rectum 21Mm flic.kr/p/2da1VyK . Unlike marine prosobranch gastropods, which defecate into a mantle cavity that is cleared by water currents, M. myosotis has a rectum that opens to the exterior through an anus in the mantle collar, near to, but separate from, the pneumostome 27Mm flic.kr/p/2da1UTX so that faeces are expelled without fouling the respiratory mantle-cavity. The soft faeces, wet and loosely bound with mucus when fresh, dry to thin granular threads consisting mostly of fine mineral particles 44Mm flic.kr/p/2da1Pyi .

Reproduction: in NW Germany, copulation is in all months with peaks in April/May and August/September (Schultes,2014). Ova are laid when the temperature is above 15°C from late spring to late summer (Gittenberger, 2004). It is a protandrous hermaphrodite which changes its sexual function in the wild when 1½ to 2 years old, so younger, 1 to 1½ years, fully mature males mate with older, over 1½ years, females (Schultes, 2014) using the stout, conical penis everted from the side near the posterior of the right tentacle. Sometimes, a chain of three individuals mate, with the middle one acting as both male and female. Under optimal laboratory conditions, newly hatched animals can reach a shell length of 5 mm and start laying eggs in 8 weeks (Wiese & Richling, 2008). Each month of the breeding season, a female deposits 15 to 80 egg capsules (Schultes, 2014) in a small, yellow or white, frog-spawn-like mass (Morton, 1954 and Gittenberger, 2004). Each ovoid capsule contains a single ovum. The cases are attached to each other in a loosely convoluted chain by a filament (chalaziform process) at each end. The closely packed cases with intervening clear fluid are contained in a tough binding membrane which is attached to stones, plant stems, wood etc in moist situations (Morton, 1954) or in soil cavities in clusters from several females (Schultes, 2014).There is a larval veliger stage, with sinistral shell, which is passed entirely within the ovum (Morton, 1954). At 10 °C to 20 °C and 18 p.p.t. salinity, crawling juveniles emerge after about two and a half weeks. At less favourable salinities, less than 18 p.p.t or more than 54p.p.t., development takes several weeks longer (Gittenberger, 2004), though the eggs are moist but not immersed for most of the time. Juveniles in northern Germany hatch after 3-7 weeks, and 12-15 days in France (Schultes, 2014). Individuals can live to 3 or 4 years of age (Wiese & Richling, 2008).

 

Distribution and status

Europe from Orkney, Scotland and southern Denmark to Mediterranean and Azores; majority of records are from Britain and Ireland. Locally abundant in suitable habitat in Britain. Occurs in German Baltic saltmarshes, but habitat threatened in Germany (Wiese & Richling, 2008). Assumed to have been introduced to temperate coasts of Australia and North America (Atlantic and Pacific) GBIF map www.gbif.org/species/2297460 , but comparison of soft part morphology suggests that many different species have been aggregated because of similar shell morphology (Martins, 2013).

Widespread around Britain but non-estuarine records are likely to be the species/ecotype M. denticulata NBN map

species.nbnatlas.org/species/NHMSYS0001702112#tab_mapView

Irish distribution, National biodiversity data centre, in Mollusc Ireland: www.habitas.org.uk/molluscireland/species.asp?ID=121

 

Acknowledgements

I gratefully thank Ben Rowson of the National Museum of Wales/ Amgueddfa Cymru for his help with the account, but any errors or omissions are mine.

 

Links and references

 

Anderson, R. MolluscIreland, accessed January 2019. www.habitas.org.uk/molluscireland/species.asp?ID=121

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 4 (1853), 190 – 197 & plate CXXV. London, van Voorst. (AsConovulus denticulatus var. myosotis.)

Free pdf at archive.org/details/historyofbritish04forbe/page/190

plate at archive.org/details/historyofbritish04forbe/page/n565

 

Fretter, V. & Peake, J. 1975. Pulmonates functional anatomy and physiology. Vol.1. London. Academic Press.

 

Gittenberger, E. et al. 2004. De Nederlandse zoetwatermollusken. Leiden, Netherlands, Nationaal Natuurhistorisch Museum Naturalis.

 

Heller J. 2015. Marine Ancestors of most Land Snails: Pulmonates. In: Sea Snails. Springer, Cham. link.springer.com/chapter/10.1007%2F978-3-319-15452-7_10

 

Jeffreys, J.G. 1862-69. British conchology. vol. 5 (1869). London, van Voorst. (As Melampus myosotis (including var. ringens = Myosotella denticulata); Free pdf at archive.org/stream/britishconcholog05jeffr#page/106/mode/2up . Use slide at base of page to select pp.106-109.)

 

Martins, A.M. de F. 1996. Anatomy and systematics of the western Atlantic Ellobidae (Gastropoda: Pulmonata). Malacologia 37(2): 163 – 332.

www.biodiversitylibrary.org/page/13113594#page/179/mode/1up

 

Martins, A.M. de F. & Mendes, A.R.M. 2013. Do cosmopolitans speciate? Anatomical diversity of Myosotella in Azores. Centro de Investigação em Biodiversidade e Recursos Genéticos. Ponta Delgada, Açores, Portugal. Poster for World Congress of Malacology 2013 in pdf: www.researchgate.net/publication/264339925_Do_cosmopolita... .

 

Montagu, G. 1808. Supplement to: 1803 Testacea Britannica, or, Natural history of British shells, marine, land, and fresh-water, including the most minute : systematically arranged and embellished with figures. London, J. White.

Description of Leucophtia bidentata as Voluta bidentata pp. 100-101.

www.biodiversitylibrary.org/page/24430722#page/806/mode/1up

Plate 30, fig.2:

www.biodiversitylibrary.org/page/24430722#page/917/mode/1up

  

Morton, J. E. 1955. The functional morphology of the British Ellobiidae (Gastropoda Pulmonata) with special reference to the digestive and reproductive systems. Phil. Trans. R. Soc. Ser. B .

239, No. 661: 89-160 www.jstor.org/stable/92507

 

Schultes, F.W. 2014. Species summary for Ovatella myosotis (Draparnoud, 1801). AnimalBase. SUB Göttingen. www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBas... Accessed January 2019.

 

Watson, H. I943. Notes on a list of the British non-marine Mollusca. J. Conch. 22: 13 - 22.

 

Wiese, V. & Richling, I. 2008. Das Mäuseöhrchen Myosotella myosotis (Draparnaud 1801). Arbeitskreis Mollusken NRW.

www.mollusken-nrw.de/weichtier_des_jahres/weichtier2008.htm

 

Wondrak, G. 1984. Ultrastructure of the sensory epithelia of oral tube, fungiform sensory bodies, and terminal knobs of tentacles of Ovatella

myosotis. Draparnaud (Archaeopulmonata, Gastropoda) J. Morphol. 181: 333-347 .

onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.1051810307

 

Current taxonomy:

www.marinespecies.org/aphia.php?p=taxdetails&id=139673

 

Glossary

adapical angle = angle at which outer lip meets body-whorl.

boli = (sing. bolus) small rounded masses, especially of triturated food material.

cerebral = to do with integration of sensory and neural functions to initiate and coordinate body activity.

chalaziform = resembling the two spiral bands (chalazae) in a bird's egg that attach the yolk to opposite ends of the lining membrane.

 

columella = solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.

 

columellar = (adj.) of or near central axis of coiled gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

costa (pl. costae) = rib running across a whorl of a gastropod shell at approximately right-angles to direction of coiling and any spiral striae.

 

costal (adj.) = of, or arranged like, costae.

dextral = (of gastropod shell) in apertural view with spire uppermost, the aperture is on the right. Most gastropod species adults have dextral shells.

 

distal = away from centre of body or from point of attachment.

diverticula = (for digestion) blind ended tubules in the digestive gland that receive nutrients for digestion.

 

EHWS = extreme high water spring tide.

euryhaline = able to tolerate a wide variation in salinty.

fusiform = slender, spindle-shaped, tapering almost equally towards both ends.

 

ganglia = (sing. ganglion) knots on a nerve cord containing sensory cell bodies that conduct impulses to (innervate) organs of the body.

 

haemolymph = circulating fluid in molluscs that carries nutrients, waste and hormones. Analagous to vertebrate blood, but most molluscs have copper-based haemocyanin in it instead of red haemoglobin to carry oxygen. It may be tinged blue when oxygenated; colourless when depleted of oxygen.

 

halophyte = plant tolerant of saline soil and periodic tidal immersion, usually on saltmarshes, estuarine shores and sides of tidal rivers.

 

mantle = sheet of tissue that secretes the shell, covers the viscera and forms a cavity in gastropods. In terrestrial gastropods ('pulmonates') the cavity roof contains a network of haemolymph ('blood') vessels enabling the cavity to act like a lung.

 

mesial = on or facing towards the midline of the body.

operculum = plate of horny conchiolin, rarely calcareous, used to close shell aperture of prosobranch gastropods.

 

palatal lip = outer lip of gastropod aperture.

parietal lip ( or parietal wall) = upper part of inner side of gastropod aperture, often lacking clear lip structure with just a glaze on side of whorl adapically of columellar lip.

 

periostracum = thin horny layer of proteinaceous material often coating shells.

posteromesial = at the rear facing towards the midline of the body.

prosobranch = member of Prosobranchia, one of three subclasses into which the class Gastropoda (slugs and snails) was divided during the 20th Century (other two were Pulmonata and Opisthobranchia). This classification is no longer used by scientists, but prosobranch is a useful informal term to signify (mainly marine) snails breathing with a ctenidium (comblike gill inside mantle cavity), an operculum, and a shell which can accommodate the whole body.

 

protandrous hermaphrodite = each individual starts mature life as a functioning male, later changing to female function.

 

protoconch = apical whorls produced during embryonic and larval stages of gastropod; often different in form from other whorls (teleoconch).

 

protrusions = teeth, denticles, folds, lamellae or cogs (terms used by various authors).

 

punctate = with pinprick-like depressions.

resorb = absorb what was previously secreted; break it down into component materials and disperse into the circulation.

 

resorption = the process of absorbing what was previously secreted by breaking it down into component materials and dispersal into the circulation.

 

salting = area of salt tolerant vascular plants rooted in sediment between mean high water mark (MHW) and extreme high water of spring tides (EHWS). [Preferred synonym for “saltmarsh” as much of salting not marshy.]

 

septa = plural of septum; internal partition separating two chambers/ shell-whorls of a gastropod.

 

septum = internal partition separating two chambers/ shell-whorls of a gastropod.

 

sinistral = (of gastropod shell) in apertural view with spire uppermost, the aperture is on the left. Most gastropod species adults have dextral shells.

 

subsutural = close below the suture when shell positioned with apex uppermost.

 

subulate = slender and tapering to a point like onion leaf or awl.

suture = groove or line where whorls of gastropod shell adjoin.

teleoconch = entire gastropod shell other than the apical, embryonic & larval stage protoconch.

 

triturate = reduce to small particles.

vascular plants = plants that have vascular tissues to transport water and nutrients through the plant. Include all seed-bearing plants, ferns and horsetails. Usually terrestrial or in freshwater or brackish water; a few, such as Zostera, live in fully marine salinity water.

 

(This is one of the fenced-in rectangular area described in the notes below ... which the police have not yet allowed any visitors to venture into ... the view is looking north from approximately 43rd Street.

 

Note: this photo was published in an undated (Jan 3, 2011) Everyblock NYC zipcodes blog titled "10036." It was also published in a Nov 23, 2011 "Mother Jones" blog titled "Glossary: Decoding the Police Jargon Overheard at Occupy."

 

Moving into 2012, the photo was published in a Apr 3, 2012 blog titled "Documents show cops making up the rules on mobile surveillance."

 

***************************************

As I noted in this Flickr set a year ago, no New Yorker in his right mind goes to Times Square on New Year's Eve. Nobody from Manhattan, anyway -- you can never tell about those crazy people in the remote boroughs of Brooklyn, Queens, Staten Island, or the Bronx (and we won't even try to imagine what those crazy folks in New Jersey might do). Actually, even some residents of Manhattan have experienced the New Year's Eve count-down once in their lives, if only so they can speak with some authority about the subject. In my case, it was back in 1969; and it was only because I had had a pleasant dinner at a fancy restaurant a couple blocks from Times Square, and had to walk to the subway when no taxis could be found. There I was, in the midst of it all ... and once was more than enough.

 

Why do New Yorkers do their best to stay away from Times Square on New Year's Eve? Well, have you ever looked at a TV report from Times Square in the midst of all that mayhem? There are a gazillion other people out there, jammed against each other, shoulder to shoulder — and they're all drunk (or at least they look that way), and they're all screaming at the top of their lungs. You can't just drive to a nearby corner and park your car, with a plan of getting back in your car and fleeing after you've seen what a crazy idea it was. And you can't take a taxi right to the middle of Times Square — at least, not after mid-afternoon on New Year's Eve. Even worse, there are no public bathrooms anywhere to be found, so you're in trouble if you drink too much beer ... except that the cops do their best, quite understandably, to make sure nobody in the Times Square area (which, on this special night, is broadly defined to cover the area from 34th Street to 59th Street, and from Sixth Avenue to Eighth Avenue) is drinking or doing anything that might look dangerous. Or carrying a backpack that might contain dangerous things.

 

Consequently, it often seems that most of the crowd has chosen to get roaring drunk before they arrive on the scene. All of which might be great fun if the weather is clear, and the temperature is somewhere above the freezing mark. But if it's 30 degrees or lower, and it's drizzling or raining or snowing, this is not a place where you want to spend six or eight hours standing around with two million of your best (drunken) friends...

 

Thus, it should not surprise you to hear that I was not in Times Square to watch the ball drop at midnight on New Year's Eve of 2010 (or, for that matter, any other year going back to 1969). However, I remembered that my visit to Times Square in the early afternoon of Dec 31, 2009 had been somewhat interesting, and since the weather forecasters were predicting mild, mostly-sunny skies this year, I thought it might be interesting to try it again.

 

I took the IRT subway down to Times Square, and then spent the next two hours wandering north up Broadway to about 49th Street, and then back toward 42nd St. again. Even at 1:30 PM, the streets were already crowded with families and tourists, and what seemed to be an even larger number of police. It also seemed like almost everyone was wearing a party hat, or a set of "2011" fake eyeglasses, or some other kind of celebratory costume or adornment. There were also gazillions of digital cameras, and an equal number of Blackberries and cellphones. I wonder how many millions and millions of digital images and video clips were shot during the course of the afternoon.

 

Perhaps the funniest sight during the afternoon was the frequent appearance of delivery guys wearing bright, colorful, and instantly recognizable Domino's Pizza uniforms, wandering through the crowds with large, insulated "thermal" bags that probably carried half a dozen pizzas. In a couple cases, they were peering anxiously at individuals at a specific street corner; my assumption was that someone had called Domino's from their cell phone, requesting delivery to that exact spot. But in other cases, it looked far more likely that the delivery guys were just wandering around, looking for hungry people that were probably willing to pay a premium price for a good hot slice of pizza ... or the whole darn pie.

 

Around 2:45 PM, I was wandering south on Broadway once again, but when I got as far as 44th Street, I could see that the cops had completely closed off the next two blocks, and that even the sidewalks were impassable. I knew that they were cordoning the crowd into fenced-in rectangular areas, and that (a) each person allowed into such a rectangular area was first searched by a cop for booze, weapons or other contraband, and (b) once inside the fenced-in area, you weren't allowed out unless you left for good.

 

As more people arrived, the cops kept moving northwards, filling up one rectangular area after another. The obvious strategy for me, then, was to turn around and head north -- toward the local IRT subway stop at Broadway and 50th Street. But I got no further than 46th Street before everything stopped, and I could make no further progress along the sidewalk, even though I had been hugging the sides of the buildings along the way to avoid the throngs everywhere else. Fortunately, I was only about 10 feet from the corner of Broadway and 46th; but it took a good, solid 15 minutes to actually reach the corner -- at which point I heard the cops yelling to the crowd that they were closing everything down, and that anyone who wanted to go elsewhere would have to take the "side street" (i.e., 46th Street) over to 8th Avenue, in order to navigate further northward.

 

There were more barricades at 8th Avenue and 46th Street, and the narrow passageways onto 8th Avenue itself were being closed down. I managed to squeeze through, got onto 8th Avenue, and then easily walked up to 50th Street. Back over to Broadway, and I could look down the avenue all the way to the tower on 42nd Street where the ball would drop later tonight. And turning around, I could look several blocks north up Broadway, and see that (a) they were all empty, and (b) the cops had cordoned them off, too. By now, it was about 3:15 PM, and I got the sense that it wouldn't be long before the fenced-in crowds would be all the way up to where I was, and then further north, perhaps all the way up to Central Park at 59th Street.

 

In any case, it was clearly time to go home. I uploaded the 800+ photos that I had taken during the afternoon, enjoyed a delicious New Year's Eve dinner at home, and then settled down to watch the revelry on television as the countdown came to an end. As I noted at the end of last year's Flickr set of Times Square images, the TV coverage was obviously far more extensive than what I could accomplish with just one DSLR camera; and it was also infinitely more sophisticated, with high-end TV cameras located on strategic vantage points all around the square. On the other hand, the TV images appear, and then disappear, often leaving no lasting impression. By contrast, these still images will hopefully be interesting to look at months, if not years, from now. For better or worse, they'll be here whenever you'd like to see them...

 

field | work

 

Interweave Pattern

In Scots souter is 'a cobbler or shoemaker'. The feature to which it applies is a conspicuous tall, relatively thin coastal rock-stack. As discussed in the Elements Glossary, it is best known in the name The Souters, 'the two hills enclosing the entrance to the Cromarty Firth on the north and south, and resembling cobblers bent over their work. Cf. The Cobbler in Argyll' (SND). However, there is nothing bent over about the BWK Souter, so it may be that it is reminiscent of a shoemaker's needle. W. J. Watson, in his discussion of The Souters ROS (earliest form 'Craiges callit the Sowteris' 1593 APS), suggests rather Gaelic sùdaire 'a tanner' (1904, 126), but this is unlikely and unhelpful.

 

There is a Souter Head on the Kincardineshire coast (Nigg parish) south of Aberdeen, described in the OS Name Book as 'A bold rocky headland on the coast, opposite Burnbanks' (OS1/19/17/47). A comparative study of all these features would probably help explain the use of this element in coastal place-names.

 

Unfortunately the OS Name Book descriptive remarks on Souter and the related Souter Tails are obscured by a separate sheet extending the information on the preceding entry, Fast Castle. The original would have to be looked at, in the hope that the sheet has been attached only by its upper edge, and can therefore be lifted like a flap. All three informants seem to have given the form Suter and Suter Tails respectively, but the o has been added with a caret mark each time, while the approved OS Name Book forms are Souter and Souter Tails (OS1/5/9/17). A related name Souter Brae is described as follows: 'A steep brae bounding the sea shore contiguous to a rock called the Suter

Dense, dark brown cerata with white flecks cover most of body. Exposed notum is brownish yellow with densely spread, small, purplish brown and yellow flecks.

1: cleioproctic anus. 2: faecal mass. 3: tip of small triangular propodial tentacle.

Length 55 mm. Menai Strait, Wales. March 2010.

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/

PDF available at www.researchgate.net/publication/364340435_Aeolidia_papil...

 

Aeolidia papillosa (Linnaeus, 1761)

 

Synonyms: Limax papillosus Linnaeus, 1761; Eolis papillosa (Linnaeus, 1761).

 

Current taxonomy: World Register of Marine Species www.marinespecies.org/aphia.php?p=taxdetails&id=138709

 

Vernacular names: Common grey sea slug; Shag-rug aeolis; Plumed sea slug (English); Môrwlithen lwyd (Welsh); Stor trådsnegl (Danish); Vlokkige zeenaaktslak; Grote vlokslak (Dutch); Eolidien à papilles (French); Breitwartige Fadenschnecke (German).

 

GLOSSARY BELOW

 

Preface

In 2016, Kienberger et al. segregated with molecular sequencing what had previously been generally accepted in Europe as A. papillosa into Aeolidia papillosa sensu stricto (Linnaeus, 1761) and Aeolidia filomenae Kienberger et al., 2016. Descriptions published before 2016 combine features of the two species and often, such as in Alder & Hancock (1845-1855) fig. 31 flic.kr/p/2nRfmBr and Thompson & Brown (1984), illustrated the descriptions with images of probable A. filomenae. This account draws on the description in Kienberger et al. (2016).

 

Description

The large, broad and relatively low body sometimes grows to a maximum length of 120 mm. The ground colour of the notum varies from light white–beige, through mustard brownish, to reddish brown or dark brown with, often dense, darker flecks spread over it fig. 01 flic.kr/p/2nRf5eB & fig. 02 flic.kr/p/2nRgbPe .

Kienberger et al. (2016) state, “A white Y–shaped or triangular mark extending from the oral tentacles to the pericardial area between the rhinophores may be present.” (See appendix below for discussion of this). Dorsal surfaces are usually concealed by dense cerata apart from the head and a bare zone extending back from the rhinophores fig. 01 flic.kr/p/2nRf5eB & fig. 03 flic.kr/p/2nRbkGX .

The cleioproctic anus is located between the ninth and tenth row of the right side.

(fig. 04 flic.kr/p/2nRbkBr & fig. 01 flic.kr/p/2nRf5eB & Kienberger et al. 2016). The genital aperture is situated on the right side between the sixth and eighth anterior rows of cerata, which usually conceal it.

The numerous, crowded cerata are arranged in up to 25 close, difficult to discern, rows of eight to twelve cerata each, on each side of the body. They decrease in size towards the posterior of the body, and the anterior cerata positioned by the rhinophores are small fig. 05 flic.kr/p/2nRfnP6 . The cerata are often elongate and thin, with a uniform diameter for most of their length fig. 06 flic.kr/p/2nRdUp5 . Their dimensions can be altered but they are never flattened. They are translucent but usually covered with dark pigment marks and, sometimes, some white marks fig. 05 flic.kr/p/2nRfnP6 . Where the pigment is less intense, usually at the basal half of the posterior, the digestive gland may be visible fig. 07 flic.kr/p/2nRfnGH , and the dull whitish cnidosac is visible when not obscured by white apical pigment fig. 08 flic.kr/p/2nRdUkn . The general colour of individuals depends largely on the colour of the ceratal pigment, which is usually darker than the notum fig. 03 flic.kr/p/2nRbkGX but the peripheral cerata are sometimes pale fig. 09 flic.kr/p/2nRbkt5 .

The smooth, conical rhinophores are similar in colour to or a little darker than the body. The truncated tip usually has a small, terminal, translucent, pale spot fig. 10 flic.kr/p/2nRgvXT & fig. 11 flic.kr/p/2nRgvXh . The internal eye at the base of each rhinophore is rarely visible through the body, but may be discerned on some pale American specimens fig. 12 flic.kr/p/2nRfnCe .

The head has translucent, whitish, oral tentacles with variable amounts of dark and/or white freckling fig. 09 flic.kr/p/2nRbkt5 & fig. 10 flic.kr/p/2nRgvXT but the white does not form a well defined line. They are longer than the rhinophores and placed apart on the anterior edge of the head at a distance, when it is spread, equal to about three times the thickness of a tentacle base (IFS, pers. obs. fig. 10 flic.kr/p/2nRgvXT ).

The broad foot has small triangular propodial tentacles at the anterior fig. 10 flic.kr/p/2nRgvXT .

 

Key identification features Features vary and may sometimes overlap with similar species. Identifications should be made on the basis of more than a single feature. American specimens differ in some respects.

Aeolidia papillosa

Features as in Kienberger et al. (2016). [IFS pers. obs. in square brackets.]

1) Maximum length 120 mm.

2) Body colour extremely variable: from light white-beige, through mustard brownish, to reddish brown or dark brown.

3) “A white Y–shaped or triangular mark extending from the oral tentacles to the pericardial area between the rhinophores may be present”. [Pale marks on the head are frequent on A. papillosa in America fig. 13 flic.kr/p/2nRfnC4 , where A. filomenae is absent, but seem to be rare in Europe. See appendix below.]

4) Elongate thin cerata, not flattened, usually with uniform diameter for most of length fig. 06 flic.kr/p/2nRdUp5 . In difficult to count crowded rows.

5) Cerata darker than body.

6) [Dull whitish cnidosac visible if not obscured by white apical pigment fig. 08 flic.kr/p/2nRdUkn .]

7) Rhinophores dark, [usually with a small, terminal, translucent, pale spot on the truncated tip fig. 10 flic.kr/p/2nRgvXT & fig. 11 flic.kr/p/2nRgvXh ].

8) Internal eyes at base of rhinophores, visible rarely if ever in Europe. [Sometimes visible in America fig. 12 flic.kr/p/2nRfnCe ].

9) [Distance between oral tentacles at base about three times thickness of tentacle base, fig. 10 flic.kr/p/2nRgvXT ].

 

Similar species

Aeolidia filomenae Kienberger, Carmona, Pola, Padula, Gosliner & Cervera, 2016.

Features as in Kienberger et al. (2016). [IFS pers. obs. in square brackets.]

1) Longest specimen described in Kienberger et al. (2016) was 45 mm; maximum possible length not stated; at least 70 mm fig. 16 flic.kr/p/2nRbkeN .

2) Body white fig. 14 flic.kr/p/2nRgvUb , light beige, pink fig. 16 flic.kr/p/2nRbkeN or greenish with white or brown flecks [which may concentrate into dense brown on the head, rhinophores and pericardial area fig. 18 flic.kr/p/2nRgvAW ].

3) White ‘Y’ mark on oral tentacles and head, with stem passing back between the rhinophores, is often present. Varies from very evident and intense opaque white fig. 15 flic.kr/p/2nRgbpB to unobtrusive beige or light brown, and may be partly covered by white or beige flecks fig. 16 flic.kr/p/2nRbkeN . [See appendix.]

4) Cerata, [often in neat, easily counted rows], are typically flattened, broader at their base, and often slightly hooked inwards fig. 17 flic.kr/p/2nRfnk5 . This is the primary feature for identification (L. Carmona, pers. comm. 7 October 2022) [They may inflate a little to give a thicker cross section.]

5) Cerata usually [have much less surface pigment than on A. papillosa and] are usually lighter than the rest of the body fig. 15 flic.kr/p/2nRgbpB . [But some have dark cerata fig. 18 flic.kr/p/2nRgvAW .]

6) Apices of cerata are white, [often revealing large white cnidosacs fig. 15 flic.kr/p/2nRgbpB ].

7) Blunt, conical, smooth rhinophores are translucent whitish with opaque white or yellowish-white freckles which often concentrate to colour the distal quarter fig. 19 flic.kr/p/2nRbjYN . [Most also have brown spots of varying extent and intensity on the basal three-quarters fig. 18 flic.kr/p/2nRgvAW ]

8) Internal eyes sometimes faintly visible at base of rhinophores in lighter specimens fig. 19 flic.kr/p/2nRbjYN .

9) [Distance between oral tentacles at base about three times thickness of tentacle base. fig. 15 flic.kr/p/2nRgbpB ]

Pre 2016 authors such as Alder & Hancock (1845-1855) fig. 20 flic.kr/p/2nRfnd6 and Thompson & Brown (1984), illustrated their descriptions of A. papillosa with images of probable A. filomenae.

 

Aeolidiella alderi (Cocks, 1852) fig. 21 flic.kr/p/2nRgb6f , A. glauca (Alder & Hancock, 1845) fig. 22 flic.kr/p/2nRbjUz and A. sanguinea (Norman, 1877) fig. 23 flic.kr/p/2nRgvnQ .

1) Extreme maximum length 46 mm (A. sanguinea, others shorter).

2) Body translucent white or pale shade of other colour. Any opaque marks are scattered, small and not dark.

3) No white ‘Y’ or triangular mark on head.

4) Cerata not flattened, with uniform diameter for most of length

5) Cerata have more saturated colour than body.

6) Apices of cerata are white or pale.

7) Rhinophores translucent, no dark pigment marks.

8) Internal eyes visible at base of rhinophores

9) Distance between oral tentacles at base about same as thickness of single tentacle base (IFS pers. obs.).

 

Habits and ecology

Information in this section is mainly from Thompson & Brown (1984) who did not differentiate A. papillosa from A. filomenae, so it may apply to either one or both.

It lives sublittorally and on lower shores where there is some hard substrate, including estuaries down to 20‰ salinity and on muddy sand with isolated stones coated with sediment.

A. papillosa attacks and eats sea anemones, including Actinia equina and Metridium senile fig. 02 flic.kr/p/2nRgbPe . It is immune to the toxic nematocysts in their tentacles and exuded acontia fig. 24 flic.kr/p/2nRgvmn , and it ingests them and stores them in cnidosacs at the tips of its cerata for release when it is attacked. The effect is powerful enough in a dog's mouth to make it drop the slug (IFS pers. obs.) but it does not prevent haddock, Gadus aeglefinus, from consuming it (Thompson & Brown, 1984). Other enemies include copepod parasites and Nucella lapillus which occasionally eats its spawn. When alarmed it can raise its cerata and roll into a ball resembling a sea anemone fig. 25 flic.kr/p/2nRdTsa . Faeces are irregular masses fig. 01 flic.kr/p/2nRf5eB & fig. 04 flic.kr/p/2nRbkBr .

A. papillosa is a simultaneous hermaphrodite. Its convoluted white, pink or purple cord of spawn, somewhat resembling a coiled spring, is attached spirally to hard substrate from January to August in Britain. Initially, the coil forms a compact disc fig. 26 flic.kr/p/2nRgv6H but, as it ages, it absorbs water and expands into a looser coil fig. 27 flic.kr/p/2nRbjsT . When several individuals spawn close together, a confused mass may result fig. 28 flic.kr/p/2nRdTmo .

Veliger larvae hatch from the spawn and live in the plankton before metamorphosis. Small juveniles are not often found on shore; they may spend their early life sublittorally (Thompson & Brown, 1984).

 

Distribution and status

A. papillosa sensu stricto is an amphiboreal species with maximum uncorrected p-distance of 1.6% between individuals (Carmona et al., 2013), which is common along the Atlantic coasts of Europe and North America fig. 29 flic.kr/p/2nRbjqZ and from Washington State to Alaska in the in the north-eastern Pacific fig. 30 flic.kr/p/2nRfmFe . Kienberger et al. (2016) verified with molecular sequencing specimens from Sweden, Netherlands, Maine, Massachusetts, Alaska and Washington State. GBIF map www.gbif.org/species/2291938 . UK map NBN species.nbnatlas.org/species/NHMSYS0021312941

 

Acknowledgements

For use of images I gratefully thank Nils Aukan, Emil Burman, Roy Dahl, Jeff Goddard, Heine Jensen, Guillaume Lemonnier, Sutherland MacIver, Erin McKittrick, Malcolm Storey and Alex Wilson. For providing specimens to photograph I thank Simon Taylor. For information and advice I thank J. Lucas Cervera, Leila Carmona and Marta Pola, but any errors or omissions are my (IFS) responsibility.

 

Appendix

Kienberger et al. (2016) stated of A. papillosa, “A white Y–shaped or triangular mark extending from the oral tentacles to the pericardial area between the rhinophores may be present”. But the common practice of European recorders on iNaturalist and Facebook is to record all specimens with a white Y as A. filomenae.

As substantiation for their statement, Kienberger et al. refer to their Fig. 5B which shows a sequenced A. papillosa from the White Sea with a whitish mark on the head resembling a wine glass with the stem passing back between the rhinophores. Apart from it, the only European Aeolidia image with a wine glass mark found by IFS is one from the Mersey Estuary fig. 31 flic.kr/p/2nRfmBr . Whether the wine glass mark should be regarded as a form of white Y is an open question. Sometimes it is centrally faded with small lateral branches to resemble a Y, but the branches bend to meet at an obtuse angle of nearly 180° instead of the acute junction of the arms of a Y fig. 13 flic.kr/p/2nRfnC4 & fig. 29 flic.kr/p/2nRbjqZ .

Judging from the many images posted as A. papillosa on iNaturalist, and ‘Fig. 5F’ from Alaska in Kienberger et al. (2016), the wine glass mark is frequent on it in North America both in the Atlantic and Pacific. In the Pacific, it is often misidentified as A. loui Kienberger, Carmona, Pola, Padula, Gosliner & Cervera, 2016, especially in Washington and further north where there is no molecular evidence for A. loui ( L. Carmona, pers. comm. 7 October 2022).

Kienberger et al. differentiated A. papillosa and A. filomenae on the basis of molecular sequencing, and they described morphological features observed on the specimens studied which correlated with each species. It is possible that subsequent experience and photography of larger numbers have revealed more morphological variations but they need molecular sequencing for substantiation.

In June 2016, J. Lucas Cervera, co author with Kienberger, posted on Facebook Group N. E. Atlantic Nudibranchs to say that an in depth, focused study of UK and Irish specimens is still required to understand much better the diversity of this complex in that area, but that without material it is not possible. He would like collections to be made from different localities and then sent to him together in one or two packs, as if he receives the material scattered over time it is difficult to arrange students and material for a study focused on the issue. If you wish to help, please first email leila.carmona@uca.es for detail of how to preserve and send specimens.

Without further linked morphological and molecular study, morphological identifications of British and Irish Aeolidia species including those illustrated in this account are uncertain. Some specimens have some morphological features of each species fig. 32 flic.kr/p/2nSPveL and cannot be confidently identified without molecular sequencing; they are best recorded as Aeolidia sp.

 

References and links

Alder, J. & Hancock, A. 1845-1855. A monograph of the British nudibranchiate mollusca. London, Ray Society. Family 3 Plate 9 [A. papillosa sensu lato includes A. filomenae ] www.biodiversitylibrary.org/item/131598#page/314/mode/1up

 

Carmona, L., Pola, M., Gosliner, T. M. and Cervera, J. L. (2013) A tale that morphology fails to tell: a molecular phylogeny of Aeolidiidae (Aeolidida, Nudibranchia, Gastropoda). PLoS ONE 8(5): e63000. journals.plos.org/plosone/article?id=10.1371/journal.pone...

 

iNaturalist www.inaturalist.org/observations

 

Kienberger, K., Carmona, L., Pola, M., Padula, V., Gosliner, T.M. and Cervera, J.L. 2016. Aeolidia papillosa (Linnaeus, 1761) (Mollusca: Heterobranchia: Nudibranchia), single species or a cryptic species complex? A morphological and molecular study. Zool. J. Linn. Soc., 177: 481–506. www.researchgate.net/publication/303953645_Aeolidia_papil...

 

Thompson, T.E. & Brown, G.H. 1984. Biology of opisthobranch molluscs 2. London, Ray Society.

 

Glossary

acontia = thread-like tissue containing numerous stinging nematocysts which are released by some sea anemones.

amphiboreal = living in the cold temperate boreal zone to south of Arctic on more than one side of the Atlantic and/or Pacific.

 

cerata = (sing. ceras, adj. ceratal) lobes on notum of some nudibranchs.

cleioproctic = (of anus) located on the notum to the right of the midline.

Cnidaria = hydroids, jellyfish, sea anemones etc. which possess cnidocytes.

cnidocytes = explosive stinging cells of Cnidaria. en.wikipedia.org/wiki/Cnidocyte

cnidosac = storage capsule at tips of cerata of Aeolidiidae for ingested cnidocytes.

digestive gland = large organ in gastropods which acts like the liver and pancreas in mammals to absorb food.

 

distal = away from centre of body or from point of attachment.

hermaphrodite, simultaneous = individual acts as both male and female at the same time with similar partner.

 

molecular sequencing = technique for determining the sequence of the bases adenine, guanine, cytosine, and thymine (A, G, C and T) in a DNA molecule.

 

notum = (of sea slugs) the dorsal surface of the body; the back.

partim = partly, in part, a part, some of, some.

pericardium = sac containing heart, sometimes visible as a raised pericardial mound behind rhinophores in sea slugs.

pleuroproctic = (of anus) located on side of body below the notal edge or cerata.

propodial tentacles = tentacular, lateral extensions on anterior of the foot.

rhinophore = chemo-receptor tentacle; many sea slugs have a pair on top of the head.

sensu lato = (abbreviation s.l.) in the wide sense, possibly an aggregate of more than one species.

 

sensu stricto = (abbreviation s.s.) in the strict sense, excluding species that have been aggregated or confused with it.

 

veliger = shelled larva which moves by action of cilia on a velum (bilobed flap). Stage may be passed in plankton or within liquid-filled egg-capsule.

 

Same individual as in fig. 1 but with gills contracted (5) over the anal papilla, and anterior veil (mantle edge) lowered (1). Length 12.5 mm. Menai Strait, Wales. February 2011.

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/

 

Polycera quadrilineata (O. F. Müller, 1776)

 

Current taxonomy: World Register of Marine Species

www.marinespecies.org/aphia.php?p=taxdetails&id=140838

Until 2020 Polycera norvegica Sørensen, Rauch, Pola & Malaquias, 2020 was included within most published descriptions of P. quadrilineata.

Synonyms: Doris quadrilineata O. F. Müller, 1776; Polycera lineatus Risso, 1826; Polycera mediterranea Bergh, 1879;

GLOSSARY BELOW

 

Description

P. quadrilineata grows up to a maximum of about 30 mm long, extreme maximum 45 mm reported in literature (Sørensen et al., 2020). The body is translucent white, often revealing a dull orange or pinkish digestive gland below the gills, and a white buccal mass below the rhinophores fig. 1 flic.kr/p/2naUcNo . Its appearance varies with extension/contraction of its body and appendages fig. 1 flic.kr/p/2naUcNo & fig. 2 flic.kr/p/2naU5hm . The smooth surface has orange or yellow tuberculate blotches marking the rim of the reduced mantle in a line from below the rhinophores to the large single lobe at each side of the gills fig. 1 flic.kr/p/2naUcNo . The anterior of the rim often has triangular lateral projection fig. 3 flic.kr/p/2naMBL5 which sometimes is elongated and can be mistaken for a process on the anterior veil.

Almost all P. quadrilineata have yellow or orange on their appendages, on a dorsal line on the tail and on a variable number and size of scattered tuberculate blotches (not fine specks) fig. 3 flic.kr/p/2naMBL5 . In addition to the orange or yellow marks some have a few blackish marks (not fine specks) especially on the stems of the rhinophores fig. 4 flic.kr/p/2naMBHQ & fig. 5 flic.kr/p/2naVBWT . Other specimens have much more black pigment in lines fig. 6 flic.kr/p/2naT52C which sometimes resemble pin stripe fig. 7 flic.kr/p/2naSK3P and sometimes merge and mask the yellow or orange dorsal line on the tail fig. 8 flic.kr/p/2naMBEJ . The frequency of different colour combinations varies at different locations and with growth; the darker colours developing with age.

On the side of the animal, half way between the right rhinophore and gill there is a white genital aperture, most easily seen when in a contrasting black area fig. 9 flic.kr/p/2naT4YG . It sometimes has the white penis partially extended fig. 10 flic.kr/p/2naVBQk .

The rhinophores have a smooth, transparent, unpigmented basal third. The upper two thirds have a mean 10 to 12, range 6 to 17, lamellae; the lower ones are incomplete fig. 1 flic.kr/p/2naUcNo & fig. 3 flic.kr/p/2naMBL5 . The middle third of the rhinophore often flexes backwards, and the distal third flexes forwards. The distal lamellae usually have yellow or orange pigment which extends a variable amount down the anterior leaving the posterior translucent white. Some rhinophores have black pigment fig. 7 flic.kr/p/2naSK3P , especially on the smooth basal third fig. 4 flic.kr/p/2naMBHQ .

On the posterior slope of the swelling over the pericardium fig. 9 flic.kr/p/2naT4YG , which usually forms the highest point of the body, there is a fan of six or seven, sometimes up to eleven, unipinnate gill plumes fig. 11 flic.kr/p/2naSJWm . The anal papilla is located at the posterior of the fan’s base fig. 10 flic.kr/p/2naVBQk , fig. 11 flic.kr/p/2naSJWm & fig. 12 flic.kr/p/2naUcwm . On specimens with little or no dark pigment on the body, the gills are usually translucent white with yellow or orange tips fig. 1 flic.kr/p/2naUcNo , fig. 4 flic.kr/p/2naMBHQ & fig. 12 flic.kr/p/2naUcwm .Those with black on the body usually have darker colours such as brown on the shaft of the plumes fig. 10 flic.kr/p/2naVBQk & fig. 11 flic.kr/p/2naSJWm and dark shading on the vanes fig. 9 flic.kr/p/2naT4YG & fig. 11 flic.kr/p/2naSJWm . The gills do not retract into a pit, but they can contract into a small tight clump around the anal papilla fig. 12 flic.kr/p/2naUcwm or fold back over it fig. 13 flic.kr/p/2naT4R7 .When defecating, the fan can be held vertically to avoid fouling of the gills fig. 10 flic.kr/p/2naVBQk .

The edge of the mantle over the head is extended into an anterior veil with four or five, maximum seven, elongate yellow or orange processes fig. 3 flic.kr/p/2naMBL5 & fig. 6 flic.kr/p/2naT52C . On either side of the rounded oral area there is steep sided, oral rib which becomes a broad tapered structure when the mouth is pushed forward, level with or beyond the anterior veil fig. 14 flic.kr/p/2naT4P3 & fig. 15 flic.kr/p/2naSJNq .

The translucent white sole of the foot is truncate and broadest at the anterior with yellow-tipped, propodial tentacles fig. 16 flic.kr/p/2naUct5 . It tapers to a pointed posterior and readily folds along the midline fig. 17 flic.kr/p/2naVBCG . The dorsal, yellow or orange, medial line on the tail shows through the sole. Dorsally the foot is translucent white, often with a few small yellow marks fig. 9 flic.kr/p/2naT4YG .Viewed dorsally, the foot may be concealed by the body fig. 3 flic.kr/p/2naMBL5 , or may spread laterally into view fig. 18 flic.kr/p/2naSJJx .

 

Key identification features

P. quadrilineata

1) Most frequent lengths, (66%), 6 mm to 12.9 mm, max. 26 mm, in 30 measured in Korshunova et al. (2021). 45 mm max. reported in literature (Sørensen et al. 2020).

2) All have yellow/orange blotches fig. 3 flic.kr/p/2naMBL5 , and some also have blackish lines or marks (not just fine specks) fig. 6 flic.kr/p/2naT52C.

3) Anterior veil has, mean 4 or 5, max. 7 elongate processes fig. 3 flic.kr/p/2naMBL5 .

4) No elongate papillae protruding from base of rhinophores.

5) Lamellae on rhinophore: mean 10 to 12, range 6 to 17 (Sørensen et al. 2020 modified with data in Korshunova et al. 2021) fig. 3 flic.kr/p/2naMBL5 .

6) Single large, elongate, inclined backwards, yellow tipped process on either side of gills fig. 1 flic.kr/p/2naUcNo . Rarely in Britain, but less so in Norway, process is a compound lobe/flap with several summits/tubercles like that on P. faeroensis fig. 21.1 flic.kr/p/2pJZaiV .

7) Oral rib becomes a broad tapered structure when the mouth is pushed forward fig. 14 flic.kr/p/2naT4P3 (Caution, feature 7 observed on single specimen)

 

Similar species

Polycera norvegica Sørensen, Rauch, Pola & Malaquias, 2020 fig. 19 flic.kr/p/2naVBzA and fig. 20 flic.kr/p/2naMBjZ

1) Most frequent lengths, (69%), 5 mm to 7.9 mm, max.16 mm, in 32 measured in Korshunova et al. (2021).

2) Some fig. 19 flic.kr/p/2naVBzA have yellow/orange blotches like P. quadrilineata. Some fig. 20 flic.kr/p/2naMBjZ have a dense or sparse scatter of fine, blackish and/or brown specks (not strong black lines or blotches).

3) Anterior veil has mean of 4 or 5, maximum 6, elongate processes.

4) No elongate papillae protrude from base of rhinophores.

5) Lamellae on rhinophore: mean 8, range 6 to 11 (Sørensen et al. 2020 modified with data in Korshunova et al. 2021).

6) Single process either side of gills, often tipped yellow or a shade of orange darker than other yellow marks.

7) Oral rib becomes an un-tapered rounded structure when the mouth is pushed forward fig. 19 flic.kr/p/2naVBzA . (Caution, feature 7 observed on single specimen).

 

Polycera faeroensis Lemche, 1929 fig. 21 flic.kr/p/2naMBjd .

1) Maximum length 45 mm.

2) Yellow markings often only on appendages and dorsal line on tail. Some have yellow marks on body. None have blackish lines or marks.

3) Anterior veil has occasionally 6, but mean 8 or 9, maximum 14, elongate processes.

4) No elongate papillae protruding from base of rhinophores.

5) Lamellae on rhinophore: mean 18 to 19, maximum 25.

6) Compound lobe/flap with several summits/tubercles on either side of gills.

 

Polycera kernowensis Driessen, Picton & Martynov, 2021 fig. 22 flic.kr/p/2naSJCA .

1) Maximum length 20 mm.

2) Yellow markings confined to appendages and dorsal line on tail; no other coloured markings.

3) Anterior veil has mean 7 or 8, maximum 9, elongate processes.

4) No elongate papillae protruding from base of rhinophores.

5) Lamellae on rhinophore: mean 14 to 15, maximium 22.

6) Single process either side of gills, sometimes yellow tipped,

 

Trapania maculata Haefelfinger, 1960, T. pallida Kress, 1968 fig. 23 flic.kr/p/2naMBi1 & T. tartanella (Ihering, 1886) fig. 24 flic.kr/p/2naMBgn

2) White bodies with some opaque white, yellow or orange markings on some.

3) No elongate processes on anterior edge of head.

4) 1 or 2 backward pointing elongate papillae at base of each rhinophore.

6) Single elongate papilla on either side of the gills.

 

Ancula gibbosa (Risso, 1818) fig. 25 flic.kr/p/2naVBu5

1) Maximum length usually about 13 mm.

2) Yellow markings confined to appendages and dorsal line on tail; no other coloured markings.

3) No elongate processes on anterior edge of head (but has white oral tentacles).

4) 2 forward pointing elongate papillae at base of each rhinophore (can be mistaken for an anterior veil when viewed from above).

5) About 8 to 10 lamellae on rhinophore.

6) Several erect elongate papillae on either side of the gills.

 

Habits and ecology

P. quadrilineata lives at lower levels on rocky shores and sublittorally to 60 m. In North Wales it is usually largest and most easily found in February and March. It feeds on encrusting bryozoans, including Electra pilosa (often on Fucus serratus), Membranipora membranacea (often on Laminaria) fig. 18 flic.kr/p/2naSJJx , Callopora dumerilii, Celleporella hyalina and Tegella unicornis (Thompson and Brown, 1984).

It is a simultaneous hermaphrodite. The short, curved ribbon of spawn fig. 26 flic.kr/p/2naUcgG is attached by its edge near or on its prey on Fucus and Laminaria fronds and other algae in most months. Each mass contains about 20 000 small ova (Thompson & Brown, 1984). Shelled veliger larvae live as plankton before metamorphosing.

 

Distribution and status

P. quadrilineata occurs from arctic Norway to the Mediterranean, GBIF map www.gbif.org/species/2291758 . The GBIF map will include many records of mis-identified P. capitata made before its segregation was accepted. It is common, and sometimes abundant in early spring, on hard substrate shores all around Britain and Ireland, U.K. map,NBN, species.nbnatlas.org/species/NHMSYS0021316697 and many records lacking available images within the aggregate P. quadrilineata/capitata, made before 2020 when the segregation was accepted, are at species.nbnatlas.org/species/NHMSYS0021494705

 

Acknowledgements

I am indebted to Jim Anderson, David Fenwick and Stefan Verheyen for their generous provision of images for use in this account.

 

References and links

Alder, J. & Hancock, A. 1854. Notice of some new species of British Nudibranchiata. Ann. Mag. Nat. Hist. Second series vol 14, No. 79. pp.102–105 (1854) www.biodiversitylibrary.org/page/2283472 [Polycera capitata as Thecacera capitata].

 

Alder, J. & Hancock, A. 1845-1855. A monograph of the British nudibranchiate mollusca. London, Ray Society. Fam. 1 Pl. 22 www.biodiversitylibrary.org/item/131598#page/200/mode/1up

 

Anderson, J. (accessed March, 2022), Scottish Nudibranchs www.nudibranch.org/Scottish%20Nudibranchs/

 

Fenwick, D. (accessed March, 2022) Aphotomarine www.aphotomarine.com/

 

Korshunova, T.A., Driessen, F.M.F., Picton, B.E. & Martynov, A.V. 2021. The multilevel organismal diversity approach deciphers difficult to distinguish nudibranch species complex. Sci Rep 11, 18323 (2021). doi.org/10.1038/s41598-021-94863-5

Supplementary information

static-content.springer.com/esm/art%3A10.1038%2Fs41598-02...

 

Malaquias, M., Sørensen, C., Rauch, C., & Pola, M. (2022). Polycera norvegica is a valid species, and a plea for good taxonomic practices – a reply to Korshunova et al., 2021. Journal of the Marine Biological Association of the United Kingdom, 1-3. www.researchgate.net/publication/359931143_Polycera_norve...

 

Sørensen, C.G., Rauch, C., Pola, M. and Malaquias M.A.E. 2020. Integrative taxonomy reveals a cryptic species of the nudibranch genus Polycera (Polyceridae) in European waters. J. Mar. Biolog. Assoc. U.K. 1–20. Polycera capitata (Alder & Hancock, 1854) as P. norvegica sp. nov. doi.org/10.1017/S0025315420000612

also at

www.researchgate.net/publication/343321671_Integrative_ta...

 

Thompson, T.E. & Brown, G.H. 1984. Biology of opisthobranch molluscs 2. London, Ray Society.

 

Current taxonomy: World Register of Marine Species www.marinespecies.org/aphia.php?p=taxdetails&id=140838

 

Glossary

appendages = rhinophores, gills, lobes on anterior veil and lobes by gills.

buccal mass = organ system which includes the odontophore, radula, and a complex of muscles to operate them.

digestive gland = organ which acts like the liver and pancreas in mammals to absorb food.

dorid = a sea slug in the infraorder Doridoidei; with dorsal gills and rhinophores.

hermaphrodite, simultaneous = individual acts as both male and female at same time.

lamellae = (of sea slugs) small plates on rhinophores or leaflets of gill.

mantle = (of nudibranchs) sheet of tissue forming part or all of dorsal body surface.

anterior veil = anterior extension of mantle into a protruding sheet.

papilla = (pl. papillae) small, nipplelike protruberance.

pericardium = membranous sac containing heart.

propodium = anterior portion of gastropod foot. (adj. propodial).

rhinophore = chemo-receptor tentacle; many sea slugs have a pair on top of the head.

unipinnate = branching singly; boughs but no subsequent branches, like a feather.

veliger = shelled larva of marine gastropod or bivalve mollusc which moves by action of cilia on a velum (bilobed flap). Stage may be passed in plankton or within liquid-filled egg-capsule.

  

 

Shell length 19 mm, from animal 30 mm long. Wigham & Graham (2017) give maximum dimensions of shell 9 mm and animal 20 mm. This specimen far exceeds those limits (see 06Mp flic.kr/p/26MMpJ9 ). Llŷn Peninsula, Wales, March 2016.

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES:

www.flickr.com/photos/56388191@N08/collections/

 

Marsenia perspicua (Linnaeus, 1758)

 

Synonyms: Helix perspicua Linnaeus, 1758 ; Lamellaria perspicua (Linnaeus, 1758).

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=1505994

Vernacular: Groot glasmuitje (Dutch); kappeskael (Danish).

 

GLOSSARY below.

 

Introduction

M. perspicua is a dioecious caenogastropod, closely related to European cowries, Trivia spp. 1Mp flic.kr/p/KRSMkt , rather than a hermaphrodite heterobranch like the majority of seaslugs. But, having a concealed internal shell into which it cannot retreat, it qualifies as a 'seaslug', a vernacular, non-scientific term.

Shell description

The shell height (longest dimension) of M. perspicua is up to 20 mm 2Mp flic.kr/p/KRSL8i . It is weakly calcified, fragile and colourless semitransparent or clouded translucent 3Mp flic.kr/p/KRSKvg , and it is permanently covered by the fused right and left mantle lobes 1Mp flic.kr/p/KRSMkt . The periostracum is unobtrusive, very thin, transparent and slightly yellowed 4Mp flic.kr/p/KRSK5X . The very large body whorl forms over 90% of the shell. Two small, but rapidly expanding, spire whorls meet at a deep suture 3Mp flic.kr/p/KRSKvg . The shell is approximately ear-shape with a widely-open, very large, weak lipped aperture 5Mp flic.kr/p/KRSJJM . The inner (columellar and parietal) lip is slightly folded back. The small spire distinctly protrudes beyond the outer (palatal) lip of the aperture in apertural and abapertural view 3Mp flic.kr/p/KRSKvg & 5Mp flic.kr/p/KRSJJM . There is no sculpture except growth lines and, occasionally, some very faint spiral lines 4Mp flic.kr/p/KRSK5X . It is rarely washed up intact on the strandline. There is possible ambiguity over shell sizes in published accounts because of difficulty in measuring conventional height (apex to furthest point of aperture) of these fragile and unusually shaped shells, and perhaps identification confusion in collections of M. perspicua and Lamellaria latens shells. The longest dimension of the shell is usually half the length of the body, or slightly more. It has no operculum.

 

Body description

The maximum body-length is usually 20 mm (Graham, 1988); exceptionally it reaches 30 mm 6Mp flic.kr/p/26MMpJ9 . The shape of an individual can be varied between a moderate 7Mp flic.kr/p/MpVZgs or high dome 8Mp flic.kr/p/29tsc43 and a cone 9Mp flic.kr/p/MpVWuq . The fused mantle lobes often have large irregular tubercles, but the surface can be almost smooth 10Mp flic.kr/p/29tsaWU . Sometimes an outer layer of epidermis is sloughed ( Bate in Forbes & Hanley 1853), revealing fresh bright colours 11Mp flic.kr/p/28sgnwW and sometimes results in the loss of the majority of the sculpture and colour 12Mp flic.kr/p/29ts9Yw . The colours and patterning are extremely variable. The ground colours include lilac-grey 6Mp flic.kr/p/26MMpJ9 , buff 13Mp flic.kr/p/28sg8iq , whitish 10Mp flic.kr/p/29tsaWU , orange 8Mp flic.kr/p/29tsc43 and grey-brown 7Mp flic.kr/p/MpVZgs . The ventral surface of the mantle has just the ground colour with no pure white opaque marks 14Mp flic.kr/p/KRSDaR , but translucency may reveal markings on the dorsum 15Mp flic.kr/p/28sg6Mu . The dorsal surface often has marks of white, orange, yellow, black, and/or red (images 8Mp flic.kr/p/29tsc43 to 15Mp flic.kr/p/28sg6Mu ) which may cover almost all the ground colour and, frequently, mimic sessile animals such as ascidians 10Mp flic.kr/p/29tsaWU, sponges 15Mp flic.kr/p/28sg6Mu or barnacles 15Mp flic.kr/p/28sg6Mu . Sometimes, mobile organisms, such as juvenile Trivia seem to be mimicked 15.1Mp flic.kr/p/2hrtJKe . Occasionally, whitish M. perspicua 10Mp flic.kr/p/29tsaWU resemble Lamellaria latens with yellow marks near the edge of the mantle, and a fine black stipple with greyish discs mimicking Tridemnum.

The anterior edge of the mantle is curved into a cylindrical siphon with a cut along its anterior face, so it can be uncurled at times 16Mp flic.kr/p/MpVNGb . There are no gills or tentacles on the dorsal body surface. The mantle within the shell is thin, transparent and colourless so, when the shell is removed, the internal organs are clearly visible through it 17Mp flic.kr/p/29xyt7t .

The translucent head is coloured as the ground colour of the body with no pure white, opaque marks 14Mp flic.kr/p/KRSDaR . When not feeding, the head is flat and rectangular with long, slender, smooth cephalic tentacles on the anterior corners and no visible snout projecting between the tentacles. On the ventral face of the head there is an opening to a sac containing an inverted white proboscis, the straight, white, folded edge of which may be visible when the translucent head is well extended 14Mp flic.kr/p/KRSDaR . When ready to feed, the proboscis is engorged and everted from the slit 18Mp flic.kr/p/29tspU3 & 19Mp flic.kr/p/29xyM3P . The buccal mass and radula are within the proboscis.

As well as covering the shell, the mantle lobes extend beyond it to create a peripheral cavity which covers the head and foot. Within the shell, above the head and close to the respiratory siphon there is a respiratory mantle cavity with an opening restricted by the shell rim and mantle 18Mp flic.kr/p/29tspU3 & 20Mp flic.kr/p/29xyngv which contains a substantial, bright orange or brown, bipectinate osphradium and a large, pale orange or yellow, unipectinate ctenidium with very long filaments. A glimpse of the respiratory cavity and its contents may sometimes be had on a live specimen 18Mp flic.kr/p/29tspU3 , but dissection is required for a clear view 20Mp flic.kr/p/29xyngv .

The foot varies in shape from almost as wide as long to moderately long and narrow (Fretter and Graham, 1981) 21Mp flic.kr/p/28sfZDs . The broad, truncated anterior is bilaminate with the slit extending a short distance along the sides; the anterior pedal gland opens within it 22Mp flic.kr/p/26MMcjj . The upper lip of the slit may be corrugated. The dorsal surface of the foot is a similar colour to the ventral surface of the mantle 18Mp flic.kr/p/29tspU3 & 23Mp flic.kr/p/29trZb5 . The sole is paler than the mantle, often whitish becoming yellowish in parts that are compressed 21Mp flic.kr/p/28sfZDs , but on strongly coloured animals it may be a paler shade of the mantle ground colour 8Mp flic.kr/p/29tsc43 .

Males have a relatively enormous, pale penis attached behind the right tentacle 19Mp flic.kr/p/29xyM3P & 24Mp flic.kr/p/29trYwE . The substantial genital duct runs a long circuitous route before entering the base of the penis and emerges as a flagellum about a quarter of the way from the distal end of the penis 25Mp flic.kr/p/29trXLG . The distal quarter of the penis has a deep groove which accommodates much of the flagellum to give it support during copulation. The flagellum tapers to a fine point from which sperm emerge.

Further detail visible with simple dissection

The fused mantle lobes can be removed from over the concealed shell of an anaesthetized, relaxed and killed specimen with a sharp scalpel run around the edge of the shell. The translucent shell will be exposed and several internal organs will be partially visible through it 17Mp flic.kr/p/29xyt7t ; occasionally, this applies to a live sloughed specimen 17.2Mp flic.kr/p/28sg4s9 .

Removal of the shell will allow the organs to be clearly seen through the thin transparent mantle 17Mp flic.kr/p/29xyt7t . Items visible should include:

1: mantle skirt left after cutting; males will have a large penis below the skirt on the right of the animal.

2: respiratory siphon in mantle skirt.

3: bright orange or brown, bipectinate osphradium which tests the water quality of the inhalant current and, possibly, filters out large debris before the current reaches the ctenidium.

4: large, pale orange or yellow, unipectinate ctenidium (gill) with very long filaments.

5: white, left shell-muscle.

6: white, right shell-muscle.

7: white pericardial sac containing the heart.

8: convoluted hypobranchial band which shows as a series of irregular white bands on the mantle. It secretes mucus for trapping and cementing particulate matter from the inhalant current before it is expelled.

9: kidney.

10: (in females) oviduct consisting of:

a: genital aperture which penis of male enters, and from which capsules, each containing 1000 to 3000 ova, emerge.

b: capsule duct leading to genital aperture.

c: white mucoid cells at anterior of capsule gland.

d: capsule gland where capsule is formed around ova.

e: bright purple-pink posterior lobe of capsule gland.

f : albumen gland which produces albuminous fluid for nutrition of ova in the egg capsule.

g: ducts at the rear of the capsule gland receive sperm from the fine tip of the flagellum of the male's penis.

[ In this species the male's prostate gland is a narrow, unobtrusive tube, so does not feature prominently in the position occupied by the oviduct on females. Males have a large penis behind the right tentacle.]

11: ovaries (or testes in males).

12: round, white, acid producing, repugnatory glands in the mantle near the edge of the shell 17.1Mp flic.kr/p/26MMgvL .

Cutting the stricture at the entrance to the respiratory cavity will expose more of the ctenidium 20Mp flic.kr/p/29xyngv . Further cutting will release it to spread and show more detail of its lamellae 26Mp flic.kr/p/29trXuE .

Dissection of the proboscis (generally extruded if specimen is anaesthetised and relaxed) 26Mp flic.kr/p/29trXuE will expose the large whitish odontophore supporting a substantial colourless transparent radula, seen through the transparent radular sac which originates in a yellow, heart-shaped posterior end 26Mp flic.kr/p/29trXuE .

Opening of the body of a male should expose the substantial, convoluted genital duct that enters the base of the penis and emerges as a flagellum about a quarter of the way from the distal end 25Mp flic.kr/p/29trXLG .

 

Key identification features

Marsenia perspicua

1: maximum length when live usually 23 mm, occasionally 30 mm 6Mp flic.kr/p/26MMpJ9 .

2: mantle lobes fused; no dorsal break or joint visible.

3: dorsal surface varies from strongly tuberculated 7Mp flic.kr/p/MpVZgs to almost smooth 10Mp flic.kr/p/29tsaWU .

4: dorsal surface has wide range of colours and patterns 13Mp flic.kr/p/28sg8iq , including ones similar to L. latens 10Mp flic.kr/p/29tsaWU .

5: shape of live animal is moderate to high dome 7Mp flic.kr/p/MpVZgs or conical 9Mp flic.kr/p/MpVWuq .

6: ventral surface of mantle lobes includes pale shades of lilac-grey, buff, off-white, orange and grey-brown, not with pure white, opaque marks on ventral surface of mantle lobes or head 21Mp flic.kr/p/28sfZDs . Occasionally translucent enough to see from underside the overlying dorsal pattern 15Mp flic.kr/p/28sg6Mu .

7: short spire protrudes beyond outer lip of aperture when ear-shaped shell is viewed in plan 3Mp flic.kr/p/KRSKvg & 5Mp flic.kr/p/KRSJJM .

 

Similar species

Lamellaria latens (O. F. Müller, 1776)

Diagnostic features 6 & 7, of L. latens are not found on M. perspicua. Other features are usually found on L. latens, but sometimes also on the widely variable M. perspicua.

1: Maximum length when live 11 mm (6 to 8 mm frequent size).

!! Young M. perspicua can be under 11 mm length.

2: mantle lobes fused; no dorsal break or joint visible 32Mp flic.kr/p/MpVz3Y (both M. perspicua & L. latens).

3: Dorsal surface smooth to weakly tuberculated 31Mp flic.kr/p/28aM5Ht . !! Some M. perspicua can be also.

4: Dorsal colours mainly whitish or sandy, often with yellow flecks near mantle edge and fine black dots 31Mp flic.kr/p/28aM5Ht & 32Mp flic.kr/p/MpVz3Y .

!! Some M. perspicua have these markings 10Mp flic.kr/p/29tsaWU .

5: Individuals can vary their shape between a shallow bowl , inverted saucer 31Mp flic.kr/p/28aM5Ht and almost flat. !! M. perspicua though usually higher, can lower itself to a shallow bowl.

6: A few opaque bright white marks on translucent whitish head and/or semitransparent underside of mantle-lobes 32Mp flic.kr/p/MpVz3Y ). Often dorsal markings visible through the mantle lobes from below.

7: Spire of shell does not protrude beyond outer lip of aperture so shell outline is a smooth oval when viewed in plan 31Mp flic.kr/p/28aM5Ht .

 

Velutina plicatilis (O. F. Müller, 1776)

1: maximum length when live c.18 mm (excluding protruding foot and tentacles).

2: thick unfused mantle lobes can overlap a short way onto exterior of shell, but not sufficiently to cover it all 33Mp flic.kr/p/26MM2vw .

3: very weakly calcified, amber-brown shell consists mainly of periostracum 34Mp flic.kr/p/MpVxau which, when live, forms a velvety surface often mistaken for the mantle of Marsenia or a dorid seaslug 35Mp flic.kr/p/MpVy55 .

4: body and extended mantle lobes orange or yellow; (sometimes white, Graham, 1988). Shell is semi-transparent showing yellow/orange/brown viscera 33Mp flic.kr/p/26MM2vw .

5: active animal is egg-shape with a large flat foot, and tentacles on a snoutless head, but no external gills or siphon 35Mp flic.kr/p/MpVy55 .

7: shell has short spire which barely protrudes from the outline of the shell, and the apex is recessed below the previous whorl. Sutures, when not concealed by periostracum are deeper than on M. perspicua 34Mp flic.kr/p/MpVxau .

 

Trivia monacha (da Costa 1778) & Trivia arctica (Pulteney, 1779) juveniles.

1: maximum length when live 13 mm (excluding protruding foot and tentacles).

2 mantle lobes not fused; often withdrawn to expose juvenile white shell. If fully expanded, a dorsal break line is present 36Mp flic.kr/p/26MLZUW, but not always visible in photographs.

3 dorsal surface smooth or with papillae 36Mp flic.kr/p/26MLZUW & 37Mp flic.kr/p/28sfSph .

4 mantle dorsally whitish or yellowish-white; developing dark bands and/or marks as it matures 36Mp flic.kr/p/26MLZUW .

5 live animal spheroid.

7 juvenile shell is coiled and does not expose majority of interior.

 

Erato voluta (Montagu, 1803) 38 Mp flic.kr/p/2nbnESP

Strong shell, height 10 mm, retains exposed spire throughout life.

Stout inhalant siphon.

White spots on tentacles..

Two sides of dark, papillate mantle meet at dorsal median line, small gap shows white shell.

 

Habits and ecology

M. perspicua lives from LWS to 1200 m depth (Fretter & Graham, 1981) on or under stones and rock ledges, in rock pools and in Laminaria holdfasts near its compound or unitary ascidian prey, including Botryllus, Polyclinum, Leptoclinum and Trididemnum.

To feed the stout proboscis is everted 18Mp flic.kr/p/29tspU3 and its mouth applied to the ascidian for the radula to cut out pieces of test. Faeces are ovoid pellets.

For defence against predators, M. perspicua relies on its cryptic colouring which can resemble its ascidian prey 10Mp flic.kr/p/29tsaWU or other sessile organisms in its haunts such as encrusting red algae, barnacles 26.1Mp flic.kr/p/29trWQU and sponges 15Mp flic.kr/p/28sg6Mu , and on the ability of the mantle to secrete acid, highly distasteful to potential predators, when irritated 17.1Mp flic.kr/p/26MMgvL . The acid secreting glands are located near the edge of the shell where they would discourage invasion of the viscera contained within it.

Respiratory water enters the mantle cavity through an anterior siphon formed by a curling of the mantle. It passes through the large bipectinate osphradium which tests the water quality and may sieve out large detritus particles before the water reaches the large unipectinate ctenidium. The osphradium and ctenidium are in a small mantle cavity with a constricted opening 18Mp flic.kr/p/29tspU3 & 20Mp flic.kr/p/29xyngv .

Reproduction is in all months, with a maximum in spring and summer. The male passes its penis through the pallial oviduct 17Mp flic.kr/p/29xyt7t so that the slender distal flagellum 25Mp flic.kr/p/29trXLG can insert sperm into ducts at the posterior of the oviduct. Spherical capsules with a short neck 27Mp flic.kr/p/29trV2o are formed in the capsule gland of the oviduct and each filled with up to 3000 ova which have been fertilized with sperm stored in the ducts. The capsule receives albumen for nutrition of the ova from the adjacent albumen gland. The female bites a circular hole in the test of one of the compound or unitary ascidian prey species. Fretter & Graham (1962 & 1994) state, 'Velutina velutina favours the large solitary forms - - - while Marsenia eat compound ascidians', but both sorts are used for insertion of egg capsules by M. perspicua 27Mp flic.kr/p/29trV2o 28Mp flic.kr/p/26MM7Mo 29Mp flic.kr/p/28aM7RM & 30Mp flic.kr/p/26MM4Uu . When a filled capsule emerges from the oviduct it is inserted into the hole up to its neck by pressure of the foot, there being no specialised ventral pedal gland to aid this like that on closely related Trivia species. The neck with adhering ascidian is raised into a pronounced rim 28Mp flic.kr/p/26MM7Mo . When in encrusting compound ascidian with insufficient depth to accommodate the height of the capsule, the base of the capsule may be flattened to fit 27Mp flic.kr/p/29trV2o . On unitary ascidians with thicker tests, the only part of the capsule to protrude above the ascidian surface is the low dome of the translucent cap sealing the mouth and a slight rim 27Mp flic.kr/p/29trV2o . The capsules are translucent to semi-transparent, so the ova are often visible within. At room temperature, the ova hatch after about three weeks and, when covered in water, echinospira larvae are released from the capsule to drift in the water column. Initially, the larva has a velum of two lobes for maintaining position in the water column and capturing food. As the larva grows, each lobe subdivides so the velum becomes four-lobed and then six-lobed before the larva settles on the sea floor and metamorphoses into the adult form.

The anterior pedal gland within the widely bilaminate foot anterior 22Mp flic.kr/p/26MMcjj produces mucus to aid locomotion; there is no ventral pedal gland. As there is no central longitudinal groove on the sole, locomotor waves are probably monotaxic.

 

Distribution and status

M. perspicua is found from Iceland and the Lofoten Islands in northern Norway to the Mediterranean and Azores. GBIF map www.gbif.org/species/5192990 shows a more widespread distribution, but caution is needed as differentiating species of Marsenia is difficult; more species may be involved. It is widespread round Britain and Ireland where hard substrate and ascidians occur. It is scarce or absent from the north-eastern Irish Sea and from Flamborough Head to Kent. U.K. interactive map NBN records.nbnatlas.org/occurrences/search?q=lsid:NBNSYS0000...

 

Acknowledgements

For specimens and/or use of photographs I gratefully thank Karen Boswarva, George Brown, Jon Chamberlain, Paula Lightfoot, David McKay, Chris Rickard, Simon Taylor, Neil Ward and Steven Wouters.

 

Links and references

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853) 355-359, London, van Voorst. . archive.org/stream/ahistorybritish05forbgoog#page/n366/mo...

 

Fretter, V. 1946. The genital ducts of Theodoxus, Lamellaria and Trivia, and a discussion on their evolution in the prosobranchs. ;26(3): 312-351. J. mar. biol. Ass. U.K. plymsea.ac.uk/view/journals/Journal_of_the_Marine_Biologi... (Scroll down to Fretter, V. 1946).

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs: their functional anatomy and ecology. London, Ray Society. (Has index of species.)

 

Fretter, V. and Graham, A. 1981. The prosobranch molluscs of Britain and Denmark. Part 6 – Cerithiacea, Strombacea, Hipponicacea, Calyptraeacea, Lamellariacea, Cypraeacea, Naticacea, Tonnacea, Heteropoda. J. Moll. Stud. Suppl. 9: 285-363.

 

Fretter, V. and Graham, A. 1994. British prosobranch molluscs: their functional anatomy and ecology. Revised edition. London, Ray Society. (Much new material but lacks index of species.)

 

Graham, A. 1988. Molluscs: prosobranch and pyramidellid gastropods. Synopses of the British Fauna (New Series) no.2 (Second edition). Leiden, E.J.Brill/Dr. W. Backhuys. pp.662.

 

Høisæter, T. 2009. Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna norvegica 28: 5-106. www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/563

 

Jeffreys, J.G. 1862-69. British conchology. vol. 4 (1867) 234-238. London, van Voorst, archive.org/stream/britishconcholog04jeff#page/234/mode/2... ..

 

McKay, D. & Smith, S.M. 1979. Marine mollusca of East Scotland. Royal Scottish Museum, Edinburgh.

 

Wigham, G.D. & Graham, A. 2017. Marine gastropods 2: Littorinimorpha and other, unassigned, Caenogastropoda. Synopses of the British Fauna (New Series) no.61. (344 pages). Field Studies Council, Telford, England.

 

Glossary

aperture = mouth of gastropod shell; outlet for head and foot.

bipectinate = like a feather with a central axis and filaments or lamellae on either side.

Caenogastropoda = mostly sea snails able to completely withdraw body into shell but a few not, such as Marsenia seaslugs.

cephalic = (adj.) of or on the head.

columellar = (adj.) of or near central axis of spiral gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments or lamellae on one or two sides.

 

dioecious = (syn. gonochor[ist]ic) having separate male and female individuals, not hermaphrodite.

 

echinospira = special form of drifting larva with an inner and outer shell, the

intervening space filled with sea water.

 

ELWS = extreme low water spring tide (usually near March and September equinoxes).

 

everted = turned outside out and, like a sock, capable of turning outside in.

 

flagellum = (or filament) threadlike organ or appendage.

height = (of gastropod shells, as in most publications) distance from apex of spire to base of aperture but, as difficult to measure on Marsenia, the longest linear dimension is used in this account.

 

gonochor(ist)ic = (syn. dioecious) having separate male and female individuals, not hermaphrodite.

 

Heterobranchia = includes Nudibranchia and most species of sea slug with internal shell, but not Marsenia or Lamellaria.

 

inverted = (or introverted) turned outside in and, like a sock, capable of turning outside out (everted).

 

labial varix – especially strong or broad costa (rib) along or near outer lip of aperture.

 

leg. (abbreviation of legit) = 'he/she collected' i.e. collected/ found by (compare with coll.)

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs. Confined to the shell-interior of most British shelled-gastropods, but fused lobes of it cover exterior of shell of Marsenia.

 

monotaxic = (of locomotion waves on foot) single series of waves across complete width of foot.

 

operculum = plate of horny conchiolin, rarely calcareous, used to close shell aperture. Absent from Marsenia .

 

osphradium = organ for testing water quality (chemical and/or for particles) usually near ctenidium (gill).

 

papilla = (pl. papillae) small cone-shaped protrusion of flesh.

papillate = covered in papillae

periostracum = thin horny layer of chitinous material often coating shells.

plankton = animals and plants that drift in pelagic zone (main body of water).

proximal = towards the centre of the body or point of attachment.

sp. = abbreviation of 'species' singular. (The word 'species' is both sing. & pl.)

spp. = abbreviation of 'species' plural. (The word 'species' is both sing. & pl.)

suture = groove or line where whorls of gastropod shell adjoin.

test = (of ascidian) outer cellulose sheath containg zooid.

unipectinate = with central axis and series of filaments or lamellae on one side only.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (lobed flap).

 

vernacular = language spoken by ordinary people.

 

 

Copyright © by John Russell – All Rights Reserved

 

Kinetic Photograph made with one single long exposure shot. See more in: "The Best of Drawing with Light"

   

Body whorl 89% of shell height, so spire 11% (smaller % than spire on adults). Aperture 69% of shell height.

1: thin, fragile outer lip lacking any thickening indicates juvenile shell. (This juvenile is as big as some adults; use lip thickness, not size, to decide if a shell is adult or juvenile.)

2: distinct columellar lip, only on juveniles.

3: parietal lip not distinguished by glaze or other feature (but develops on adults) .

4: open umbilicus (sealed on adults).

Full SPECIES DESCRIPTION BELOW

Key id. features: flic.kr/p/2b9fTqj

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Cepaea hortensis (O.F.Müller, 1774)

Synonyms: Helix hortensis O.F.Müller, 1774; Helix nemoralis var. hortensis in Jeffreys.

GLOSSARY below.

 

Shell description

Usual size of adults from 10mm high X 14mm wide up to 17mm high X20mm wide 1Ch flic.kr/p/2b9fVXJ . Slightly depressed globular shell with convex whorls. Periphery of body whorl smoothly rounded; no keel. Small spire usually less than 20% of shell height 2Ch flic.kr/p/Nu31sR . No umbilicus on adults 3Ch flic.kr/p/2b9fTqj , but present on some juveniles 4Ch flic.kr/p/2caGbTQ .

Sculpture: shell smooth and glossy. Growth lines usually weak, but occasionally more pronounced one may give false impression of an umbilicus 1Ch flic.kr/p/2b9fVXJ .

Aperture height about 50% of adult shell-height, about 70% on juvenile; approximately D-shape on adult; more rounded on juvenile 2Ch flic.kr/p/Nu31sR . Palatal (outer) lip rounded in its upper part, turning sharply into its noticeably straight basal part. Very small columellar lip on adults 5Ch flic.kr/p/2cfhFsa but present on juveniles 2Ch flic.kr/p/Nu31sR . Parietal lip is a glaze on body whorl of older shells 3Ch flic.kr/p/2b9fTqj , imperceptible on juveniles 4Ch flic.kr/p/2caGbTQ

The palatal (outer) lip of adults has a white thickening and rib just within the rim 6Ch flic.kr/p/2caG9xh & 5Ch flic.kr/p/2cfhFsa . Externally, brown pigment usually does not extend onto the rim of the palatal lip; it is usually pale yellowish. The adult lip becomes everted, and at the base a short section may be reflected to expose some of the white inner face 5Ch flic.kr/p/2cfhFsa & 6Ch flic.kr/p/2caG9xh . Exceptions occur with a dark lip or slight dark flush on the white (Cameron, 2008), and juveniles have a thin fragile lip lacking any thickening or white 4Ch flic.kr/p/2caGbTQ . On live specimens the external ground colour of the opaque shell is usually some shade of glossy yellow 7Ch flic.kr/p/2cfhBFT with or without one to five brown spiral bands 1Ch flic.kr/p/2b9fVXJ , 6Ch flic.kr/p/2caG9xh & 8Ch flic.kr/p/2cfhzBn which occasionally merge 9Ch flic.kr/p/2aRrvKB , sometimes to give an entirely brown shell. The shell is whitish where the outer coloured surface is eroded to reveal the lower layer of shell or where extensive damage has been repaired 10Ch flic.kr/p/2cfhxWt as only the leading edge of the mantle at the aperture rim can create the glossy yellow outer shell layer/periostracum . Occasionally the bands are transparent without brown pigment. Internally, the shell has similar pattern to the exterior 1Ch flic.kr/p/2b9fVXJ .

 

Body description

External anatomy of extended specimen.

Apart from the smooth sole and ventral surface of the head, the entire exposed body is covered in closely-set, ellipsoid tubercles 9Ch flic.kr/p/2aRrvKB . Those on the flanks are arranged in approximately longitudinal lines slanting upwards towards the posterior 11Ch flic.kr/p/2aRrtJc . Translucent greyish white on flanks darkens to brown dorsally with a medial dorsal line of single, colourless, transparent tubercles 11Ch flic.kr/p/2aRrtJc . Viscera are sometimes indistinctly visible through the body wall 12Ch flic.kr/p/2cfhwTM ; the black internal continuation of the ocular tentacles and smaller anterior tentacles especially so. When the ocular tentacle is extended, the eye is positioned on a terminal, spherical bulb 11Ch flic.kr/p/2aRrtJc . The foot is widest at about half of its length from the head; rounded at the anterior; tapering to a rounded point at the posterior 13Ch flic.kr/p/2aRrsVD . Sole yellow, darkening to brownish when compressed to adhere strongly to substrate 14Ch flic.kr/p/2cfhw6p . Pneumostome sometimes visible within shell aperture on right 15Ch flic.kr/p/2cfhtCt & 16Ch flic.kr/p/2cfhtoa .

 

Functional internal anatomy:

Muscular system

The largest muscle is the white columellar muscle which connects the columella of the shell to the foot, and is used to draw the animal into the shell. It may be seen when the animal is first extracted from the shell 17Ch flic.kr/p/2cfhs3e . Many other muscles, such as those retracting the tentacles and buccal mass, run close to and join the columellar muscle; all need to be severed during dissection 18Ch flic.kr/p/Nu2MXa if the body is to be straightened out for examination.

The ocular tentacles 19Ch flic.kr/p/2cfhqGD , and other organs such as anterior tentacles, dart sac and penis 20Ch flic.kr/p/Nu2Ma8 are withdrawn into the body by the pull of retractor muscles that invert the organs like a sock pulled outside in 18Ch flic.kr/p/Nu2MXa . They are everted out of the body by muscles increasing the hydrostatic pressure in them of the haemolymph (invertebrate blood) which occupies the haemocoel (body cavity) free of confinement by veins or arteries.

Respiratory system

The mantle cavity is sealed by a yellowish collar of thickened mantle that has a pneumostome (respiratory pore) which can be opened for inhalation/exhalation of air 15Ch flic.kr/p/2cfhtCt & 16Ch flic.kr/p/2cfhtoa or closed to seal the cavity against dehydration. The transparent, sometimes spotted, roof of the mantle cavity contains a network of blood vessels 21Ch flic.kr/p/2cfhqkB and is very thin, enabling oxygen from inhaled air to diffuse into the vessels and for carbon dioxide to leave with the exhaled air. Air is moved in and out of the mantle cavity by the snail lowering and raising the floor of the mantle cavity 22Ch flic.kr/p/Nu2KLg to reduce or increase the air pressure in the cavity relative to that of the atmosphere. The oxygenated blood (haemolymph) is circulated to the rest of the body by the heart near the mantle cavity 22Ch flic.kr/p/Nu2KLg . Colourless haemolymph, depleted of oxygen, returns to the vascular roof of the mantle cavity via capillary vessels.

Alimentary system

The mouth is a transverse slit from which a radula emerges to rasp and gather food particles into the buccal cavity 23Ch flic.kr/p/2cfhnNn . The radula is a broad chitinous band covered with thousands of white teeth arranged in transverse rows 24Ch flic.kr/p/Nu2JiX . It is created within a white radula sac which is folded at the posterior where it protrudes from the rear of the buccal mass 25Ch flic.kr/p/2cfhmWT . The radula rests on a pair of cartilaginous bolsters 26Ch flic.kr/p/Nu2HJR , the odontophore, which support it as it is thrust back and forth. At its anterior, the radula emerges from the sac and flattens in readiness for use. A static red jaw with strong ribs is set into the top of the mouth 27Ch flic.kr/p/Nu2H3k ; it retains food loosened by the radula. Copious saliva to assist ingestion is brought to the buccal cavity and mouth from salivary glands by long salivary ducts 28Ch flic.kr/p/29tGHW5 . The short anterior tentacles, which can be retracted by inversion, are close to the mouth 29Ch flic.kr/p/Nu2FDP . When not feeding, the mouth is concealed behind a pair of lobe-like lips that open laterally, and the lips are flanked by lobes of the head 29Ch flic.kr/p/Nu2FDP . The buccal cavity leads to the oesophagus and subsequently to a wider, long, capacious crop alongside of which the large salivary glands are located 28Ch flic.kr/p/29tGHW5 . The crop leads to the narrower intestine which loops through the digestive gland 18Ch flic.kr/p/Nu2MXa , where digestion takes place, before joining the rectum along the right side of the body 28Ch flic.kr/p/29tGHW5 and ending at the anus which defecates into the mantle cavity. Conservation of water is important for land molluscs such as C. hortensis so faeces are quite dry 30Ch flic.kr/p/29tGGtf . Faeces and excreta leave the mantle cavity with the exhalent current out of the pneumostome.

Nervous system

Instead of a single brain C. hortensis, like other gastropods, has a series of ganglia (nerve knots) on a nerve cord that runs in a ring around the oesophagus 19Ch flic.kr/p/2cfhqGD with a dorsal and a ventral longitudinal extension towards the posterior on each side of the body 31Ch flic.kr/p/Nu2Fng . Each ganglion innervates a, usually proximate, specific part of the body. The cerebral ganglia on the nerve ring connect 32Ch flic.kr/p/2aRrm5K to the ocular tentacles, eyes and other parts of the head such as a subsidiary ring with ganglia around the buccal mass 26Ch flic.kr/p/Nu2HJR to control its feeding movements. The pedal ganglia on the ventral part of the nerve ring connect to the foot, and other regions of the body are connected to ganglia on the longitudinal extensions towards the posterior.

Reproductive system

[This section is based on Kerney & Cameron (1979) and Cameron (2008) except the part in italics which is based on Lodi & Koene (2016). The functions of love darts, the bursa copulatrix and diverticulum are not fully understood; some different hypotheses are mentioned below image 36Ch flic.kr/p/Nu2CR4 .]

C. hortensis is a simultaneous hermaphrodite. A mating couple approach each other face to face and try to manoeuvre into position to shoot a sharp dart of crystalline calcium carbonate 33Ch flic.kr/p/2aRrkHT & upload.wikimedia.org/wikipedia/commons/8/8e/Cepaea_horten... into the body wall of the other by forceful eversion of its containing dart sac 34Ch flic.kr/p/Nu2DXc . The dart is coated with mucus from a pair of 4-branched (sometimes 5-branched) mucus glands 34Ch flic.kr/p/Nu2DXc & 35Ch flic.kr/p/2aRrkqZ connected close to the opening of the dart sac. The penis 20Ch flic.kr/p/Nu2Ma8 of each is everted, like a sock turned inside out, through the atrium and out of the genital pore by hydrostatic pressure of haemolymph (blood). Each inserts its penis through the other's genital pore and atrium into its vagina 35Ch flic.kr/p/2aRrkqZ .

[The following two paragraphs are best understood if read from the caption below image 36Ch flic.kr/p/Nu2CR4 as numbers (1) to (17) refer to features in the image.]

Spermatozoa travel from the ovotestis (1) through the common duct (2 a.k.a. ovotestis duct or little hermaphrodite duct) to the albumen gland (3), thence through the prostate gland (4) and vas deferens (5) to the penis (6) where they are formed by its epiphallus (6e) and flagellum (6f) into a spermatophore (long thin package). The spermatophore is ejected through the everted penis into the other snail's vagina (7) 37Ch flic.kr/p/2aRrjXK . Fertilization is delayed for a few weeks, sometimes months, while a store of allosperm is accumulated in the diverticulum from couplings with other partners. To try to ensure that a single partner's sperm does not monopolize the fertilization, each allosperm deposit is reduced by the bursa copulatrix (8) digesting some of it on its transit from the vagina along the bursal duct (9) towards the diverticulum (10 small on this species). The insertion of a love dart from its sac (11) by the sperm-inserting partner earlier in the mating process partially counters the reduction of its allosperm contribution as the dart is coated from the mucus glands (12) with mucus containing chemicals that cause contraction waves in the vagina (7) which intermittently constrict the duct branch (13) to the bursa copulatrix (8), and increase the contractions of the diverticulum (10) which probably ease the passage of the spermatophore into it. Allosperm are stored in the diverticulum until required.

Ova pass from the ovotestis (1) through the common duct (2 a.k.a. ovotestis duct) to the albumen gland (3) 38Ch flic.kr/p/29tGBPL where they each receive a coating of nutrient albumen and move into the fertilization chamber (14). Stored allosperm are released to swim down the bursal duct (9) and up the oviduct (15) 37Ch flic.kr/p/2aRrjXK to fertilize the ova in the fertilization chamber. The fertilized ova then travel down the oviduct, through the atrium (16), and out of the genital pore (17) to be laid in a cavity excavated in the soil. Hatching occurs after some weeks; the period depending on temperature and humidity. Crawling miniature adults emerge as there is no larval stage.

 

Key identification features

 

Cepaea hortensis

Features in common with C. nemoralis (Linnaeus, 1758)

1. No umbilicus on adults 3Ch flic.kr/p/2b9fTqj , but present on some juveniles 4Ch flic.kr/p/2caGbTQ .

2. On adults, outer lip of aperture rounded in its upper part, turning sharply into a straight basal part. Juveniles differ. 2Ch flic.kr/p/Nu31sR .

Feature frequent on Cepaea hortensis, but sometimes on C. nemoralis

3. On adults, outer lip of aperture has a white thickening and rib just within the rim 6Ch flic.kr/p/2caG9xh & 5Ch flic.kr/p/2cfhFsa . Externally, brown pigment bands do not extend onto the rim of the lip; it is usually pale yellow. Lips on juveniles of both Cepaea spp. lack thickening, rib and colour distinction 2Ch flic.kr/p/Nu31sR . Care is needed not to mistake the pale mantle for a pale lip when sometimes reflected over and concealing the outer lip.

4. The red jaw has 2 to 4 strong ribs is set into the top of the mouth 27Ch flic.kr/p/Nu2H3k (Number has overlap with C. nemoralis which has 4 to 7 ribs.)

Reliable diagnostic features that differentiate C. hortensis from C. nemoralis

5. The love dart has four vanes that are thin at base and thicker and bifurcated distally, giving a cross section like a Maltese cross 33Ch flic.kr/p/2aRrkHT . But, the dart is very brittle and often missing. For examination, a stereoscopic dissecting microscope at c.X20 is needed.

6. A pair of 4-branched (occasionally 5-branched) mucus glands are connected close to the opening of the dart sac 34Ch flic.kr/p/Nu2DXc & 35Ch flic.kr/p/2aRrkqZ .

 

Similar species

 

Cepaea nemoralis

1. As 1 above for C. hortensis.

2. As 2 above for C. hortensis.

3. On adults, outer lip of aperture usually has a brown thickening and rib just within the rim 45Ch flic.kr/p/29tLEUA . But white lipped specimens occur 46Ch flic.kr/p/Q7eHQf . Lips on juveniles of both Cepaea spp. lack thickening, rib and colour distinction. Care is needed not to mistake the pale mantle for a pale lip when sometimes reflected over and concealing the outer lip.

4. The red jaw has 4 to 7 strong ribs (Hudson in Topley, 2006). Number has overlap with C. nemoralis which has 4 to 7 ribs.

5. The love dart has four vanes thickest at base and tapering steadily distally giving a cross section of a simple cross 47Ch flic.kr/p/2aRuFYg . But, the dart is very brittle and often missing. For examination, a stereoscopic dissecting microscope at c.X20 is needed.

6. A pair of 2-branched or 3-branched mucus glands are connected close to the opening of the dart sac 48Ch flic.kr/p/Q7eG9j . (In a Croatian study, two specimens with C. nemoralis type love darts had 4-branched glands (Štamol & Slapnik, 2015)).

7. maximum diameter 24mm, so Cepaea with diameter greater than 20mm (max. for C. hortensis) are most probably C. nemoralis 46Ch flic.kr/p/Q7eHQf . In mixed populations, C. nemoralis is usually obviously larger than C. hortensis.

Comment:

Relying for identification of a single specimen solely upon the feature suggested by the vernacular names "White-lipped snail" (C. hortensis) and "Brown-lipped snail" (C. nemoralis) can lead to misidentification. In areas where a species has not been previously recorded, several specimens should be examined and the mucus gland and love dart dissected before submitting the record to a recording scheme. The Pennine specimens illustrated in this account come from a garden where for 35 years C. hortensis was common, but C. nemoralis not seen until the hot dry summer of 2018 when 9 adults were found; 8 with brown lips and one with a white lip (love darts and mucus glands examined).

Special care is needed in continental Europe where further similar species occur. On the basis of lip colour, C. hortensis was regarded for over 150 years as living in Croatia. Recent fieldwork at its previously recorded sites failed to discover it, but found 6 white-lipped and 2 brown-lipped specimens with darts and mucus glands as described for C. nemoralis, casting doubt on the occurrence of C. hortensis in Croatia and possibly other Balkan areas (Štamol & Slapnik, 2015).

Habits and ecology

In moderately moist, sheltered habitats, including under leaf litter and stones, lush road verges, woods, rocks and gardens. Also on well drained maritime turf and sand dunes in cool, moist Scotland from the Firth of Forth northwards (Boycott, 1934).

The varied colours of the faeces 30Ch flic.kr/p/29tGGtf reflect the diet of mixed decaying organic detritus and soft living plant material. Feeding action is precisely controlled to maximize use of a food source with minimum effort or waste. On a piece of glass coated with dried flour paste the foot is attached firmly to hold the shell stationary 14Ch flic.kr/p/2cfhw6p . The head is extended and makes a stroke of the radula to rasp flour to the stationary jaw and into the mouth 23Ch flic.kr/p/2cfhnNn . The head is then moved slightly to the side and a second radula stroke made parallel and immediately adjacent to the first so it does not scrape any of the surface already dealt with, but leaves no waste between strokes except for a small triangle left by the narrowed tip. This is repeated until the head can swing no further. A timed swing of the head accommodated 15 radula strokes and took 23 seconds so each stroke and repositioning took c.1.5 seconds 39Ch flic.kr/p/29tGAgq . The animal then advances slightly so the next swing is on new food leaving no waste except a narrow strip containing the triangles formed by the radula tip. In captivity on horizontal glass, the snail shifted periodically to clear a rounded area. An area of paste about equal to the basal area of the snail was cleared every 6 minutes 40Ch flic.kr/p/2b9fsbw . In the wild the feeding pattern can be seen on alga-coated surfaces, but the area cleared is often linear. This was replicated when the sheet of glass was stood on edge and the snail worked upwards, suggesting that it is negatively geotaxic 41Ch flic.kr/p/29tLLt1 . However, observations of radula tracks in the wild 41.1Ch flic.kr/p/2c3kMNf (Craik & Anderson, 2018) show that the track of an unobserved gastropod species was linear with few radula strokes per head-swing on surfaces poor in alga not worth expending energy on, and changed immediately on reaching an alga-rich area to head swings five times wider with many more radula strokes per swing and a sinuous route, avoiding previously cleared tracks, to clear a non-linear patch of algae. In captivity on bare glass devoid of food, the radula of C. hortensis was not extended 29Ch flic.kr/p/Nu2FDP .

Activity is mainly nocturnal, avoiding dehydration and visual predators by spending daylight hours under stones or dense vegetation. They may be active in the open during daylight in humid weather without drying wind, sometimes with adverse results; on a humid morning two jackdaws cleared some garden steps of about 20 specimens in a few minutes, swallowing them whole. C. hortensis and C. nemoralis are the preferred molluscan food of thrushes (Boycott, 1934); piles of smashed shells are found around stones used as their “anvils” (image by G. Watson flic.kr/p/9yNrQD ) . Similar “middens” with many Cepaea shells are left by field mice and voles which bite open the spire, avoiding the reinforced aperture lip 42Ch flic.kr/p/Q7eLdG .

Water passes readily in and out of the highly permeable tissues and organs of molluscs so conservation and control of water are important for C. hortensis and other land molluscs. The principal source is osmotic absorption by the body and superficial mucus from wet and damp surroundings (Machin in Fretter and Peake, 1975), but water is also extracted efficiently from food so faeces are fairly dry 30Ch flic.kr/p/29tGGtf . Some water is lost with urine brought from the kidney by the ureter 21Ch flic.kr/p/2cfhqkB to the mantle cavity close to the anus. Faeces and excreta leave the mantle cavity through the pneumostome. If the body surface becomes dry, water is transferred to it in exuded mucus. Much water is lost with foot mucus during locomotion 29Ch flic.kr/p/Nu2FDP & 43Ch flic.kr/p/29tLFVJ , so the snail reduces loss in dry conditions by retracting into the shell and ceasing movement. Activity also usually ceases in heavy rain when the body may become over hydrated or the mucus over diluted (Boycott, 1934; Machin in Fretter and Peake, 1975). In very dry weather, the snail retracts into the shelter of the non-permeable shell, seals the entrance with a transparent, elastic epiphragm made of a film of dried mucus 44Ch flic.kr/p/Q7eKaj and may aestivate.

Locomotion is by monotaxic, direct, compression waves on the sole. On C. hortensis each wave is almost as wide as the sole, leaving only a narrow strip along each side that is not involved in the muscular waves. When travelling on glass, 3 or 4 transverse waves at a time may be discerned as slightly darker bands moving forwards on the sole 43Ch flic.kr/p/29tLFVJ . The bands are concave and raised slightly from the substrate. Though faint, their movement makes them more obvious when seen in action. Copious mucus is exuded by the foot to provide a film for it to move over.

Longevity: unlike most smaller species which have an annual life cycle, Cepaea hortensis can live longer; annual growth lines on adults often suggest a lifespan of about 3 years 7Ch flic.kr/p/2cfhBFT .

 

Distribution and status

Mainly North-West Europe: southern Scandinavia (Arctic Circle on coast of Norway) to Mediterranean coast of France and Mallorca, but scarce/absent on other Mediterranean coasts; east to Germany and Austria with a few records further east in Poland and Hungary, and a group of records in southern Finland, Estonia and Latvia. Probably scarce/absent in the Balkans. Introduced into North America; mainly Newfoundland to the Great Lakes and New York. GBIF map www.gbif.org/species/2294279 . Widespread and common in Britain up to Shetland, except for acid uplands in Scotland and Wales and historically, acidically polluted southern Lancashire; U.K. interactive map NBN records.nbnatlas.org/occurrences/search?q=lsid:NHMSYS0020...

 

Acknowledgements

I gratefully thank Clive Craik and Linda Pryke for use of their images, and Ben Rowson of the National Museum Wales for help in interpreting anatomical images, but any errors are my responsibility.

 

Links and references

Bargmann, H.E. 1930. The morphology of the central nervous system in the Gastropoda Pulmonata. J. Linn. Soc. (Zool.) 37 (250): 1 to 59.

 

Block, M.R. 1967. Dissecting Snails. Papers for students no. 8. London, the Conchological Society of Great Britain and Ireland.

 

Boycott, A.E. 1934. The habitats of land mollusca in Britain. J. Ecol. 22: 1 to 38.

Cameron, R. 2008. Land snails in the British Isles. Telford, Field Studies Council.

 

Cordero, A.M. (accessed October 2018) The phylogenetic distribution of darts in helicoid land snails. University of California, Berkeley.

www.ucmp.berkeley.edu/museum/75th/ab8.html

 

Craik, C. & Anderson, P. 2018. Fine art on a flat roof. Mollusc World 48: 26 – 27.

 

Fretter, V. & Peak, J. 1975. Pulmonates, functional anatomy and physiology. London, Academic Press.

 

Hudson, B. in Topley, P. 2006. Baker Hudson and some notes on Cepaea. Mollusc World 11: 8.

 

Janus, H. 1965. The young specialist looks at molluscs. London, Burke.

 

Jeffreys, J.G. 1862-69. British conchology. vol. 1 (1862). London, van Voorst. As Helix nemoralis var. hortensis Free pdf at archive.org/stream/britishconcholog01jeffr#page/184/searc... . Use slide at base of page to select pp.185 to 188.

 

Kerney, M. & Cameron, R. 1979. A field guide to the land snails of Britain and north-west Europe. London, William Collins.

 

Koene, J.M. and Schulenburg, H. (Mating) A love-dart at the heart of sexual conflict in snails. [Scanning Electron microscope of love dart of C. hortensis][CC BY 2.0 (creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

commons.wikimedia.org/wiki/File:Cepaea_hortensis_SEM_dart...

 

Lodi, M. & Koene, J.M. (2016) On the effect specificity of accessory gland products transferred by the love-dart of land snails. BMC Evolutionary Biology 16: 104. pdf at bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-016...

 

Pfleger, V. 1998. A field guide in colour to molluscs. Leicester, Blitz Editions.

 

Silverside, A.J. Lastdragon.org Biodiversity reference. Cepaea nemoralis (L.) Grove snail and Cepaea hortensis (O.F. Müll.) White-lipped snail. Accessed October 2018. bioref.lastdragon.org/Mollusca/Cepaea.html

 

Štamol, V. & Slapnik, R. 2015. Cepaea hortensis (O. F. Müller, 1774)

(Mollusca: Gastropoda) in Croatia? Nat. Croat. 24 (2): 331 to 336.

pdf at hrcak.srce.hr/file/220664

 

Zając, K.S. & Kramarz, P. 2017. Terrestrial gastropods - how do they reproduce? Invertebrate Survival Journal 14:199-209

pdf at www.researchgate.net/publication/317212919_Terrestrial_ga...

 

Current taxonomy: (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=1002172

 

Glossary

aestivate = to become dormant with a low metabolic rate, similar to hibernation, in response to warm, dry conditions.

alimentary system = organs for ingestion, digestion and absorption of food and the discharge of residual waste.

allosperm = sperm received from another individual. (Term used to avoid ambiguity of origin when discussing hermaphroditic reproduction.)

aperture = mouth of gastropod shell; outlet for head and foot.

atrium (genital) = cavity within genital pore leading to reproductive organs.

buccal mass = anterior of digestive system including an odontophore that supports anterior of radula, and a complex of muscles to operate them and other mouthparts.

bursa copulatrix = (a.k.a. spermatheca) copulatory pouch or sac for receiving allosperm for storage or partial consumption (sources differ on function; see caption of 36Ch flic.kr/p/Nu2CR4 ).

capillary vessels = fine branching blood vessels.

cartilages = (in gastropods) structures of tough, resilient material, histologically resembling vertebrate cartilage, embedded in tough connective tissue of left and right bolsters of the odontophore. Support and maintain shape of odontophore, and provide attachment for muscles controlling its movement.

 

cartilaginous = made of, or resembling, cartilage.

cerebral = to do with integration of sensory and neural functions to initiate and coordinate body activity.

chitin = semitransparent flexible horny protein.

chitinous = made of chitin.

columella = solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.

 

columellar = (adj.) of or near central axis of spiral gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

common duct = (a.k.a. ovotestis duct or little hermaphrodite duct) duct in hermaphrodite species from ovotestis to the albumen gland and/or prostate gland.

ditaxic = (of locomotion waves on foot) double series of waves, out of phase with each other, one series on each side of central furrow on sole.

 

direct = (of locomotion waves on foot) waves travel from posterior to anterior.

distal = away from centre of body or from point of attachment.

diverticulum(of bursal duct) = blind ended branch from the bursal duct for receiving allosperm for storage or partial consumption/processing (sources differ on function; see caption of 36Ch flic.kr/p/Nu2CR4 ).

 

epiphallus = extension of penis between the retractor muscle and junction of the vas deferens with the penis (strictly, an enlarged section of the vas deferens). Where body of spermatophore is formed.

everted = turned outside out and, like a sock, capable of turning outside in (inverted).

flagellum = long whiplike extension beyond the epihallus. Where the tail of the spermatophore is formed.

ganglia = knots on a nerve cord.

ganglion = a knot on a nerve cord.

haemocoel = system of interconnected spaces (sinuses) containing blood within body of a mollusc.

 

haemolymph = invertebrate blood.

height = (of gastropod shells) distance from apex of spire to base of aperture.

innervate = to arouse or stimulate a nerve or an organ to activity.

little hermaphrodite duct = (a.k.a. common duct or ovotestis duct) duct in hermaphrodite species from ovotestis to the albumen gland and/or prostate gland.

 

love dart = (a.k.a. gypsobelum) sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs stab each other during courtship. See 33Ch flic.kr/p/2aRrkHT and 36Ch (caption) flic.kr/p/Nu2CR4 .

 

mantle = sheet of tissue that secretes the shell and forms a cavity. In terrestrial gastropds ('pulmonates') the cavity roof contains a network of blood vessels enabling the cavity to act like a lung.

 

medial = midline of body or organ.

median = at/near centre of body as opposed to the sides.

monotaxic = (of locomotion waves on foot) single series of waves across complete width of foot.

ocular = of or connected with the eyes.

 

osmosis = movement of water or a solution through a selectively permeable membrane into a region of more concentrated solution, tending to equalize the concentration on either side of the membrane.

 

oviduct = internal duct to carry ova to the exterior.

ovotestis = hermaphrodite organ serving as both ovary and testis.

ovotestis duct = (a.k.a. common duct or little hermaphrodite duct) duct in hermaphrodite species from ovotestis to the albumen gland and/or prostate gland.

 

palatal lip = outer lip of gastropod aperture.

parietal lip ( or parietal wall) = inner side of gastropod aperture, often lacking clear lip structure with just a glaze on side of whorl adapically of columellar lip.

 

periostracum = thin horny layer of chitinous material often coating shells.

periphery = perimeter of the body whorl of a gastropod at its widest. Sometimes marked by a keel or coloured band.

 

odontophore = firm, usually medially grooved, approximately ellipsoid structure of cartilage supporting radula. Protruded like a tongue to operate radula. .

 

pneumostome = closeable breathing pore or respiratory opening in mantle of a pulmonate slug or snail.

 

prostate gland = gland that adds material to spermatozoa travelling through it to form semen.

 

proximal = towards the centre of the body or point of attachment.

proximate = very close to.

pulmonate = member of Pulmonata, one of three subclasses into which the class Gastropoda (slugs and snails) was divided during the 20th Century (other two were Prosobranchia and Opisthobranchia). This classification is no longer used by scientists, but pulmonate is a useful informal term to signify terrestrial slugs and snails, and freshwater snails, breathing atmospheric air through the lining of the mantle cavity, and with no operculum. There are also several freshwater and land prosobranchs. See en.wikipedia.org/wiki/Pulmonata

 

radula = ribbon of chitin bearing chitinous teeth that is extruded on a tongue-like odontophore of cartilage to rasp food.

 

spermatophore = a package made of mucoprotein containing an ejaculation of semen; created in the epiphallus and flagellum during copulation.

 

umbilicus = cavity up axis of some gastropods, open as a hole or chink on base of shell, often sealed over.

ureter = duct by which urine passes from the kidney out of the body.

vas deferens = tube carrying sperm to the penis.

vascular = relating to, containing or consisting of a vessel or vessels, especially those carrying blood.

 

Typical pedon.—A specific pedon description chosen to represent a map unit component as it occurs in a soil survey area. It is used in the correlation process to classify, name, and interpret the component. The pedon description, along with information about the soil’s overall range in characteristics, landscape setting, and other pertinent information, is included in the soil survey publication and/or database. The typical pedon is not a composite description based on a collection of pedon descriptions, but rather it is a real pedon with a physical location that can be revisited (also called a type location). See correlation, soil.

 

Figure 118.—The typical pedon of a soil series represents the soil as mapped within a particular soil survey area. Differing typical pedons may be identified in numerous soil survey areas across the series geographic area of extent or they may be shared across soil survey area boundaries. For example, Cecil soil (fine, kaolinitic, thermic Typic Kanhapludults) has been correlated in many soil surveys from Alabama to Virginia. Each typical pedon may have a slightly different description, but all are within the range of characteristics for the Cecil series unless noted.

  

An image of a cross-section of a cell from NHGRI’s Talking Glossary of Genetic Terms, updated in 2009.

www.genome.gov/Glossary/

 

Credit: National Human Genome Research Institute, National Institutes of Health

This early Arkham House anthology of works by H. P. Lovecraft includes such fantasies as "The White Ship" and the novel, "The Dream-Quest of Unknown Kadath," and such horror stories as "The Moon Bog," "The Unnamable," and the novel, "The Case of Charles Dexter Ward." There are poems and collaborations and revisions by Lovecraft, including "The Diary of Alonzo Typer," "The Curse of Yig," "The Mound," "The Horror in the Museum," and others. To the writings by Lovecraft himself have been added a "Cthulhu Glossary," by Francis Laney, designed to summarize what is known about the fabled beings and places of Lovecraft's monumental creation, the "Cthulhu Mythos."

Vanessa cardui is the most widespread of all butterfly species. It is commonly called the painted lady, or formerly in North America the cosmopolitan.

 

Description

For a key to the terms used, see Glossary of entomology terms.

See also: Cynthia (butterfly) § Distinguishing features

 

Wing scales.

Male and female. Upperside. Ground-colour reddish-ochreous, basal areas olivescent-ochreous-brown; cilia black, alternated with white, Forewing with an outwardly-oblique black irregular-shaped broken band crossing from middle of the cell to the disc above the submedian vein; the apical area from end of cell and the exterior border also black; before the apex is a short white outwardly-oblique streak and a curved row of four round spots, the second and third being small; a marginal pale lunular line with its upper portion most defined and whitish. Hind-wing with a blackish patch from the costal vein across end of cell, a partly confluent recurved discal band, a submarginal row of lunules, and then a marginal row of somewhat scutiform spots; between the discal band and submarginal lunules is a row of five round black spots, which in some examples show a pale and dark outer ring. Underside. Forewing brighter reddish-ochreous, the apical area and outer margin much paler, the apex being olivescent ochreous-brown; discal irregular band as above, subapical white streak, row of spots and marginal lunules distinct; base of wing and interspace before end of cell white. Hindwing transversely-marbled with olivescent ochreous-brown and speckled with black scales; crossed by basal and discal sinuous whitish or pale fascia and intersected by white veins; an outer-discal row of five ocelli, the upper one smallest and usually imperfect, the second and fifth the largest, the fourth with black centre speckled with blue and ringed with yellow, and the second and fifth also with an outer black ring; submarginal lunules purpurescent-grey, bordered by a whitish fascia; outer margin ochreous. Body olivescent ochreous-brown, abdomen with ochreous bands; palpi blackish above, white beneath; body beneath and legs greyish-white; antennae black above, tip and beneath reddish.

 

Distribution

V. cardui is one of the most widespread of all butterflies, found on every continent except Antarctica and South America. In Australia, V. cardui has a limited range around Bunbury, Fremantle, and Rottnest Island. However, its close relative, the Australian painted lady (V. kershawi, sometimes considered a subspecies) ranges over half the continent. Other closely related species are the American painted lady (V. virginiensis) and the West Coast lady (V. annabella).

 

Migration

V. cardui occurs in any temperate zone, including mountains in the tropics. The species is resident only in warmer areas, but migrates in spring, and sometimes again in autumn. It migrates from North Africa and the Mediterranean to Britain and Europe in May and June, occasionally reaching Iceland,[8] and from the Red Sea basin, via Israel and Cyprus, to Turkey in March and April. The occasional autumn migration made by V. cardui is likely for the inspection of resource changes; it consists of a round trip from Europe to Africa.

 

For decades, naturalists have debated whether the offspring of these immigrants ever make a southwards return migration. Research suggests that British painted ladies do undertake an autumn migration, making 14,500 km (9,000 mi) round trip from tropical Africa to the Arctic Circle in a series of steps by up to six successive generations. The Radar Entomology Unit at Rothamsted Research provided evidence that autumn migrations take place at high altitude, which explains why these migrations are seldom witnessed. In recent years, thanks to the activity of The Worldwide Painted Lady Migration citizen science project, led by the Barcelona-based Institute of Evolutionary Biology (Catalan: Institut de Biologia Evolutiva), the huge range of migration has begun to be revealed. For example, some butterflies migrated from Iceland to the Sahara desert, and even further south.

 

V. cardui is known for its distinct migratory behaviour. In California, they are usually seen flying from north to north-west. These migrations appear to be partially initiated by heavy winter rains in the desert where rainfall controls the growth of larval food plants. In March 2019, after heavy rain produced an abundance of vegetation in the deserts, Southern California saw these butterflies migrating by the millions across the state.

 

Similarly, heavier than usual rain during the 2018-2019 winter seems to have been the cause of the extraordinarily large migration observed in Israel at the end of March, estimated at a billion individual butterflies. Painted lady migration patterns are highly erratic and they do not migrate every year. Some evidence suggests that global climatic events, such as el Niño, may affect the migratory behaviour of the painted lady butterflies, causing large-scale migrations. The first noticeable wave of migration in eastern Ukraine was noted in the 20s of April 2019. From May 15, numbers began to grow and it was possible to observe hundreds of this species in the Kharkiv region of Ukraine, including in the city streets of Kharkiv.

 

Based on experimental data, the painted lady's migration pattern in northern Europe apparently does not follow a strict north-west heading. The range of headings suggests that migrating butterflies may adjust their migration patterns in response to local topographical features and weather, such as strong wind patterns. Laboratory-raised autumn-generation painted lady butterflies were able to distinguish a southern orientation for a return migration path. According to the same laboratory-based study, when butterflies were isolated from the sun, they were unable to orient themselves in a specific direction, opposed to those that did have access to the sun. This suggests that V. cardui requires a direct view of the sky, implying the use of a solar compass to orient its migratory direction and maintain a straight flight path.

 

Mating behaviour in relation to migration

V. cardui displays a unique system of continuous mating, throughout all seasons, including the winter. This may be attributed to its migratory patterns, thus significantly affecting its mating behaviour. During European migrations, the butterflies immediately begin to mate and lay eggs upon arrival in the Mediterranean in the spring, starting in late May. In the United States, painted lady butterflies migrating towards the north experience poor mating conditions, and many butterflies have limited breeding capabilities. The "local adult generation" develops during this time, roughly from the middle of May through early June in conjunction with the butterfly progression throughout their flight.

 

During its migratory process, these painted lady butterflies start breeding, and reproduce entirely throughout their migration. Scientists have not been able to find evidence of their overwintering; this may be because they migrate to warmer locations to survive and reproduce. Female painted lady butterflies may suspend their flight temporarily when they are "ready to oviposit"; this allows them the opportunity to continually reproduce throughout their migrations. Because these butterflies are constantly migrating, male butterflies are thought to lack consistent territory. Instead of requiring territory to mate with females and developing evolutionary behaviour to defend this territory, the mating butterflies appear to establish a particular "time and place" in certain locations that they find to be suitable for reproduction. More specifically, they locate certain perches, hilltops, forest-meadow edges, or other landmarks where they will stay until, presumably, a female arrives to mate.

 

Equally important for the reproduction of the painted lady butterflies is the males' exhibition of polygynous mating behaviour, in which they often mate with more than one female. This is important for painted lady butterflies because the benefits may supersede the costs of polygyny since no permanent breeding ground is used. Upon mating, which typically occurs in the afternoon, female painted lady butterflies lay eggs one by one in their desired breeding locations. The variety of eclosion locations ultimately dictates the male painted lady behaviour.

 

Female painted lady butterflies have been observed to have a relatively "high biotic potential", meaning they each produce large numbers of offspring. This perpetual influx of reproduction may be a reason why these painted lady butterflies have propagated so successfully. One interesting aspect that scientists have observed is that these butterflies like to fly towards rain. Further studies have suggested that the large amounts of rainfall may somehow "activate more eggs or induce better larval development". Inhabited locations begin to observe a large influx of new generations of painted lady butterflies in the fall, particularly in September and October. Their reproductive success declines relatively throughout the winter, primarily through November. However, they still continue to reproduce—an aspect of butterfly behaviour that is quite unique. Scientists hypothesize that these extensive migratory patterns help the painted lady butterflies find suitable conditions for breeding, thus offering a possible reason as to why these butterflies mate continuously.

 

Oviposition

Adult butterflies feed on flower nectar and aphid honeydew. Females oviposit on plants with nectar immediately available for the adults even if it leads to high mortality of the larvae. This lack of discrimination indicates they do not take into account volatile chemicals released from potential host plants when searching for oviposition choices.

 

The availability of adult resources dictates a preference for specific areas of flowers. Flowers with more available nectar result in a larger number of eggs deposited on the plants. This reinforces the idea that the painted lady butterfly does not discriminate host plants and chooses mainly on the availability of adult food sources even if it increases the mortality rate of the offspring. The data also suggest that the painted lady butterfly favors quantity of offspring over quality.

 

Vision

Painted lady butterflies have a visual system that resembles that of a honey bee. Adult V. cardui eyes contain ultraviolet, blue, and green opsins. Unlike other butterflies, such as the monarch or red postman butterflies, painted ladies lack red receptors, which means that they are not sensitive to red light. Behavioral studies on the related species, Vanessa atalanta, have demonstrated that V. atalanta cannot distinguish yellow light from orange light or orange light from red light.

 

Roosting behaviour and territory

Groups of two to eight painted lady butterflies have been observed to fly in circles around each other for about one to five seconds before separating, symbolizing courtship. Groups of butterflies usually will not fly more than 4.5 m away from the starting point. To establish and defend their territories, adult males perch in the late afternoon in areas where females are most likely to appear. Once the male spots a female of the same species, he begins pursuit of her. If the foreign butterfly is a male, the original male will give chase, flying vertically for a few feet before returning to his perch.

 

V. cardui establishes territories within areas sheltered by hedgerows. Vanessa cardui tend to inhabit sunny, brightly lit, open environments and are often attracted to open areas of flowers and clovers. Adults spend time in small depressions in the ground on overcast days.

 

Host plants

Larvae feed on Asteraceae species, including Cirsium, Carduus, Centaurea, Arctium, Onopordum, Helianthus, and Artemisia.

 

The painted lady uses over 300 recorded host plants according to the HOSTS database.

 

Defence mechanisms

The main defence mechanisms of painted lady butterflies include flight and camouflage. The caterpillars hide in small silk nests on top of leaves from their main predators that include wasps, spiders, ants, and birds.

 

Human interaction

Vanessa cardui and other painted lady species are bred in schools for educational purposes and used for butterfly releases at hospices, memorial events, and weddings.

field | work

 

a year of mornings: 7/365

Found on:

vizualize.tumblr.com/post/18065146811/a-glossary-of-telev...

 

The body is a flattened ovoid varying in outline with contraction and extension. White specimens have slightly yellowish rhinophores. Extended length 12 mm, Outer Hebrides, Scotland, April 2018. Leg. D. McKay & S.Taylor.

 

Full SPECIES DESCRIPTION BELOW

PDF available at www.researchgate.net/publication/380099040_Adalaria_proxi...

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

Adalaria proxima (Alder & Hancock, 1854)

Synonyms: Doris proxima Alder & Hancock, 1854; Onchidoris proxima (Alder & Hancock, 1854);

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=140629

GLOSSARY below.

 

Body

The body of A. proxima is a flattened ovoid varying in outline with contraction and extension 01Ap flic.kr/p/QoVm29 . It grows up to 17 mm long in Britain & Ireland, and 25 mm is reported further north. The ample mantle covers the whole body. It varies between white 02Ap flic.kr/p/2csiF1W , mainly in northern Britain, or yellowish 03Ap flic.kr/p/QoVjM5 & 04Ap flic.kr/p/2cQQHaw , mainly further south, but the species is absent south of the Bristol Channel. The mantle has many calcareous spicules; some radiate from the bases of tubercles 05Ap flic.kr/p/2csiCGC . Spicules are often not easily seen dorsally; a ventral view may give better sight of them 06Ap flic.kr/p/QoViTS . Near the mantle edge, many spicules are aligned pointing out from the body, but away from the edge they are crossed by others giving a more confused appearance 07Ap flic.kr/p/2bqHSNh . The mantle is covered by elliptical or fusiform tubercles with a rounded apical point and a narrowed base; the greatest circumference is usually about 45% of the height from the base 08Ap flic.kr/p/QoVijL . Tubercle inflation varies greatly; some apparent geographical variations include:

V1: Dull yellowish/orange with slightly swollen, elliptical or fusiform tubercles found mainly in Northern Ireland, Wales and England. 04Ap flic.kr/p/2cQQHaw & 03Ap flic.kr/p/QoVjM5

V2: Bright golden-yellow or orange with moderately swollen tubercles found in the Lille Belt, Denmark and possibly more widely on the Baltic coast of Denmark. 09Ap flic.kr/p/2berxwF & 10Ap flic.kr/p/P4hMP6 .

V3: Pure, translucent white with moderately swollen tubercles in Orkney, Scotland. 11Ap flic.kr/p/QoVeY7 & 12Ap flic.kr/p/2b91xtz .

V4: Pure, translucent white with inflated onion-shape tubercles. Outer Hebrides, Scotland and possibly most of western Scotland. 02Ap flic.kr/p/2csiF1W & 08Ap flic.kr/p/QoVijL .

Newly formed tubercles near the edge of the mantle 13Ap flic.kr/p/2bqHSFJ , or tubercles on small juveniles, are often smaller and thinner. A bundle of calcareous spicules is sometimes faintly visible as a more opaque vertical core which fans out at the top in each tubercle 13Ap flic.kr/p/2bqHSFJ . From above, yellow ovotestes may be visible through the translucent mantle of mature specimens 02Ap flic.kr/p/2csiF1W .

The linear, untapered, often curved backwards rhinophores 14Ap flic.kr/p/QoVifY have about 10 lamellae when the slug is 5 mm long, about 15 when 10 mm 15Ap flic.kr/p/2csiBeY , and about 18 when 15 mm (Thompson & Brown, 1984). The lamellae slope up towards the anterior; the lower ones do not meet on the posterior face of a rhinophore. A small blunt apex protrudes above the lamellae 16Ap flic.kr/p/2csiB4C . The basal part is smooth and swollen. There is no obvious rhinophoral sheath, but the rim of the retraction pit is slightly raised 05Ap flic.kr/p/2csiCGC . The rhinophores are usually slightly darker than the mantle; on pure white specimens they are usually a duller yellowish-white 02Ap flic.kr/p/2csiF1W .

The gills are unipinnate with a thick midrib and crooked, variably-sized pinnae 14Ap flic.kr/p/QoVifY & 17Ap flic.kr/p/2csiAUu . There are about 6 gills when the slug is 5 mm long, about 9 when 10 mm and about 11 when 15 mm (Thompson & Brown, 1984), arranged around the anus in a ring with a posterior gap occupied by a tubercle 18Ap flic.kr/p/2csiAD9 . On white specimens the gills and mantle are translucent white with an opaque white area at the base of the gills. A proxima, like other species in the family Onchidorididae, is a phanerobranch with gills that contract independently of each other and do not retract out of sight into a single common cavity 18Ap flic.kr/p/2csiAD9 .

When fully extended, the head has a large, semicircular oral veil in front of a large oral opening with wrinkled edges 19Ap flic.kr/p/2csiArA . A section of the front edge of the veil is often folded down on right and left. On white specimens the veil is translucent white with pale yellow around the opening.

The foot is rounded at both ends; more broadly and gently at the anterior 06Ap flic.kr/p/QoViTS . It is concealed by the ample mantle and rarely extends beyond the rear of the mantle edge 20Ap flic.kr/p/2csiA27 . On white specimens the sole is translucent white showing through its posterior half the slightly-purplish brown digestive gland 06Ap flic.kr/p/QoViTS .

 

Key identification features

Adalaria proxima

1) Up to 17 mm long in Britain & Ireland, 25 mm reported further north.

2) Ovoid, club-shape tubercles with a rounded apical point and a narrowed basal stem; the greatest circumference is usually about 45% of the height from the base 08Ap flic.kr/p/QoVijL .

3) Tubercles have spicules arranged in a central core, often only indistinctly visible 13Ap flic.kr/p/2bqHSFJ . Mantle spicules radiate from tubercles; not in visible diagonal lines.

4) On large specimens 15 mm long, up to nineteen lamellae on each linear, untapered rhinophore arising from a smooth, swollen, sheathless base 15Ap flic.kr/p/2csiBeY & 16Ap flic.kr/p/2csiB4C . Erect rhinophore often curved backwards 14Ap flic.kr/p/QoVifY .

5) Absent further south than Bristol Channel. NBN records on south coast are probably misidentified Onchidoris muricata.

 

Similar species

Onchidoris muricata (O.F.Müller, 1776) : 21Ap flic.kr/p/2b91znK .

1) Usual maximum length 14 mm.

2) Spheroidal, club-shape tubercles with gently rounded or flattened apex and narrowed base; greatest circumference usually about 66%, or more, of the height from the base16Ap flic.kr/p/2csiB4C & 11Ap

flic.kr/p/QoVeY7 . Body quite firm with many spicules.

3) Tubercles have spicules creating appearance of segments of a peeled orange 12Ap flic.kr/p/2b91xtz .

4) Up to 12 lamellae on each rhinophore 16Ap flic.kr/p/2csiB4C

5) On rocky shores all round Britain, including south coast.

 

Adalaria cf. proxima

22Ap flic.kr/p/2bRRUT3 & 23Ap flic.kr/p/2cXQ164

2) Ovoid, club-shape tubercles with a rounded apical point and a narrowed basal stem; the greatest circumference is usually about 45% of the height from the base.

3) Tubercles have spicules arranged longitudinally. Dorsolateral mantle spicules in diagonal lines.

4) About ten lamellae on each linear, slightly tapered rhinophore arising from a smooth, sheathless base.

5) On Pacific coasts of Canada & north-west U.S.A.

 

Adalaria loveni (Alder & Hancock, 1862)

1) Up to 32 mm long.

2) Widely spaced, very large, wider than tall, lumpy, rounded tubercles with flattened tops interspersed with much smaller tubercles 24Ap flic.kr/p/2b91yMB & 25Ap flic.kr/p/2bqHQpj . Some uncertain specimens have contracted or poorly developed, widely spaced tubercles 26Ap flic.kr/p/2csixFf & 27Ap flic.kr/p/2csiwQY .

3) Tubercles are soft with a central core of spicules.

4) Rhinophore has up to 25 lamellae according to Bergh (1880) in Thompson and Brown (1984), but often fewer 25Ap flic.kr/p/2bqHQpj .

5) On Norwegian coast; possibly absent from Britain & Ireland.

Of A. loveni, Thompson & Brown (1984) wrote, 'This is a distinctive species', and Eliot (1910) stated, 'It can be easily recognised by the huge tubercles' , but there is uncertainty and lack of consensus on the differentiation of British and Irish specimens from A. proxima. The image of an 8 mm long A. loveni in Thompson & Brown (1984) resembles photographs of A. proxima, such as 28Ap flic.kr/p/2csiyZY , much more closely than Alder's image in Eliot (1910) of A. loveni 29Ap flic.kr/p/2csiyDN and photographs of typical A. loveni 24Ap flic.kr/p/2b91yMB . The inflation of tubercles on A. proxima varies considerably, and those with the most inflated ones are liable to be mistaken for A. loveni. Norwegian specimens 25Ap

flic.kr/p/2bqHQpj show that the tubercles are distinctly shaped and, because none like them have been seen/photographed recently in Britain and Ireland, it has been suggested (Picton & Morrow accessed August 2018) that A. loveni may not occur there now. Alder and Hancock, who first named the species (1862), wrote, “A single specimen of this species was found by the Rev. A.M. Norman among stones between tide-marks, on the south side of Bantry Bay, in the autumn of 1858. It is remarkable for the enormous size of its tubercles, which, though soft and having a puffed appearance, contain each a bundle of spicula.” It is unknown whether their illustration 29Ap flic.kr/p/2csiyDN is of the Bantry specimen or a Norwegian one sent to them. It is possible that it was at Bantry in 1858 when the climate was cooler than in the 20th and 21st Centuries. The tubercles on some specimens from Norway are large and widely spaced, as on A. loveni, but in shape resemble, more or less, those on A. proxima 26Ap flic.kr/p/2csixFf & 27Ap flic.kr/p/2csiwQY .

A study (Hallas & Gosliner, 2015), which was not focused on differentiating this pair of species, showed strong similarities in DNA and morphology (J. Hallas, 2018, pers. comm. 31 October) between specimens identified as A. proxima from Maine, U.S.A. and A. loveni from Norway. It is possible that A. loveni is one of the many distinct geographical forms of A. proxima or part of a cline in A. proxima.

 

Habits and ecology

In Britain, A proxima lives on the lower levels of rocky shores and sublittorally to about 60 m. It feeds preferentially on Electra pilosa which often grows on Fucus serratus and Laminaria as well as other algae and substrates. If E. pilosa is not available, it will feed on other encrusting bryozoans such as Flustrellidra hispida, Membranipora membranacea and Alcyonidium polyoum .

It is a simultaneous hermaphrodite and breeds in Britain from February to May. The spawn is a ribbon attached to algae by one edge in a spiral of one to three turns 30Ap flic.kr/p/2csizBu . The ova, up to 2500, are white or cream, and hatch in 5 to 6 weeks at 10ºC into large well developed lecithotrophic larvae which spend a brief time in the plankton, when they may feed but this is not essential for complete metamorphosis into adult form in as little as 24 hours from hatching (Thompson & Brown, 1984). Senescence and death follow shortly after spawning so specimens are rarely seen in summer months while they are ova, larvae or small unobtrusive juveniles. The short time spent in the plankton restricts dispersal and genetic interchange and may favour the development of local variants. This may partly explain differences in colour forms and inflation of tubercles as shown in images 02Ap flic.kr/p/2csiF1W 03Ap flic.kr/p/QoVjM5 and 11Ap flic.kr/p/QoVeY7 .

 

Distribution and status

A proxima has been recorded from Greenland to Massachusetts, and from Iceland and Norway to Wales, south-east Scotland and Demark. GBIF map www.gbif.org/species/2292099 has records (preserved material) from Alaska to British Columbia, but DNA confirmation that it is this species is desirable 22Ap flic.kr/p/2bRRUT3 & 23Ap flic.kr/p/2cXQ164 . It is common in the north of Britain and Ireland but there are no confirmed reports to the south of the Bristol Channel (Thompson & Brown, 1984). NBN UK map species.nbnatlas.org/species/NBNSYS0000173608 shows records in Yorkshire from the early Twentieth Century when temperatures were lower and the now absent northern Testudinalia testudinalis was also in the area. It was common in Anglesey, North Wales in the 1950s (Thompson & Brown, 1984) but apparently scarce in recent warmer years, though there was a record substantiated with image in December 2018 31Ap flic.kr/p/2pJti8R . NBN has improbable records unsupported by images by JNCC off south-east England in 2005 and off Plymouth in 1999. Thompson & Brown (1984) wrote, “Mis-identifications may have led to records from the Plymouth area and the Channel Islands”.

Acknowledgements

This account was made possible by the generous help of others. David McKay and Simon Taylor collected and brought specimens to me for photography and study. Jørn Ari and Bernard Picton provided Danish images, and Nils Aukun and Erling Svensen granted use of their Norwegian images so that the uncertain relationship with A. loveni could be examined. Joshua Hallas, Manuel Malaquias and Bernard Picton provided helpful information. I am most grateful to them all. Any error or omission is my responsibility.

 

Links and references

 

Alder J. & Hancock A. 1854. Notice of some new species of British Nudibranchiata. Annals and Magazine of Natural History. ser. 2, 14: 102 - 105. biodiversitylibrary.org/page/18659561

 

Alder, J. & Hancock, A. 1845 - 1855. A monograph of the British nudibranchiate mollusca. London, Ray Society.

www.biodiversitylibrary.org/item/131598#page/122/mode/1up &

www.biodiversitylibrary.org/item/131598#page/125/mode/1up

 

Alder, J. & Hancock, A. 1862. Descriptions of a new genus and some new species of naked Mollusca. Annals and Magazine of Natural History. ser. 3: 10:261 - 265., [description of A. loveni] biodiversitylibrary.org/page/22162433

 

BioImages – virtual field guide (UK) www.bioimages.org.uk/index.htm

[prey species].

 

Catteneo Vietti, R., Angelini, S., Gaggero, L. & Lucchetti, G. 1995. Mineral composition of nudibranch spicules. J. Mollus. Stud. 61 (3): 331-337. Abstract at mollus.oxfordjournals.org/content/61/3/331.abstract

 

Eliot, C.N.E. 1910. A monograph of the British nudibranchiate mollusca. Ray Society, London. Supplementary volume.

[Description of A. loveni] archive.org/stream/british_nudibranchiate_mollusca_pt8_lo...

[Plate showing A. loveni]

archive.org/stream/british_nudibranchiate_mollusca_pt8_lo...

 

Hallas, J.M. & Gosliner, T.M. 2015. Family matters: The first molecular phylogeny of the Onchidorididae Gray, 1827 (Mollusca, Gastropoda, Nudibranchia) Molecular Phylogenetics and Evolution 88 (2015) 16 - 27.

Abstract at www.sciencedirect.com/journal/molecular-phylogenetics-and...

 

Picton, B.E. & Morrow, C.C. Adalaria loveni (Alder & Hancock, 1862) in

Encyclopedia of marine life of Britain and Ireland (Accessed August 2018)

www.habitas.org.uk/marinelife/species.asp?item=W13230

 

Picton, B.E. & Morrow, C.C. Encyclopedia of marine life of Britain and Ireland. [For prey]. www.habitas.org.uk/marinelife/index.html

 

Telnes, K. The marine flora and fauna of Norway. [For prey] Accessed August 2018. www.seawater.no/fauna/bryozoa/pilosa.html

 

Thompson, T.E. & Brown, G.H. 1984. Biology of opisthobranch molluscs 2. London, Ray Society.

 

Todd, C.D, 1979. Reproductive energetics of two species of dorid nudibranchs with planktotrophic and lecithotrophic larval strategies. Marine Biology 53 (1): 57- 68 pdf of preview from link.springer.com/article/10.1007/BF00386529

 

Glossary

cryptobranchiate = (of dorid seaslugs) able to retract gills into a single capacious gill cavity.

fusiform = slender, spindle-shaped, tapering almost equally towards both ends.

 

lamellae = (sing. lamella) small plates on rhinophores, or leaflets of gill.

mantle = (of nudibranchs) sheet of tissue forming part or all of notum (dorsal body surface).

 

lecithotrophic = of larva that derives sufficient nutrition from the yolk of its egg to metamorphose to adult form without feeding.

 

phanerobranchiate = (of dorid seaslugs) contracting gills separately; not all retracting into a single gill cavity (see cryptobranchiate).

 

pinna = (pl. pinnae) primary element/leaflet of a pinnate gill, leaf, feather etc.

plankton = animals and plants that drift in pelagic zone (main body of water).

rhinophores = chemo-receptor tentacles on top of head of nudibranch.

 

spicule = (in dorid seaslugs) small, slender, sharp-pointed feature mainly composed of calcite (CaCO3) and brucite (Mg(OH)2) .

 

spiculate = containing spicules.

unipinnate = (of gill plume) branching singly; boughs but no subsequent branches or twigs, in one plane like a feather.

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

  

Top left: Height 4mm, 57% of breadth. Body whorl 86% of height. Aperture 64% of height.

Bottom left: Height 6.6mm, 57% of breadth. Body whorl 85% of height. Aperture 60% of height. Adapical angle about a right angle.

Right: Height 13mm, 83% of breadth; highest h/b % in collection of 71 shells from S. to N. coasts of Britain. Body whorl 71% of height. Aperture 52% of height.

 

FULL Species DESCRIPTION below.

Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/.

PDF available at www.researchgate.net/publication/349290429_Steromphala_um...

 

Steromphala umbilicalis (da Costa, 1778)

 

Account (2014) revised 2019, 2020 & 2022. Currently accepted name, Steromphala umbilicalis (da Costa, 1778) is used in revised parts. Unrevised text may retain old name, Gibbula umbilicalis.

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=141801 (The image of a Spanish shell on this web page is very unlike British G. umbilicalis.)

Synonyms: Trochus umbilicalis Da Costa, 1778; Trochus umbilicatus Montagu, 1803 in Jeffreys, and Forbes & Hanley; Gibbula umbilicalis (da Costa, 1778) until recently.

Vernacular: Flat top shell, Purple top shell, Top môr porffor (Welsh), Genavelde tolhoren (Dutch), Troque ombliqué gibbule (French).

 

*GLOSSARY below.

 

Description

Note, this description applies to specimens from Britain. Further south there are more similar species, and the features found on S. umbilicalis specimens may differ from those in Britain.

Shell

Breadth to 22mm, height to 16mm. Conoidal; height frequently about 60% of breadth 1Gu flic.kr/p/g3jtCF, but varies about 45% to 85% 2Gu flic.kr/p/g3iVPG . Sutures distinct. Spire small, body whorl about 80% of height 2Gu flic.kr/p/g3iVPG . Small blunt apex, often eroded exposing silver nacre layer, and sometimes exposing upper end of hollow columella 29Gu flic.kr/p/g3hpai . Up to 11 raised spiral lines on body whorl below angulated periphery i.e. on base of shell 4Gu flic.kr/p/g3iV21 . Large round white-bordered umbilicus always present 4Gu flic.kr/p/g3iV21 . Aperture approximately semi-circular, about 60% of height 2Gu flic.kr/p/g3iVPG ; parietal lip reflected as a glaze onto body whorl 4Gu flic.kr/p/g3iV21 ; white columellar lip adjoining umbilicus; adapical angle about a right angle 2Gu flic.kr/p/g3iVPG . Interior of shell thickened by shiny silvery white layers of aragonite crystals (nacre), apart from border just within outer lip coloured as exterior of shell 4Gu flic.kr/p/g3iV21 .

Ground colour of shell whitish, often partly greenish or stained brownish by environmental factors 5Gu flic.kr/p/g3iQgZ ,opaque, almost lustreless. Broad, slightly wavy, transverse, red to purple bands radiate from apex across the whorls when viewed dorsally, increasing in number on each subsequent whorl. Width of gaps between bands changes little as shell grows 5Gu flic.kr/p/g3iQgZ . Protoconch (first two turns of spire) cream and unbanded 3Gu flic.kr/p/2gGDVh4 but often stained or eroded on older shells. Beach-worn shells with nacre layer exposed by erosion share with other top shells the vernacular name “Silver tommy” flic.kr/p/d3BfZw ( image by Cat Walden) . Circular spiral operculum with many narrow coils , transparent horn colour, on withdrawn animal shows pale opercular disc and blackish flesh 6Gu flic.kr/p/2gGDV8r .

Body

Ground colour of flesh yellowish or greenish, often heavily marked black-purple on adults, but early juveniles lack dark pigment 7Gu flic.kr/p/2gGDUFj Snout short, yellowish or greenish with dense transverse dark purple lines 9Su flic.kr/p/g3iPdM , except pinkish ventral surface 8Gu flic.kr/p/g3jpPt . Dorsum of snout has pair of yellow, white and grey crenate cephalic lobes; transverse when snout contracted 9Gu flic.kr/p/g3iPdM , longitudinal when snout extended 10Gu flic.kr/p/g3iT4d . Dorsal and lateral rim of snout tip is circular and crenate 8Gu flic.kr/p/g3jpPt . Mouth a vertical slit, with diagonal extensions at each end demarcating dorsal, ventral and lateral lips 11Gu flic.kr/p/g3iRGy . Ventral lip has median line 12Gu flic.kr/p/g3iT1N (with a short projection reported by Fretter & Graham, but not visible in this set of images). Radula appears as soon as mouth starts to open 12Gu flic.kr/p/g3iT1N , and long marginal teeth fan out widely 13Gu flic.kr/p/g3iRByas they and odontophore with erect, scraping lateral teeth press onto substrate to brush up food particles. Marginal teeth curl back to pull particles into mouth as radula retracts 10Gu flic.kr/p/g3iT4d . Cephalic tentacles long, densely setose 14Gu flic.kr/p/g3iRv1 , whitish, tinted pale purple basally, with encircling black-purple rings 9Gu flic.kr/p/g3iPdM . Eye on stout yellowish or greenish peduncle at base of each cephalic tentacle 14Gu flic.kr/p/g3iRv1 ; small black “pupil” exposed, surrounded by grey ring of rest of eye showing through translucent peduncle 12Gu flic.kr/p/g3iT1N . Sensory tentacle at base of right eye peduncle 15Gu flic.kr/p/g3iNsZ (none on left). Large neck-lobe (lappet) behind each eye; translucent white and yellow (sometimes greenish) with fine dark purple freckling in parts; left one strongly fringed 16Gu flic.kr/p/g3iNsD ; right one, sub-rectangular with smooth edges, guides voided faeces away from mantle cavity containing ctenidium 17Gu flic.kr/p/g3iSBG , curled at edge 15Gu flic.kr/p/g3iNsZ or curved to form exhalent respiratory siphon 18Gu flic.kr/p/g3iSG1 . Dorsal surface of foot densely covered in tubercles arranged in rows parallel to perimeter 19Gu flic.kr/p/g3iRHh , ground colour yellowish mostly covered with dense brown or dark purple except peripherally. Well developed epipodium, greyish dorsally and yellowish or greenish ventrally, runs along each side of foot 20Gu flic.kr/p/g3iMUz ; bears three white, transversely lined with dark purple, setose epipodial tentacles arising from white jagged sheath bearing a tubercle 21Gu flic.kr/p/g3jnPX ; Opercular disc not expanded into lobe enclosing any of operculum edge 21Gu flic.kr/p/g3jnPX , visible as pale patch through transparent operculum when animal retracted into shell 7Gu flic.kr/p/g3iSzW . Sole tawny white, short, approximately oval, divided longitudinally by slight furrow 22Gu flic.kr/p/g3iQym , finely fringed periphery 19Gu flic.kr/p/g3iRHh . Fertilization external, so no penis on males. Sometimes the comb-like ctenidium can be seen in the mantle cavity behind the head, and the pink internal buccal mass is visible inside the pigmentless body of juveniles 7Gu flic.kr/p/2gGDUFj .

 

Key identification features

The principal source of misidentification by both novice and experienced workers is that young small shells of S. cineraria, with low profile and relatively widely spaced bands, are mistaken for S. umbilicalis.

In a sample of 71 shells of S. umbilicalis and S. cineraria, collected from sites between north coast Scotland and south coast England, the average number of bands within each width category on S. cineraria was approximately double the average onS. umbilicalis, with no overlap in the ranges. Bands were counted around the periphery of the body whorl, including part of the outer lip to complete the circuit. Examples:

Width 14 mm to 15.9mm

S. umbilicalis mean 22 bands (range 18 –31 bands).

S. cineraria mean 52 bands (range 35 –68 bands).

Width 12mm to 12.9mm 25Gu flic.kr/p/g3iQef

S. umbilicalis mean 17 bands (range 13 –23 bands).

S. cineraria mean 41 bands (range 34 –49 bands).

Width 5mm to 8.9mm 26Gu flic.kr/p/g3iMZU

S. umbilicalis mean 10 bands (range 7 –13 bands).

S. cineraria mean 25 bands (range 19 –29 bands).

 

Steromphala umbilicalis

1. Shell has broad red to reddish-purple bands radiating from apex across the whorls 5Gu flic.kr/p/g3iQgZ . Maximum shell width 22mm.

2. Number of bands within each width category is approximately half the average found on S. cineraria, with no overlap in the ranges. 25Gu flic.kr/p/g3iQef , 26Gu flic.kr/p/g3iMZU and data above.

3. Bands on S. umbilicalis are wider than those on G. cineraria.

4. Shell always has a large round umbilicus 4Gu flic.kr/p/g3iV21 .

5. Shell profile usually low, but variable 2Gu flic.kr/p/g3iVPG

6. In Britain, adults found littorally, but not living sublittorally, from Kent along south and up west coasts round to Loch Eriboll 28Gu flic.kr/p/g3iMp5 on north coast Scotland, with a few records on west coast of Orkney (recent move eastwards in the islands). NBN records in North Sea, especially divers’ records, are probably misidentifications of S. cineraria. It is advisable to keep live-taken specimens or clear photographs with scale/measurement (not estimate) to support any claimed S. umbilicalis record from this area; it may move into N. Sea with warmer winters.

Similar species

Steromphala cineraria

1. Narrow, greyish bands (bluish-purple-grey, brown-grey or dark brown-grey, but not reddish-purple) on yellowish or light grey ground colour radiate from apex of shell across the whorls. 31Gu flic.kr/p/2gGozaw Maximum shell width 16mm.

2. Number of bands within each width category on S. cineraria is approximately double the average on S. umbilicalis, with no overlap in the ranges 25Gu flic.kr/p/g3iQef , 26Gu flic.kr/p/g3iMZU and data above.

3. Bands on S. cineraria are narrower than those on S. umbilicalis . But beware; bands on both species increase only slightly in width with shell growth, so they look proportionately wider on very small shells, leading sometimes to small S. cineraria being mistaken for S. umbilicalis because of “wide” bands 26Gu flic.kr/p/g3iMZU .

4. Umbilicus progressively narrows with age 31Gu flic.kr/p/2gGozaw . Adult shell may have very restricted or completely closed umbilicus, but juveniles may have large round umbilicus like that of S. umbilicalis 27Gu flic.kr/p/g3iMVW

5. Shell profile higher than S. umbilicalis on average, but large overlap; only use profile to distinguish S. cineraria if shell like straw bee-hive (skep) with height over 86% of breadth 32Gu flic.kr/p/2gGnTY9 .

6. Adults found littorally and sublittorally all round UK, including North Sea.

 

Phorcus lineatus (da Costa, 1778) [=Osilinus lineatus, Monodonta lineata].

1. Many short zig-zag streaks of brown, red, purple or green transversely across whorls, arranged into clear bands radiating from apex only on early whorls 33Gu flic.kr/p/2gGoyvW Beware small shells under 15mm width dominated by early whorls; in apical view can resemble S. umbilicalis of similar size 29Gu flic.kr/p/g3hpai .

Maximum width 25mm, height 30mm.

4. Umbilicus open on juveniles up to 5mm high, larger shells usually have umbilicus covered by inner lip of aperture folded over it, leaving an umbilical depression and occasionally a minute hole. Rounded tooth on columella.

5. Shells up to about 16mm height have moderately low profile; larger ones can be very tall.

6. Adults live near high water mark in SW Britain from Isle of Wight to Anglesey, and around most of Ireland except part of east coast.

 

Steromphala tumida (Montagu, 1803) 34Gu flic.kr/p/2gHazwt

1. Brownish bands and/or spots. Maximum shell width 10mm.

4. Comma shaped umbilicus narrows and closes with age.

5. Sharply pointed cone with stepped profile and flat body whorl..

6. Most British coasts, usually sublittoral, rarely live on shore, but dead shells sometimes on strandline. Iceland to Spain.

 

Steromphala pennanti (Philippi,1851) 35Gu flic.kr/p/2gHaz75

1. Shell colour and banding very similar to S. umbilicalis, but bands tend to break into chequers on base and sometimes on rest of shell.

4. Small constricted umbilicus on juveniles, closed on full grown adults.

6. Littoral and sublittoral, Channel Islands and Cherbourg to Spain; not British mainland.

 

Habits and ecology

On brown fucoid seaweeds or under stones, even if devoid of fucoids, on rocky shores MHWN to MLWS. Not often sublittoral; distribution controlled by winter air temperature (not below about 4.4°C Feb. mean) and/or surface water temperature (not below about 6°C Feb mean). Also in rock pools, extending above MHWN. Cilia on fringed left neck-lobe wave to create inhalent current to ctenidium within mantle cavity 16Gu flic.kr/p/g3iNsD . Cilia on smooth edged right neck-lobe create exhalent current for respiratory water 18Gu flic.kr/p/g3iSG1 , ova or sperm 30Gu flic.kr/p/g9YWaN , and excreta 17Gu flic.kr/p/g3iSBG . Locomotion is enabled by direct, ditaxic waves on the sole of the foot 23Gu flic.kr/p/g3jnav ; turning is caused by different rates of wave flow on either side of the central furrow, or even reversal of direction to retrograde on one side. Feeds on brushings from seaweeds and on algal debris. Faecal string from stomach has U shape cross-section; thinner cylindrical string from kidney is deposited along the groove of U and is seen in excreted string 24Gu flic.kr/p/g3iQ1u . Spawning triggered by rise in temperature; dates vary within period May-September at different locations. External fertilization occurs as non-buoyant yellowish-green ova released singly via right neck-lobe from mantle cavity 30Gu flic.kr/p/g9YWaN . Ova hatch as trochophore larvae, which quickly metamorphose into veliger larvae that semi swim/crawl on or near bottom. As little or no planktonic phase, distant transport will be a rare occurrence, and remote establishment of reproducing population unlikely as external fertilization requires dense population for success.

 

Distribution and status

Gibraltar to west coast of Orkney, (Not North Sea, N.E. Irish Sea or Baltic, all too cold; many erroneous records on GBIF and NBN) GBIF map www.gbif.org/species/9471950 . U.K. map NBN species.nbnatlas.org/species/NHMSYS0021185570

IMPORTANT! Many records marked on the NBN map for North Sea are 'ABSENCE records', without proof otherwise, other N. Sea records should be regarded as misidentifications . S. umbilicalis is used as a text book example of temperature control of distribution (Lewis, J. R., 1964). It is important that the distribution is not confused by inaccurate identification, and that any range extension because of climate warming is reliably documented.

Edit, June 2022: with recent increases in sea temperature there has been a range expansion into the south of the North Sea which has reached north of the Thames Estuary (2022, S. Taylor, pers. comm.).

Acknowledgements

I thank Peter Topley for helpful I.T. advice, and I am grateful to David Fenwick www.aphotomarine.com/index.html for use of two of his images for the Similar Species section.

 

Links and references

 

Crothers, J.H. 2001. Common topshells: an introduction to the biology of Osilinus lineatus with notes on other species in the genus. Field studies, 10, 115-160.

(Free pdf at fsj.field-studies-council.org/media/342011/vol10.1_265.pdf )

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1849), London, van Voorst. (As Trochus umbilicatus; Free pdf at archive.org/details/historyofbritish02forb/page/518 Use slide at base of page to select pp.519-522.) (Error on plate DD, vol. 1, of G. cineraria, acknowledged in text, shows both neck lobes fringed; right one should have smooth edge.)

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London. (Error in description states “Animal like G. cineraria but cephalic lappets and left neck lobe have smooth edges.” : both species have fringed edges on cephalic lappets (lobes) and left-neck lobe, and smooth edges on the right neck-lobe.)

 

Jeffreys, J.G. 1862-69. British conchology. vol. 3 (1865). London, van Voorst. (As Trochus umbilicatus; Free pdf at archive.org/details/britishconcholog03jeffr . Use slide at base of page to select pp.312- 315.)

 

Lewis, J.R. 1964. The ecology of rocky shores. London, Hodder & Stoughton.

 

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=141801 (The image of a Spanish shell on this web page is very unlike British G. umbilicalis.)

 

Glossary

adapical – towards the apex of the shell.

aperture – mouth of gastropod shell; outlet for head and foot.

bifid – divided into two parts by a cleft.

cephalic – (adj.) of or on the head.

cilia – (pl.) vibrating linear extensions of membrane used in feeding or locomotion. (“cilium” singular).

ciliated – (adj.) coated with cilia.

 

columella - solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.

 

columellar – (adj.) of or near central axis of spiral gastropod.

columellar lip - lower (abapical) part of inner lip of aperture.

 

conoidal – nearly conical

diatom – microscopic aquatic alga with siliceous cell-walls.

 

conchiolin – horny flexible protein that forms the operculum of most marine gastropods, and a matrix for the deposition of calcium carbonate to create a mollusc’s shell.

 

ctenidium – comb-like molluscan gill; usually an axis with a row of filaments either side.

 

ditaxic – (of locomotion waves on foot) double series of waves, out of phase with each other, one series on each side of central furrow on sole.

 

direct - (of locomotion waves on foot) waves travel from posterior to anterior.

 

ELWS – extreme low water spring tide (usually near March and September equinoxes).

 

epipodial - (adj.) of the epipodium (collar or circlet running round sides of foot of some gastropods).

 

epipodium - collar or circlet running round sides of foot of some gastropods, often bearing epipodial tentacles.

 

everted – turned inside out.

height – (of gastropod shells) distance from apex of spire to base of aperture.

 

mantle – sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

 

odontophore – cartilaginous “tongue” that supports and protracts /retracts the radula.

opercular – (adj.) of the operculum.

opercular groove – groove across foot which produces conchiolin for creation of operculum to its posterior. Conchiolin produced faster at right end of groove so resultant ribbon curves to form spiral operculum.

 

opercular disc – part of foot that growing operculum rotates on.

opercular lobe – extension of opercular disc round edge of part of operculum.

operculum – plate of horny conchiolin, rarely calcareous, used to close shell aperture.

periostracum – thin horny layer of chitinous material often coating shells.

parietal lip – upper part of inner side of gastropod aperture.

plankton – animals and plants that drift in pelagic zone (main body of water).

retrograde - (of locomotion waves on foot) waves travel from anterior to posterior.

 

setose – bearing many setae.

seta – stiff hair or bristle. (pl. setae)

suture – groove or line where whorls of gastropod shell adjoin.

 

trochophore – spherical or pear-shaped larvae that swim with aid of girdle of cilia. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for limpets, Trochidae and Tricolia pullus.

 

umbilicus – cavity up axis of some gastropods, open as a hole or chink on base of shell, often sealed over.

 

veliger – shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

Length 32 mm. LWS. Isle of Lewis, Scotland. April 2018. Leg. D.W. McKay & S.Taylor.

In the N.E. Atlantic, T. marmorea grows to a maximum of 45 mm long and 27mm wide.

To the naked eye, the girdle and valves appear smooth, apart from near-rectangular, distinct, growth lines on the valves.

 

SPECIES DESCRIPTION part A: BELOW

SPECIES DESCRIPTION part B: flic.kr/p/2gzajx3

Key id. features: flic.kr/p/2gzaj8q

Sets of OTHER SPECIES:

www.flickr.com/photos/56388191@N08/collections/

Revised, 2020, PDF version at www.researchgate.net/profile/Ian_Smith19/research

 

Tonicella marmorea (O.Fabricius, 1780)

Images: 1 to 54 T. marmorea; 55 to 59 vacant; 60 to 72 similar species.

Authors: Paula Lightfoot, Simon Taylor and Ian F. Smith.

 

Meaning of scientific name:

marmorea (Latin) = resembling marble

 

Synonyms: Chiton marmoreus O.Fabricius, 1780; Chiton ruber (non Linnaeus, 1767) Spengler, 1797; Chiton laevigatus Fleming, 1813; Chiton latus Lowe, 1825;

Vernacular: Mottled red chiton; Marbled mail-shell; Lleuen fraith y graig (Welsh); Chiton rouge marbré (French); Marmorierte Käferschnecke (German); Marmorleddsnegl (Norwegian); Marmoreret skallus (Danish);

 

GLOSSARY BELOW This account adheres to the standardised terminology for chitons proposed by Schwabe (2010). Some of Jones & Baxter (1987) alternatives are indicated in the glossary as (a.k.a.).

 

Shell Description

Low form in N.E. Atlantic up to 45 mm long and 27mm wide 1Tm flic.kr/p/2gz9Ndp . High form in N.W. Atlantic up to 37 mm long and 20mm wide (Kaas & Belle, 1985). In dorsal view, outline elliptical, larger specimens generally more strongly curved than smaller ones; width about 60% of length. Narrow girdle (total of two sides) occupies between 12% and 35% of animal width, specimens over 20mm length generally having the proportionally wider girdles (Baxter & Jones, 1986).

Eight overlapping valves 2Tm flic.kr/p/2gzajx3 have an upper coloured layer, ‘tegmentum’, of aragonite, and a lower layer, ‘articulamentum’, of white 3Tm flic.kr/p/2gzaj8q or, sometimes on jugal tract, pink 4Tm flic.kr/p/2gzaiL8 or yellow 5Tm flic.kr/p/2gzaipX aragonite. There are also an uppermost layer, ‘properiostracum’, and a discontinuous lowermost layer, ‘myostracum’, that are so thin and transparent as to be unnoticeable.

Dorsal surface (tegmentum) of valves appears smooth to naked eye apart from near-rectangular, distinct, growth lines 1Tm flic.kr/p/2gz9Ndp & 6Tm flic.kr/p/2gzaifJ . Colour variable; dirty white, cream, various shades of brown 7Tm flic.kr/p/2gz9KP1 , red 8Tm flic.kr/p/2gz9Khz , and ochre arranged in blotches or intricate zig-zag lines 9Tm flic.kr/p/2gzahiD . Rarely entirely marmorated. Frequently, but not always, approximately triangular patches on the jugal areas have lighter colours 8Tm flic.kr/p/2gz9Khz . Valves ii, iv and, less consistently, vii often have more dark colour than the other valves 8Tm flic.kr/p/2gz9Khz , 9Tm flic.kr/p/2gzahiD ,10Tm flic.kr/p/2gz9Jnt , 11Tm flic.kr/p/2gzagd2 . Colour partly derives from pigment in properiostracum; brightest on live specimens in good condition and fades rapidly on specimens that are in poor condition or dead 12Tm flic.kr/p/2gzafNQ .

The head valve (i) is almost semicircular 13Tm flic.kr/p/2gz9HfJ , with a shallow V posterior edge when viewed in situ on living specimen 7Tm flic.kr/p/2gz9KP1 . The tegmentum on intermediate valves (ii –vii) has slightly rounded end margins, and nearly straight and parallel anterior and posterior margins 4Tm flic.kr/p/2gzaiL8 , except the anterior of valve ii which projects more at its centre. Valves ii to vii have a keeled jugum 14Tm flic.kr/p/2gzaf1c with small posterior beak 15Tm flic.kr/p/2gzaeRK . Beaks are often eroded away 8Tm flic.kr/p/2gz9Khz .They vary in elevation (H/W% of valve iv) from 20% to 37% or more in NE Atlantic 17Tm and usually higher in NW Atlantic c. 44% (Kaas & Belle, 1985). The side slopes of valves ii to vii are straight 16Tm flic.kr/p/2gz9Gyy or slightly convex, or a combination of straight and convex when viewed from the anterior or posterior 17Tm flic.kr/p/2gzaeBw . Their lateral areas are very slightly raised and separated from the central area by a shallow, unobtrusive, diagonal depression 18Tm flic.kr/p/2gzaeov & 20Tm flic.kr/p/2gzadZ4 .

The tail valve (viii) is small and about twice as wide as its antero-posterior length. The unobtrusive, antemedian mucro is encircled by the concentric growth lines 13Tm flic.kr/p/2gz9HfJ & 21Tm flic.kr/p/2gz9FQz . The steep postmucronal slope is straight in lateral profile 6Tm flic.kr/p/2gzaifJ . The colour of the antemucronal area resembles that of the jugal area of intermediate valves 13Tm flic.kr/p/2gz9HfJ .

Canals permeate the tegmentum 22Tm flic.kr/p/2gzadNh & 23Tm flic.kr/p/2gzadLi and terminate on its dorsal surface as a minute stipple of caps (surface seems smooth to naked eye, at least 3X magnification and cleaned valve needed) 18Tm flic.kr/p/2gzaeov on caps arranged in an offset grid pattern 24Tm flic.kr/p/2gz9FCA . Some canals penetrate the articulamentum to form holes on its ventral surface, especially in the slit rays and jugal tract 23Tm flic.kr/p/2gzadLi & 25Tm flic.kr/p/2gz9Foc , 26Tm flic.kr/p/2gz9Fkw .

Insertion plates on ends of valves ii – vii embedded in the girdle are separated by a single slit 5Tm flic.kr/p/2gzaipX & 23Tm flic.kr/p/2gzadLi ; head valve (i) has 7 to 13 slits 25Tm flic.kr/p/2gz9Foc and tail valve (viii) has 5 to 11 slits 27Tm flic.kr/p/2gz9FcF . On the ventral articulatum a diagonal slit ray runs from each slit to the posterior edge of valves i – vii 25Tm flic.kr/p/2gz9Foc & 26Tm flic.kr/p/2gz9Fkw and from the slits to the mucro position where they meet the open canal ends in the jugum on valve viii 27Tm flic.kr/p/2gz9FcF .

The articulatum on valves ii – viii 3Tm flic.kr/p/2gzaj8q projects forwards as a pair of curved, wide, short (front to rear) apophyses separated by a narrow, straight, jugal sinus (gap) that is less than 25% length of an apophysis 28Tm flic.kr/p/2gzad9b . The apophyses on valve ii are more angular and those on valve viii are smaller and more angular 4Tm flic.kr/p/2gzaiL8 . Apophyses extend under the next valve forwards 2Tm flic.kr/p/2gzajx3 and leave a scar of similar shape on it when the connecting muscle is removed 29Tm flic.kr/p/2gzad5Z . The head valve (i) is the only one that lacks apophyses as there is no valve to its anterior to be attached to 25Tm flic.kr/p/2gz9Foc . [It is difficult to cut away the muscle without breaking the apophyses on freshly dead chitons. They can be disarticulated without damage to the valves by standing them in shallow 10% NaOH overnight. CAUTION; extremely caustic, burns skin and seriously damages eyes. Or, keep in preservative for some time until the muscle weakens and then pull the valves out with strong forceps]

 

Body Description

Head and foot only fractionally protrude into view naturally on live animal 30Tm flic.kr/p/2gzacGE & and can usually only be seen when breeding 31Tm flic.kr/p/2gz9EjD or if the animal is dislodged from the substrate or adhering to glass. When attached to a smooth surface, the extended head is anteriorly convex to fit the curve of the shell, and posteriorly concave fitting round the anterior of the foot and extending laterally as mouth lappets 32Tm flic.kr/p/2gzabYW . The shape varies when the head is retracted or unattached to the substrate 33Tm flic.kr/p/2gzabUC . The head lacks eyes and tentacles; its main feature is a large transverse slit-mouth with wrinkled lips. When preserved, the mouth may gape widely and its fleshy surround may distort to form a hood 32Tm flic.kr/p/2gzabYW . As on chitons generally, the radula is a chitinous ribbon bearing teeth in rows of seventeen 34Tm flic.kr/p/2gz9DMm . In each row, the central (rhachidian) tooth is a reflexed, rectangular channel with a widened chisel-like terminal blade 36Tm flic.kr/p/2gzabrZ [The image and text in Jones & Baxter (1987) differs from this description of the rhachidian tooth which is based on SEM images in this account]. Next to it, the minor (first) lateral tooth is small and bladeless. The major (second) lateral tooth has a long shaft and a large tridentate head ( one small, sharp denticle and two wide, rounded denticles) 35Tm flic.kr/p/2gzabKK . The first and second uncinal teeth are small and unobtrusive between the bases of the major lateral and major (third) uncinal tooth which has a long shaft with head shaped and sculptured like a feather 37 Tm . At the margin of the radula in each row there are three low plates (marginal ‘teeth’). The teeth are colourless when their formation commences at the rear of the translucent radula sac. They darken and harden through rust-red and brown as they move along the sac acquiring magnetite (iron oxide), and the principal cutting teeth are black by the time they emerge from the anterior of the sac 34Tm flic.kr/p/2gz9DMm . Magnetite is the hardest material made by any living organism (Botelho, 2013).

Aesthetes (sensory tissue) fill canals permeating the tegmentum 22Tm flic.kr/p/2gzadNh & 37Tm flic.kr/p/2gz9CVr . They terminate on fine stipple (at least X3 magnification needed) 18Tm flic.kr/p/2gzaeov as sensory organs on the dorsal surface of valves 19Tm flic.kr/p/2gzaed5 , 21Tm flic.kr/p/2gz9FQz , 24Tm flic.kr/p/2gz9FCA .

Canals vertically penetrate the articulamentum in the slit rays and jugal tract as conduits for branches of the body’s lateral nerve cord 22Tm flic.kr/p/2gzadNh . Immediately below the valves, the mantle is tough, thin, translucent epidermis, but it is greatly thickened where reflected around the periphery of the shell to form a fleshy girdle 6Tm flic.kr/p/2gzaifJ into which the articulamentum insertion plates at the ends of the valves are deeply embedded 14Tm flic.kr/p/2gzaf1c & 38Tm flic.kr/p/2gzaaV8 . The girdle has cream or yellowish-white flesh with a tough transparent yellowish cuticle that survives when flesh is removed with NaOH 39Tm flic.kr/p/2gzaaSC . The cuticle on the ventral surface of the girdle (hyponotum) and dorsal surface (perinotum) appears leathery-smooth to the naked eye 6Tm flic.kr/p/2gzaifJ , but strong magnification shows a covering of very small spicules 40Tm flic.kr/p/2gz9CKB & 41Tm flic.kr/p/2gz9CEG . Scanning electron microscope images 42Tm flic.kr/p/2gzaaGT show that the spicules on the (dorsal) perinotum are small, c. 27µ long, widely spaced cones with sharp apices, and that spicules on the hyponotum are longer, c. 35µ , more closely packed ovoids with longitudinal ribs. . The hyponotum is whitish, but usually extensively stained yellowish to brownish by firm contact with the substrate 43Tm flic.kr/p/2gzaakv . The perinotum is yellowish with, usually, a brown or purplish band at each end of valves ii to vii, and several bands associated with valves i and viii 7Tm flic.kr/p/2gz9KP1 . The bands usually have several yellowish blotches on them. Frequently, part or all of the perinotum is suffused with verdigris-green which partially obscures the band pattern 40Tm flic.kr/p/2gz9CKB . The foregoing colours are usual in Britain but Kaas and Belle (1985) state that the girdle is “of an even brownish colour, exceptionally with alternating zones of light and dark brown”. This may be the case in America, though 9 images from Quebec all have banded girdles (DORIS, 2019), and dried or preserved specimens often lose the pattern 12Tm flic.kr/p/2gzafNQ & 38Tm flic.kr/p/2gzaaV8 . The edge of the girdle has a marginal fringe of straight, obtusely pointed, c. 48µ long, spicules that are very difficult to discern with the naked eye 42Tm flic.kr/p/2gzaaGT , 43Tm flic.kr/p/2gzaakv & 45Tm flic.kr/p/2gz9BP8 . The girdle can be flexed upwardly outwards at the anterior 30Tm flic.kr/p/2gzacGE to admit inhalent water to the peripheral mantle cavity, and at the posterior to form a channel for the release of exhalent water, faecal pellets and ova or sperm 31Tm flic.kr/p/2gz9EjD .

An open narrow mantle cavity runs around whole animal; contains 15 to 26 small ctenidia on each side (Baxter & Jones, 1986), often on larger specimens for nearly the whole length of the foot (merobranch, but nearly holobranch, arrangement) 46Tm flic.kr/p/2gza9Xr & 47Tm flic.kr/p/2gza9KN . Number of ctenidia increases with age. Between the mantle cavity and hyponotum the mantle fold is unobtrusive, except where it widens near the posterior into a mantle lappet 30Tm flic.kr/p/2gzacGE and may partly conceal the ctenidia. Anus opens at end of an anal papilla into the mantle-cavity at posterior by a channel to the exterior formed by deflection/ depression of girdle 48Tm flic.kr/p/2gza9pc . The dorso-ventrally flattened pericardium containing the heart is located above the anal papilla, and is sometimes partly visible on live specimens 48Tm flic.kr/p/2gza9pc . Nephridiopores and gonopores open laterally into posterior quarter of cavity. No penis as external fertilization. Foot yellow to orange, elongate ovate, anterior wider than posterior, curvature of ends varies, sometimes truncate 49Tm flic.kr/p/2gza9mG , no medial dividing line. When foot spreads widely, it and the mantle fold/lappet close and conceal much of the pallial cavity 44Tm flic.kr/p/2gzaaj3 . The foot has many strong transverse muscles 50Tm flic.kr/p/2gza92J and the body has a strong lateral longitudinal muscle 38Tm flic.kr/p/2gzaaV8 & 50Tm flic.kr/p/2gza92J that encircles the entire body passing under the outer margins of the valves. The valves have four sets of muscles.:

a) A pair of lateral muscles connect the foot to each end of the valves, one on each side of the slit 38Tm flic.kr/p/2gzaaV8 & 50Tm flic.kr/p/2gza92J , leaving an opaque scar when removed 3Tm flic.kr/p/2gzaj8q .

b) A pair of straight muscles 51Tm flic.kr/p/2gz9AHL pass along the jugum, attaching to the anterior margin of the jugal sinus of each valve and to the body wall under the previous valve.

c) On each side of a valve an oblique muscle 51Tm flic.kr/p/2gz9AHL attaches to the jugal sinus close to the straight muscle and travels anteriorly outwards under the diagonal line that separates the lateral area of the tegmentum from its central area. The anterior end of the muscle attaches to the body wall under the preceding valve on which it leaves a comma shaped scar 3Tm flic.kr/p/2gzaj8q .

d) The transverse muscle 51Tm flic.kr/p/2gz9AHL consists of dorso-ventral fibres connecting the apophyses of one valve to the underside of the preceding valve where it leaves curved scars matching the outlines of the apophyses. The muscle colour is often the same as that of the jugal tract; white, yellow 51Tm flic.kr/p/2gz9AHL or pink 52Tm flic.kr/p/2gza8R8 .

 

Glossary

μm = 0.001 mm, 1000μm = 1 mm

acicular = slender and tapering to a point; needle-like.

aesthetes = complex of canals and cavities filled with sensory tissue that permeate tegmentum and locally penetrate articulamentum. Open as sensory pores on dorsal surface of valves; probably compensate for lack of sensory structures on head. Some sense light; other sensory function(s) uncertain, but various authors have variously proposed chemoreception, mechanoreception, properiostracum replenishment and secretion of protective substances.

 

a.k.a. = also known as.

antemedian = (syn. antemedial) situated to anterior of middle.

antemucronal area = area situated to anterior of mucro.

apophysis = (pl. apophyses) anterior extension of articulamentum which underlies preceding valve; on all valves except head valve (i).

 

aragonite = orthorhombic crystalline mineral-form of calcium carbonate www.minerals.net/mineral/aragonite.aspx . Less common on land than calcite, but, currently, the more frequent mineral-form in oceans and living mollusc shells.

 

articulamentum = inner shell-layer of chiton valves, usually hard, white, porcelaneous aragonite and often differently coloured in central part.

 

calcite = trigonal crystalline mineral-form of calcium carbonate www.minerals.net/mineral/calcite.aspx . More common on land than aragonite, but, currently, the less frequent mineral-form in oceans and living mollusc shells. More resistant than aragonite to acid rain corrosion; forms outer shell layer of shore-dwelling Littorina species in cool climates. (Corrosion of calcium carbonate faster at cold temperatures).

 

cephalic = (adj.) of or on the head.

chemoreception = sensing of chemicals; “smell / taste”.

chitin = semitransparent flexible horny protein. Does not occur in molluscs.

chitinous = (adj.) resembling chitin.

cilia (pl.) = motile linear extensions of membrane used in locomotion, or to create water currents in feeding. (“cilium” singular).

 

coll. = in the collection of (named person or institution) (cf. legit).

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

 

dioecious = having separate male and female individuals.

dorso-ventrally flattened = as if pressed flat from above.

ELWS = extreme low water spring tide (usually near equinoxes).

epithelium = tissue forming outer layer of body surface, “skin”.

 

girdle = (on chiton) peripheral band of thickened, reflexed mantle that encloses ends of valves.

 

gonopore = genital opening through which eggs or sperm are released.

holobranch = (of chitons) ctenidia in mantle cavity extend full length of foot.

hyponotum = ventral cuticle of chiton’s girdle.

insertion plate = (on most chitons) extension of articulamentum which inserts into mantle on lateral margin of intermediate valves, anterior margin of head valve and posterior margin of tail valve. Inserts into, and anchors valve to, the girdle muscle block.

 

intermediate valve = (of chiton) any valve (ii – vii), except head valve (i) and tail valve (viii).

 

jugal area = summit zone of chiton valves on dorsal surface.

jugal tract = summit zone of chiton valves on ventral surface.

jugum = summit of chiton valves.

lateral area = (on intermediate valve of chiton) triangular area with its base along lateral edge of valve and its apex near the centre of the posterior edge. a.k.a. lateral triangle.

 

legit = (abbreviation; leg. or lgt.) collected/ found by (cf. coll.)

LWS = low water spring tide, two periods of a few days each month when tide falls lowest.

 

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

mantle cavity = (on chitons) a.k.a. pallial groove; narrow groove around whole foot and head, roofed by mantle and containing ctenidia, nephridiopores and gonopores.

 

magnetite = mineral of iron oxide, hardest material made by any living organism.

marmorated = veined or streaked like marble.

mechanoreception = sensing of touch, sound, pressure change and/or posture.

 

MLW = mean low water mark.

 

merobranch = (of chitons) gills in pallial cavity only in posterior two-thirds of animal.

 

mucro = projection on tail valve (viii) of chiton demarking posterior from rest of valve. Varies in prominence and position.

 

myostracum = thin, inconspicuous, discontinuous, innermost layer of chiton shell.

 

nephridium = tubular glandular excretory/ osmoregulatory organ. a.k.a. kidney.

 

nephridiopore = opening of nephridium for excretion. a.k.a. renal pore.

odontophore = firm, approximately ellipsoid, structure of cartilage supporting radula. Protruded like a tongue to operate radula.

 

pericardium = membranous sac containing heart and start of aorta.

perinotum = dorsal cuticle of chiton’s girdle.

pleural area = (on intermediate valve of chiton) triangular area with its base along anterior edge of valve and its apex near the centre of the posterior edge. a.k.a. median triangle.

 

postmucronal = situated to posterior of mucro.

properiostracum = (on chitons) outermost layer of colour-bearing proteinaceous material, sometimes resembling collagen in texture and differing in composition from periostracum of most other mollusc groups.

 

plankton = animals and plants that drift in pelagic zone (main body of water).

radula = chitinous ribbon of teeth extruded on a tongue-like structure (odontophore) to rasp food.

 

side slope = (on chiton) shape in profile view (from posterior or anterior) of lateral areas of intermediate valves; may be straight, convex, concave or a combination of these.

 

sinus = 1. dilated channel or receptacle containing blood etc. 2. (re. chiton valves) curved bay or gap.

slit ray = row of canal pores running diagonally from lateral slit to posterior edge on ventral surface of chiton valve. a.k.a. notch ray.

 

suture = (of chiton) line where two valves meet.

tegmentum = outer shell-layer of chiton valves, usually porous and relatively soft. (Covered by transparent properiostracum when live.)

 

trochophore = spherical or pear-shaped larvae that swim with aid of girdle of cilia. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for limpets, Trochidae, Tricolia pullus and (with no veligers) chitons.

 

uncinate = having a hooked shape.

uncinate blades = largest two teeth in each row of seventeen on chiton radulae; principal scraping blades. Often darkened more than other teeth by high magnetite content.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

  

SPECIES DESCRIPTION continues in part B under image 2Tm at : flic.kr/p/2gzajx3 .

  

Through Language in Vienna

 

A collaboration between Parrhesia, Zochrot and Ursula Hofbauer

 

Within the framework of the exhibition: OVERLAPPING VOICES

Israeli and Palestinian Artists

Essl Museum, Vienna

16/05 – 26/10/08

Opening: 15/05/08, 7.30 p.m.

Curators: Karin Schneider and Friedemann Derschmidt (Rites-institute), Vienna

Co-Curators: Tal Adler, Amal Murkus, Israel

 

Through Language is a public art project, a visual dictionary and site-specific glossary alternating between Arabic, German and Hebrew.

Giving the Arabic and the Hebrew languages presence in the public sphere in Europe evoke issues relating to the presence of our cultures within Europe, in the past as well as in the present .

We hope to question the tendencies of the Western world to perceive Arabic and Hebrew languages and cultures as threats and thus refer to the constant uprising of xenophobia and Anti-Semitism in Europe.

he project also proposes language and culture as an arena for listening and engaging in dialogue with the others.

 

AugartenStadt was not chosen by chance; as "verlorene Insel (lost island)" was the main scene of Jewish displacement in 1938 – and as a site of new migration, it is the space of current conflicts between populism, xenophobia and Muslim self-assertion.

 

The project was carried out before in two places in Israel – in Jerusalem and in Jaffa – employing Arabic and Hebrew transcriptions and translations. The project was a response to the widespread practice of Israeli extremists erasing the Arabic language from street signs, by using stickers or spray paint and to the state practices of Palestinian cultural oppression by marginalizing and under-privileging Arabic - an official language in Israel.

The Arabic words constitute keys to stories, memories, hopes and fears that are for the most part heard only inside private homes, without a presence in the public sphere and its discourse. The idea was to allow Arabic a presence in our public life.

We would like to manifest the presence of the Palestinian citizens of Israel - the native people upon whose destruction our state is built - through the visualization of their language and to express our wish to become culturally integrated in the Middle East.

 

Through Language was first presented in August 2006 in the exhibition "Neighborhood Works" (Curated by the Sala-Manca group) in the German Colony neighborhood of Jerusalem. The project's second presentation was in Jaffa where it was curated by the "Ayam" artist group, with the support of the Tel Aviv–Jaffa Municipality's Culture & Arts Division, Department of Arts; The Israeli Center for Digital Art, Holon; and The New Israel Fund.

 

Parrhesia is a group of educators, social activists and artists from the fields of graphic and industrial design, cinema, photography, video and fine art, who are engaged in Israel's civil society.

The group collaborates with organizations for social change and community activists – in addition to their independent activities in the public sphere.

 

Zochrot ["Remembering"] is a group of Israeli citizens working to raise awareness of the Nakba, the Palestinian catastrophe of 1948. Zochrot endeavors to make the history of the Nakba accessible to the Israeli public, so as to engage Jews and Palestinians in an open recounting of their painful common history.

Zochrot hopes that by bringing the Nakba into Hebrew, the language spoken by the Jewish majority in Israel, they can make a qualitative change in the political discourse of this region. Acknowledging the past is the first step in taking responsibility for its consequences.

This must include equal rights for all the peoples of this land, including the right of Palestinians to return to their homes.

 

Parrhesia and Zochrot are engaged in an ongoing process of collaboration – the publication of Sedek, a magazine about the ongoing Nakba. Its first two issues can be viewed in the following links:

www.parrhesia.org/sedek.pdf

parrhesia.org/sedek2.pdf

  

DI Ursula Hofbauer is a Vienna-based artist and architect who has been working in and with public space in several exhibitions and art projects, including: “Strange Views” (1999), an exhibition project in the Viennese Prater with lettering on sidewalks; “Permanent Breakfast” (1999-2005), the everlasting breakfast in public space; wine-tasting with homeless people under a Viennese Bridge (2002); and art projects with refugees (2004-2006). Lectures, publications and guided tours about the Permanent Breakfast project, gender and public space and Viennese landmarks. Hofbauer is decidedly dedicated to all questions of democratic use and appropriation of public space and resulting designs.

We thank Aktionsradius Wien at Gaussplatz www.aktionsradius.at/

for a lot of valuable information, their hospitality and straightforward support.

 

Glossary printed on the inside front cover of a Bond Clothes, Philadelphia, Pa. notepad (see below) that dates to the 1930s.

 

--------

 

Swing Stuff

 

Alligator--swing fan

Beat my socks--broke

Beat up--no coin

Blip--very good

Blowing his top--hot licks

Bunny--coat

Cat--swing addict

Corny--old-fashioned

Copasetic--everything's okay

Crawl into the nest--get some sleep

Dicty--high class

Diggit out--go to town, deliver

Early black--evening

Fews and twos--money, cash

Freeby--no charge, gratis

Gutbucket--low-down music

Hep cat--wise guy

Hipchick--snooty gal

Hot licks--improvised stuff

Icky--one who is not hep

Jam--swing session

Jelly--on the house

Jitterbug--swing fan

Jive--to kid along

Joint is jumping--place is lively

Killer-diller--thrill

Muggin'--making 'em laugh

Nix out--to eliminate

Riff--hot lick, high notes

Rug-cutter--good dancer

Schmaltz--sentimental

Sharpies--dancers who thrive on swing

Slide your jib--talk freely

Takeoff--play a solo

Tin ears--one who dislikes swing

Togged to the bricks--dressed up

Whipped up--exhausted

Woof-hound--alligator high on swing

Thick white labial varix (1) near thin growth (2) at the palatal (outer) lip.

North Wales, March 2015.

Full SPECIES DESCRIPTION BELOW

PDF available at www.researchgate.net/publication/368472122_Rissoa_lilacin...

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Rissoa lilacina Récluz, 1843

 

Synonyms: Rissoa punctata Potiez & Michaud, 1838; Rissoa rufilabrum Alder, 1844; Rissoa porifera Lovén, 1846; Rissoa violacea var. ecostata Jeffreys, 1867;

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=141358

Meaning of name: Rissoa = named for G.A. Risso (1777 to 1845).

lilacina = (Latin) lilac (colour of parts of shell).

 

GLOSSARY below.

 

Shell description

R. lilacina grows up to 5 mm high and 2.75 mm wide. The spire forms an almost straight sided cone with apical angle c. 50° fig. 01 flic.kr/p/2ognFB2 , except for forms with more tumid whorls and deeper sutures which disrupt the outline and were segregated in Graham (1988) as R. porifera and R. rufilabrum. The body whorl occupies about 65% to 70% of the shell height fig. 01 flic.kr/p/2ognFB2 .

The sculpture varies. Costal ribs can be absent or strongly developed on the largest three whorls of adults fig. 02 flic.kr/p/2ogoMxx . Ribs are more common in the south of Britain including North Wales. In Scotland un-ribbed shells may predominate. Ribs usually cease on the final part of the body whorl so few are visible on its abapertural face but are prominent above the periphery of the apertural face fig. 02 flic.kr/p/2ogoMxx . Except for the ribs, the surface of the shell has about 20 spiral rows of pits aligned to form a rectangular matrix, often made distinct by brown periostracum in the pits surviving the abrasion from the more raised parts.

When fully grown a white labial varix near the outer (palatal) lip fig. 03 flic.kr/p/2ogofx8 , and sometimes a constricting thickening inside the outer lip, develop, but these features may be missing as the peristome is often extensively broken away fig. 04 flic.kr/p/2ogoqTJ .

The protoconch consists of an embryonic whorl and a distinct larval whorl. The whorls lack obvious sculpture and are more tumid than teleoconch whorls fig. 05 flic.kr/p/2ogoqNy . The protoconch retains a constant size at all growth stages, so appears relatively larger on small, young shells fig. 02 flic.kr/p/2ogoMxx . If the teleoconch retains much of its brown periostracum, the white protoconch contrasts distinctly with it fig. 06 flic.kr/p/2ognFjP . The ground colour of the shell is whitish and slightly translucent showing indistinctly the dark animal within fig. 04 flic.kr/p/2ogoqTJ . Brown areas and the brown periostracum darken the general appearance of some fig. 06 flic.kr/p/2ognFjP , but many are lighter because much of the periostracum is eroded, surviving only in the recessed pits and spaces between the costal ribs fig. 01 flic.kr/p/2ognFB2 . The rim of the aperture and sometimes the areas adjacent to it, both in and outside the aperture, are usually stained lilac fig. 02 flic.kr/p/2ogoMxx . The labial varix sometimes has red marks fig. 06 flic.kr/p/2ognFjP . Dry, vacant, beached shells have usually lost much of their colour fig. 07 flic.kr/p/2ognFeD .

The aperture height is 35 to 50% of the shell height; its long axis is tilted 30° from the axis of the spire fig. 01 flic.kr/p/2ognFB2 . It has an oval outline that is narrowest adapically and is angled where the short, near-vertical columellar lip joins the parietal lip fig. 02 flic.kr/p/2ogoMxx . When not broken, there is a slight spout at the base of the aperture fig. 01 flic.kr/p/2ognFB2 . There is no open umbilicus but the columellar lip is everted over an umbilical groove. The parietal lip is well formed and, with the columellar lip and thin out-turned palatal lip, forms a distinct continuous peristome when not broken away.

Body description

The flesh is white with brown or black pigment covering the dorsal surface of the snout and extending as a band from below the eye onto and along the foot and onto the widely projecting opercular lobe fig. 08 flic.kr/p/2ognEH8 & fig. 23 flic.kr/p/2ogoq4C . The tip of the snout is deeply bifid and bright yellow fig. 09 flic.kr/p/2ogiyUa & fig. 10 flic.kr/p/2ogoTjn . The contents of the proximal 80% of the slender, tapering, transparent cephalic tentacles are bright canary yellow fig. 10 flic.kr/p/2ogoTjn . The swollen base of each tentacle is coloured brown fig. 14 flic.kr/p/2ogopTn or black except for an unpigmented section containing a large black eye with an opaque white streak to the posterior of the eye fig. 11 flic.kr/p/2ogmdf2 & fig. 12 flic.kr/p/2ogiyMg . The body behind the tentacles is white except for a faint yellowish brown patch between and immediately behind the tentacles fig. 12 flic.kr/p/2ogiyMg & fig. 13 flic.kr/p/2ogmdaC .

When fully extended, the foot is widest and truncated at the anterior and tapers to a rounded posterior point fig. 14 flic.kr/p/2ogopTn . Its bilaminate, anterior edge fig. 15 flic.kr/p/2ogmd6u contains the outlet for mucus from the large, opaque white, triangular, anterior pedal mucous gland fig. 16 flic.kr/p/2ogmd5x . The gland is edged on the dorsal surface of the foot with a thin greyish or brownish line along each side. There is a strong groove across the foot and constriction at 25% of its length from the anterior fig. 14 flic.kr/p/2ogopTn & fig. 23 flic.kr/p/2ogoq4C . There is a, sometimes faint, brown or black mark down the flanks of the foot along the posterior of the groove fig. 17 flic.kr/p/2ognErw . The posterior half of the sole has an opening to the posterior pedal gland fig. 14 flic.kr/p/2ogopTn .

The operculum is transparent tinted brownish fig. 14 flic.kr/p/2ogopTn & fig. 18 flic.kr/p/2ognEk4 and often difficult to discern fig. 14 flic.kr/p/2ogopTn . It rests on a brown or black opercular disc which protrudes laterally as prominent opercular lobes fig. 19 flic.kr/p/2ognEg1 . Part of the disc is yellow where it consists of the end of a yellow columellar muscle attached to the operculum fig. 08 flic.kr/p/2ognEH8 & fig. 13 flic.kr/p/2ogmdaC . A long metapodial tentacle which is proximally yellow and distally translucent whitish fig. 20 flic.kr/p/2ogmcUN & fig. 21 flic.kr/p/2ogopAD extends from the yellow part of the opercular disc to or beyond the posterior tip of the foot when in motion.

The mantle is translucent white fig. 22 flic.kr/p/2ogiyjN showing the colours of the shell interior through it fig. 23 flic.kr/p/2ogoq4C with a short, translucent pallial tentacle protruding beyond the shell fig. 24 flic.kr/p/2ogopvy from the adapical angle of the aperture fig. 21 flic.kr/p/2ogopAD . Within the mantle cavity a substantial white ctenidium stretches from left to right under the roof and males have a penis attached to the body behind the cephalic tentacles fig. 18 flic.kr/p/2ognEk4 .

 

Key identification features

Rissoa lilacina

1) Maximum height 5 mm.

2) Costal ribs can be absent or strongly developed on the largest three whorls of adults fig. 06 flic.kr/p/2ognFjP .

3) White labial varix, when fully grown, may have a few red brown marks, but not a brown falciform mark (comma) across it fig. 06 flic.kr/p/2ognFjP .

4) Aperture rim and sometimes adjacent areas inside and outside the aperture are usually stained lilac.

5) Protoconch has two tumid, white whorls, occasionally tinted lilac fig. 05 flic.kr/p/2ogoqNy . Teleoconch whorls only slightly tumid.

6) Translucent white cephalic tentacles have a thick, medial, bright canary yellow line within them fig. 17 flic.kr/p/2ognErw .

7) Brown or black pigment covers dorsal surface of snout and extends as a band onto and along foot and to widely projecting opercular lobe fig. 17 flic.kr/p/2ognErw .

8) Brown or black mark down the flanks of the foot, often faint and does not spread far onto sole fig. 17 flic.kr/p/2ognErw .

9) Mediterranean to Norway, excluding inner Baltic and much of the North Sea.

 

Similar species

Rissoa parva (da Costa, 1778) fig. 25 flic.kr/p/2ogoL3P

1) Maximum height 5 mm.

2) Costal ribs can be absent or strongly developed.

3) When fully grown, usually has a white labial varix with a brown falciform mark across it.

4) Aperture rim not usually stained lilac.

5) Protoconch has 3 or 4 white whorls when unworn, occasionally tinted lilac. Teleoconch whorls vary from slightly tumid to distinctly tumid.

6) Translucent white cephalic tentacles have a thin, sometimes discontinuous, medial, opaque white line within them.

7) Snout translucent whitish; sometimes has narrow blackish mark and/or a few opaque white marks.

8) Broad transverse dark band on foot spreads onto periphery of sole.

9) Northern Norway to Canary Islands, Mediterranean and Black Sea. Not inner Baltic.

 

Rissoa guerinii Récluz, 1843 fig. 26 flic.kr/p/2ognE23

1) Maximum height 6 mm.

2) Costal ribs well developed.

3) When fully grown, has a thick, white labial varix.

4) Aperture rim not usually stained lilac. Patch of lilac-brown often in throat of aperture.

5) Protoconch has two tumid, often whitish-grey whorls. Teleoconch whorls distinctly tumid, except two uppermost.

6) Translucent white cephalic tentacles have within them a sometimes fragmentary, opaque, yellow line.

7&8) Snout and sides of foot brown (Graham, 1988)

9) Canary Islands and Mediterranean northwards to Bretagne and south-west England.

 

Habits and ecology

R. lilacina lives at LWST and sublittorally to 20 m at salinities above 21‰ (Warén, 1996). It is found on some Zostera beds and on algae, such as Treptacantha nodicaulis (Withering) Orellana & Sansón, attached to stones on sandy substrate in sheltered sites such as coastal lagoons fig. 27 flic.kr/p/2ogmcdc . It feeds on diatoms, organic detritus and fragments of algae swept with its radula from the surface of the Zostera or algae. Frequent damage to the lip and body whorl of the shell in sheltered conditions is probably the result of attack by crabs fig. 04 flic.kr/p/2ogoqTJ .

Locomotion: The anterior pedal mucous gland fig. 16 flic.kr/p/2ogmd5x discharges within the bilaminate anterior edge of sole fig. 15 flic.kr/p/2ogmd6u , which spreads the mucus to lubricate creeping. The posterior pedal gland fig. 14 flic.kr/p/2ogopTn secretes mucus which hardens on contact with sea water to form strong threads to anchor the snail and act as climbing lines in its movement around algae. Turning and folding fig. 16 flic.kr/p/2ogmd5x are assisted by the transverse crease across the foot fig. 14 flic.kr/p/2ogopTn . R. lilacina feeds by grazing algal fragments, detritus and microphytes with its radula from the surface of algae. It produces orange-brown, oval faecal pellets fig. 22 flic.kr/p/2ogiyjN .Little is known of its reproduction. Males are smaller than females and have a penis for internal fertilization. Captive spawning starts at 8 to 9°C and increases at 10 to 11°C (Warén, 1996). The egg capsules are shaped as a hemispherical lens with a narrow marginal brim (Fretter & Graham, 1978), diameter 1.3 to 1.5 mm containing 60 to 80 ova (Warén, 1996). They are probably attached to alga and/or the shells of other individuals. No data are available on larval development but the different embryonic and larval whorls of the protoconch fig. 05 flic.kr/p/2ogoqNy suggest that there is a free living planktonic veliger stage similar to that of other rissoids.

 

Distribution and status

Rissoa lilacina occurs from Lofoten, Norway to the Mediterranean but is absent from the inner Baltic and most of the North Sea. It was especially abundant on Zostera in the Kattegat before destruction of the plant by disease in the 1930s (Warén, 1996). It is locally abundant in suitable habitats but occurs at far fewer sites in Britain than Rissoa parva and Pusillina inconspicua, which are usually found with it. GBIF map www.gbif.org/species/8205460 . It is found at suitable sites in Ireland, except on some of its Irish Sea coast, and in Britain except the coasts of the North Sea and north-east Irish Sea, U.K. map NBN species.nbnatlas.org/species/NHMSYS0021055540

 

Acknowledgements

I gratefully thank Paul Brazier and Florence and Marc Cochu for use of images.

 

Links and references

Alder, J. 1844. Descriptions of some new British species of Rissoa and Odostomia. Ann. Mag. nat. Hist. 13 (series 1): 323-328 & plate viii preceding p. 323 . (as Rissoa rufilabrum.) archive.org/details/annalsmagazineof13lond/page/325/mode/1up

 

Cochu, F. & Cochu, M. Rissoa guerinii, Nature 22, Estran 22, faune et flore de la zone de balancement des marées en Côtes d'Armor. (accessed February 2023). nature22.com/estran22/mollusques/gasteropodes/gasteropode...

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853), London, van Voorst. (as R. rufilabrum) p. 106 & plate xxvii archive.org/details/historyofbritish03forbe/page/106/mode...

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

Fretter, V. and Graham, A. 1978. The prosobranch molluscs of Britain and Denmark. Part 4– Marine Rissoacea. J. Moll. Stud. Suppl. 6, 153-241.

 

Graham, A. 1988. Molluscs: prosobranch and pyramidellid gastropods. Synopses of the British Fauna (New Series) no.2 (Second edition). Leiden, E.J. Brill/Dr. W. Backhuys. 662 pages.

 

Høisaeter, T. 2009. Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna Norvegica 28: 5-106 www.researchgate.net/publication/41758474_Distribution_of...

 

Jeffreys, J.G. 1862-69. British conchology. vol. 4 (1867). London, van Voorst. archive.org/details/britishconcholog04jeffr/page/32/mode/... . p.33. (as R. violacea)

 

Rasmussen, E. 1973. Systematics and ecology of the Isefjord marine fauna (Denmark). Ophelia, 11, 1-495.

 

Warén, A. 1996. Ecology and systematics of the north European species of Rissoa and Pusillina (Prosobranchia: Rissoidae). J. mar. biol. Ass. U.K. 76, 1013-1059.

 

Wigham, G.D. & Graham, A. 2018. Marine gastropods 3: Neogastropoda. Synopses of the British Fauna (New Series) no.62. (206 pages). Field Studies Council,Telford, England.

  

Glossary

adapical = towards the apex of the shell.

aperture = mouth of gastropod shell; outlet for head and foot.

bifid = divided into two parts by a cleft.

bilaminate = (adj.) formed of two layers.

cephalic = (adj.) of or on the head.

coll. = in the collection of (named person or institution, compare with legit).

columella = solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.

 

columellar = (adj.) of or near central axis of spiral gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

costa = strong rib running across a whorl of a gastropod shell at right angles to direction of coiling and any spiral striae.

 

costae = (pl.) strong axial ribs running across a whorl of a gastropod shell at approximately right-angles to direction of coiling and any spiral striae.

 

costal = (adj.) of, or arranged like, costae.

costate = bearing costae.

diatom = microscopic aquatic alga with siliceous cell-walls.

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

ELWS = extreme low water spring tide (usually near March and September equinoxes).

embryonic whorl = tiny, initial, apical whorl of gastropod; formed while embryo in ovum. It plus larval whorls comprise the protoconch. [Some sources confusingly call whole protoconch the embryonic whorls.]

 

falciform = shaped like a sickle blade.

height = (of gastropod shells) distance from apex of spire to base of aperture.

labial varix = especially strong or broad costa (rib) along edge of outer lip of aperture. Sometimes other varices mark positions of previous prolonged pauses in growth.

 

larval whorls = whorls near apex of gastropod shell formed while a planktonic veliger larva. They plus initial apical embryonic whorl comprise the protoconch.

 

legit = (abbreviation; leg.) collected/ found by (compare with coll.)

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

 

LWST = low water spring tide, two periods of a few days each month when tide lowest.

metapodium = hind part of the foot.

metapodial = of the metapodium.

mucus = (noun) viscous, slippery substance secreted by various glands on molluscs.

mucous = (adj.) pertaining to mucus.

opercular = (adj.) of the operculum.

opercular disc = part of foot that growing operculum rotates on.

opercular lobe = extension of opercular disc beyond edge of operculum.

operculum = plate of horny conchiolin, rarely calcareous, used to close shell aperture.

palatal lip = outer lip of gastropod aperture.

peristome = entire rim of aperture.

plankton = animals and plants that drift in pelagic zone (main body of water).

protoconch = apical whorls produced during embryonic and larval stages of gastropod; often different in form from other whorls (teleoconch).

 

stria = (pl. striae) very narrow spiral groove.

suture = groove or line where whorls of gastropod shell adjoin.

teleoconch = part of shell other than the apical protoconch.

umbilicus = cavity up axis of some gastropods, open as a hole or chink on base of shell, often sealed over.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

Length 29 mm when live. LWS. Isle of Lewis, Scotland. April 2018. Leg. D.M. McKay & S.Taylor.

Girdle and body removed except the transverse muscles which connect the valves.

As with chitons generally, T. marmorea has eight overlapping valves; i = head valve, viii = tail valve.

Left: The upper layer, ‘tegmentum’, is made of coloured aragonite.

Right: The lower layer, ‘articulamentum’, is made of white aragonite, sometimes with a pink jugal tract (1). The anterior of the articulamentum on valves ii to viii has curved extensions called apophyses (2). They underlie the next valve forwards and are connected to it by the transverse muscle. The valves in the image are articulated as in life because the transverse muscles have been left intact except that connecting valves ii and iii.

 

SPECIES DESCRIPTION part A: flic.kr/p/2gz9Ndp

SPECIES DESCRIPTION part B: BELOW

Key id. features: flic.kr/p/2gzaj8q

Sets of OTHER SPECIES:

www.flickr.com/photos/56388191@N08/collections/

Revised, 2020, PDF version at www.researchgate.net/profile/Ian_Smith19/research

 

SPECIES DESCRIPTION part B

GLOSSARY BELOW

Key identification features

There is interspecific overlap of many features. The most reliable are valve and girdle surface sculpturing.

Tonicella marmorea O. Fabricius, 1780.

Following is for NE Atlantic. Those in NW Atlantic may differ.

1. Big species. Max. length in NE Atlantic 45mm.

2. Colour variable; dirty white, cream, various shades of brown, red, and ochre arranged in blotches or intricate zig-zag lines. Valves ii, iv and vii often have more dark colour than the other valves 9Tm flic.kr/p/2gzahiD .

3. Girdle is yellowish with a brown or purplish band at each end of valves ii to vii, and several bands by valves I and viii. Usually several yellowish blotches on bands 7Tm flic.kr/p/2gz9KP1 . Frequently, part or all suffused with verdigris-green 40Tm flic.kr/p/2gz9CKB .

4. Apart from growth lines, dorsal surface of valves appears smooth to naked eye 6Tm flic.kr/p/2gzaifJ , but at over X3 (hand lens) magnification, numerous distinct small granules visible 18Tm flic.kr/p/2gzaeov . (Granules may not be discernible in underwater images or on specimens before deposits and properiostracum removed.)

5. Dorsal surface of girdle (perinotum) has widely spaced minute granules (c.27μm long) 40Tm flic.kr/p/2gz9CKB . Usually escape notice in photographs; require strong magnification.

6. At LWS and sublittorally. Not found south of North Wales or Northumberland. (Many dubious records on mapping schemes as easily confused with T. rubra.)

7. 17 – 26 ctenidia along most of each side of foot, arrangement merobranch but nearly holobranch 46Tm flic.kr/p/2gza9Xr .

8. White apophyses on intermediate valves are short (anterior-posterior), wide and gently curved 28Tm flic.kr/p/2gzad9b . Narrow jugal sinus (gap between them) is about quarter width of one apophysis.

 

Similar species

 

Boreochiton ruber (Linnaeus, 1767) (Formerly T. rubra)

1. Medium species. Max. length 15mm.

2. Dorsal surface of valves pink to brick red with patches and streaks of cream and light brown 60Tm flic.kr/p/2gz9xMq .

3. Girdle usually has reddish/pinkish bands alternating with pale bands. Pale bands, often fragmentary, usually thinner than reddish/pinkish bands, and roughly in line with shell-sutures 60Tm flic.kr/p/2gz9xMq .

4. Apart from growth lines, dorsal surface of valves appears smooth to naked eye, but at X30 magnification (dissecting microscope). faint stippling is visible 61Tm flic.kr/p/2gza7Tg .

5. Dorsal surface of girdle (perinotum) has densely-packed, elongate (50 - 60μm), club-shaped granules with packed touching heads giving a mealy appearance. 62Tm flic.kr/p/2gza7G4 .

6. At LWS and sublittorally. All around Britain except NE Irish Sea and southern North Sea where hard substrate is scarce.

7. About 12 ctenidia each side (range 10-15), arrangement merobranch.

8. White apophyses on intermediate valves are prominent and rounded, often almost semicircular 61Tm flic.kr/p/2gza7Tg . Wide jugal sinus (gap between them) is about same width as one apophysis.

 

Lepidochitona cinerea (Linnaeus, 1767).

1. Medium species. Max. length 28mm.

2. Has diverse colour forms, some similar to that of other species 63Tm flic.kr/p/2gza7Dt .

3. Girdle usually has alternating brown (various shades) and whitish, transverse, lozenge-like bands of approximately equal size. Dark bands usually have narrow waist, and light bands usually have a bulging waist 64Tm flic.kr/p/2gz9yX1 (or vice versa). A thin paler greyish longitudinal line often runs across the waist of dark bands. Usually a dark central spot on pale bands. Markings can be partially developed, very indistinct, or absent 63Tm flic.kr/p/2gza7Dt on pale specimens.

4.Dorsal surface of valves has numerous rounded granules visible at X3 magnification, and often to naked eye. Granules tend to follow indistinct growth lines 65Tm flic.kr/p/2gza75x .

5. Dorsal surface of girdle has densely packed rounded granules 65Tm flic.kr/p/2gza75x .

6. Commonest littoral chiton all around Britain. Only chiton species likely to be found higher than MLW on British shores.

7. Usually 16 – 19 ctenidia each side, arrangement almost holobranch 66Tm flic.kr/p/2gz9yUF .

8. White apophyses on intermediate valves are gently curved. Wide curved jugal sinus (gap between them) on valve iv is about same width as one apophysis 67Tm flic.kr/p/2gza6V9 .

 

Callochiton septemvalvis (Montagu, 1803) (Formerly Callochiton achatinus

1. Big species. Max. length 32 mm.

2. Dorsal surface of valves usually some shade of red, sometimes yellow or green, with or without irregular blotches or marbling. Head and tail valves, i and viii, are often darker than the other valves 68Tm flic.kr/p/2gza6TR . Minute black spot (X30 to see) by each apical cap of aesthete canals on valves i and viii, and on lateral triangle of intermediate valves ii to vii 69Tm flic.kr/p/2gz9yHU .

3. Girdle colour is usually a darker shade of the adjacent valve colour, often with a transverse cream band by sutures i/ii and vii/viii 70Tm flic.kr/p/2gz9yyR , and occasionally other sutures 68Tm flic.kr/p/2gza6TR .

4.Dorsal surface of valves has numerous grooves that give a granular appearance visible at X8 magnification 69Tm flic.kr/p/2gz9yHU , but often not visible in photographs.

5. Dorsal surface of girdle has densely packed, tessellated, 200μm long, acicular spicules that create a characteristic snake-skin appearance 71Tm flic.kr/p/2gz9xS5 .

6. Rarely numerous. South, west and north coasts of Britain. Scarce on east coasts; very scarce or absent in southern North Sea and north-east Irish Sea.

7. Usually 20 to 25 ctenidia each side, arrangement merobranch.

8. White apophyses on intermediate valves are short (anterior-posterior), wide and gently curved 72Tm flic.kr/p/2gz9xtu . They meet at the jugum with no jugal sinus (gap) between them. Only British species with two slits and slit rays (sometimes a small third one) in the articulamentum on either side of the imtermediate valves, ii to vii.

 

Habits and ecology

Lives on bedrock and stones at ELWS and sublittorally to about 200 metres, . Four sets of muscles to individual valves 38Tm flic.kr/p/2gzaaV8 , 50Tm flic.kr/p/2gza92J , 51Tm flic.kr/p/2gz9AHL , 52Tm flic.kr/p/2gza8R8 enable shell articulation to conform closely to uneven rock surface. Large muscular foot and flat ventral surface of girdle grip the rock surface firmly 44Tm flic.kr/p/2gzaaj3 . When displaced from the substrate, can use the strong, lateral longitudinal muscle to roll into a protective ball 53Tm flic.kr/p/2gz9AiY .

. Respiration: cilia on ctenidia and mantle create inhalent water-current entering pallial cavity wherever girdle is raised at anterior 30Tm flic.kr/p/2gzacGE . Adjacent ctenidia have interlocking cilia so all work as a unit (as in many bivalves). Water current passes through ctenidia 46Tm flic.kr/p/2gza9Xr and then between foot and ctenidia as exhalent current to posterior where it exits via a channel through the girdle 48Tm flic.kr/p/2gza9pc . Haemolymph (blood) circulates from the head sinus through longitudinal sinuses 46Tm flic.kr/p/2gza9Xr to the mantle, foot, and viscera, then through the ctenidia for aeration before passing into the adjacent heart in the pericardium 48Tm flic.kr/p/2gza9pc below valves vii & viii. From the heart the blood is pumped through the medial dorsal aorta to the head sinus, giving off some channels to the gonad and valve muscles on the way. Chitons lack eyes and tactile/chemoreceptor tentacles on the head. They sense the environment through aesthetes exposed on the surface of the shell (only visible at high magnification) 19Tm flic.kr/p/2gzaed5 , 21Tm flic.kr/p/2gz9FQz & 24Tm flic.kr/p/2gz9FCA . Proposed aesthete functions include chemoreception, mechanoreception, replenishment of properiostracum materials, secretion of protective substances and photoreception, though the focusing lens and receptive retina found in aesthetes of some species are absent from T. marmorea. Sensory organs are also present on the girdle.

T. marmorea feeds by scraping microalgae and associated organisms from the rock surface using its hard magnetite reinforced radula 34Tm flic.kr/p/2gz9DMm & 35Tm flic.kr/p/2gzabKK . In some Scottish sea lochs where it is common, it is an important grazer in the ecosystem (Jones & Baxter, 1987). Though resembling early primitive molluscs in several ways, it has an elaborate digestive system with no trace of primitive rotating style in the stomach. Long coiled intestine compacts faeces into oval pellets 54Tm flic.kr/p/2gz9zHj . Exhalent water current in pallial cavity carries excreta from lateral nephridiopores to posterior, where faecal pellets from anus join the flow; all expelled at posterior through channel in girdle 48Tm flic.kr/p/2gza9pc .

Breeding: dioecious. Water current in pallial cavity carries sperm or ova from lateral gonopores to posterior and out through channel in raised girdle. To facilitate wide dispersal the rear half of the body is raised from the substrate during release 31Tm flic.kr/p/2gz9EjD . As fertilization is external, synchronised emission of sperm and ova is needed to ensure success; trigger in many chiton species is moon-phase/ state of tides. Planktonic trochophore larvae hatch and metamorphose into small adult-form young without intervening veliger stage.

 

Distribution and status

Widely distributed in the northern North Atlantic, Arctic Ocean and White Sea from Novaya Zemlya, Spitzbergen and Baffin Island, Canada southwards to Northumbria and Wales (UK) and Cape Cod (USA). Records from further south need substantiation. Not in Baltic or continental coast of North Sea. Those in north-west Atlantic have some differences from those in north-east Atlantic. There are also records of it in the Pacific southwards to the Sea of Japan (B. Sirenko, in litt.). GBIF map www.gbif.org/species/2306814 . It can be common in Scottish sea lochs; up to 50 /m² (Jones & Baxter, 1987. NBN UK distribution map: species.nbnatlas.org/species/NHMSYS0021056553

 

Acknowledgements

For providing the specimens and/or images for this account I gratefully thank Rob Durrant, David Fenwick, Boyd Forrest, Dr Paula Lightfoot, David McKay, Dr Joanne Porter, Chris Rickard, Allan Rowat, Dr Boris Sirenko and Simon Taylor. I thank Dr Julia Sigwart for her valued specialist advice with the text and interpretation of the images; any errors or omissions are my (IFS) responsibility.

 

Links and references

Baxter, J.M. & Jones, A.M. 1986. Allometric and morphological characteristics of Tonicella marmorea (fabricius, 1780) populations (Mollusca: Polyplacophora: Ischnochitonidae). Zool. J. Linn. Soc. 88: 167 to 177.

 

Botelho, A. 2013. Zoologger: mollusc grows hardest teeth in the world New Scientist 3rd October 2013 www.newscientist.com/article/dn24329-zoologger-mollusc-gr...

 

DORIS website; Tonicella marmorea. Accessed july 2019. doris.ffessm.fr/Especes/Tonicella-marmorea-Chiton-rouge-m...

 

Fernandez, C.Z., Vendrasco, M.J. & Runnegar,B. 2007. Aesthete canal morphology in twelve species of chiton (Polyplacophora). The Veliger 49(2) 51 – 69 www.researchgate.net/publication/246548141_Aesthete_Canal...

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1853) London, van Voorst. (As Chiton marmoreus; Free pdf at archive.org/details/historyofbritish02forbe/page/414 Use slide at base of page to select pp.414 to 417.)

 

Fox, R. 2007. Invertebrate Anatomy On Line. Katharina tunicata lanwebs.lander.edu/faculty/rsfox/invertebrates/katharina....

 

Hayward, P.J. & Ryland, J.S. 1995. Handbook of the marine fauna of north-west Europe. Oxford, Oxford University Press.

 

Jardim, J.A. & Simone, L.R.L. 2010. Redescription of Hanleya brachyplax (Polyplacophora, Hanleyidae) from the south-southeastern Brazilian coast. Pap. Avulsos Zool. (São Paulo) 50 no.40

www.scielo.br/scielo.php?pid=S0031-10492010004000001&...

 

Jeffreys, J.G. 1862-69. British conchology. vol. 3 (1865). London, van Voorst. (As Chiton marmoreus; Free pdf at

archive.org/details/britishconcholog03jeffr/page/226

Use slide at base of page to select pp.227 to 229.)

 

Jones, A.M. & Baxter, J.M. 1987. Molluscs: Caudofoveata, Solenogastres, Polyplacophora and Scaphopoda London, Linnean Society, and Estuarine and Brackish-water Sciences Association.

 

Kaas, P. & Belle, R.A. 1985. Monograph of living chitons Vol 2. Viderup, Denmark. Brill. Preview of Vol1at

books.google.co.uk/books?id=CKautf2EUPkC&pg=PA7&s...

  

Matthews, G. circa1954. The identification of British chitons. Papers for Students No.9. London, Conchological Society of Great Britain and Ireland.

 

Schwabe, E. 2010. Illustrated summary of chiton terminology. Spixiana 33(2):171-194.

Free pdf at verlag-pfeil.de/04biol/pdf/spix33_2_02.pdf

 

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=14015...

  

Glossary

μm = 0.001 mm, 1000μm = 1 mm

acicular = slender and tapering to a point; needle-like.

aesthetes = complex of canals and cavities filled with sensory tissue that permeate tegmentum and locally penetrate articulamentum. Open as sensory pores on dorsal surface of valves; probably compensate for lack of sensory structures on head. Some sense light; other sensory function(s) uncertain, but various authors have variously proposed chemoreception, mechanoreception, properiostracum replenishment and secretion of protective substances.

 

a.k.a. = also known as.

antemedian = (syn. antemedial) situated to anterior of middle.

antemucronal area = area situated to anterior of mucro.

apophysis = (pl. apophyses) anterior extension of articulamentum which underlies preceding valve; on all valves except head valve (i).

 

aragonite = orthorhombic crystalline mineral-form of calcium carbonate www.minerals.net/mineral/aragonite.aspx . Less common on land than calcite, but, currently, the more frequent mineral-form in oceans and living mollusc shells.

 

articulamentum = inner shell-layer of chiton valves, usually hard, white, porcelaneous aragonite and often differently coloured in central part.

 

calcite = trigonal crystalline mineral-form of calcium carbonate www.minerals.net/mineral/calcite.aspx . More common on land than aragonite, but, currently, the less frequent mineral-form in oceans and living mollusc shells. More resistant than aragonite to acid rain corrosion; forms outer shell layer of shore-dwelling Littorina species in cool climates. (Corrosion of calcium carbonate faster at cold temperatures).

 

cephalic = (adj.) of or on the head.

chemoreception = sensing of chemicals; “smell / taste”.

chitin = semitransparent flexible horny protein. Does not occur in molluscs.

 

chitinous = (adj.) resembling chitin.

cilia (pl.) = motile linear extensions of membrane used in locomotion, or to create water currents in feeding. (“cilium” singular).

 

coll. = in the collection of (named person or institution) (cf. legit).

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

 

dioecious = having separate male and female individuals.

dorso-ventrally flattened = as if pressed flat from above.

ELWS = extreme low water spring tide (usually near equinoxes).

epithelium = tissue forming outer layer of body surface, “skin”.

 

girdle = (on chiton) peripheral band of thickened, reflexed mantle that encloses ends of valves.

 

gonopore = genital opening through which eggs or sperm are released.

holobranch = (of chitons) ctenidia in mantle cavity extend full length of foot.

hyponotum = ventral cuticle of chiton’s girdle.

insertion plate = (on most chitons) extension of articulamentum which inserts into mantle on lateral margin of intermediate valves, anterior margin of head valve and posterior margin of tail valve. Inserts into, and anchors valve to, the girdle muscle block.

 

intermediate valve = (of chiton) any valve (ii – vii), except head valve (i) and tail valve (viii).

 

jugal area = summit zone of chiton valves on dorsal surface.

jugal tract = summit zone of chiton valves on ventral surface.

jugum = summit of chiton valves.

lateral area = (on intermediate valve of chiton) triangular area with its base along lateral edge of valve and its apex near the centre of the posterior edge. a.k.a. lateral triangle.

 

legit = (abbreviation; leg. or lgt.) collected/ found by (cf. coll.)

LWS = low water spring tide, two periods of a few days each month when tide falls lowest.

 

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

mantle cavity = (on chitons) a.k.a. pallial groove; narrow groove around whole foot and head, roofed by mantle and containing ctenidia, nephridiopores and gonopores.

 

magnetite = mineral of iron oxide, hardest material made by any living organism.

marmorated = veined or streaked like marble.

mechanoreception = sensing of touch, sound, pressure change and/or posture.

 

MLW = mean low water mark.

 

merobranch = (of chitons) gills in pallial cavity only in posterior two-thirds of animal.

 

mucro = projection on tail valve (viii) of chiton demarking posterior from rest of valve. Varies in prominence and position.

 

myostracum = thin, inconspicuous, discontinuous, innermost layer of chiton shell.

 

nephridium = tubular glandular excretory/ osmoregulatory organ. a.k.a. kidney.

 

nephridiopore = opening of nephridium for excretion. a.k.a. renal pore.

odontophore = firm, approximately ellipsoid, structure of cartilage supporting radula. Protruded like a tongue to operate radula.

 

pericardium = membranous sac containing heart and start of aorta.

perinotum = dorsal cuticle of chiton’s girdle.

pleural area = (on intermediate valve of chiton) triangular area with its base along anterior edge of valve and its apex near the centre of the posterior edge. a.k.a. median triangle.

 

postmucronal = situated to posterior of mucro.

properiostracum = (on chitons) outermost layer of colour-bearing proteinaceous material, sometimes resembling collagen in texture and differing in composition from periostracum of most other mollusc groups.

 

plankton = animals and plants that drift in pelagic zone (main body of water).

radula = chitinous ribbon of teeth extruded on a tongue-like structure (odontophore) to rasp food.

 

side slope = (on chiton) shape in profile view (from posterior or anterior) of lateral areas of intermediate valves; may be straight, convex, concave or a combination of these.

 

sinus = 1. dilated channel or receptacle containing blood etc. 2. (re. chiton valves) curved bay or gap.

slit ray = row of canal pores running diagonally from lateral slit to posterior edge on ventral surface of chiton valve. a.k.a. notch ray.

 

suture = (of chiton) line where two valves meet.

tegmentum = outer shell-layer of chiton valves, usually porous and relatively soft. (Covered by transparent properiostracum when live.)

 

trochophore = spherical or pear-shaped larvae that swim with aid of girdle of cilia. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for limpets, Trochidae, Tricolia pullus and (with no veligers) chitons.

 

uncinate = having a hooked shape.

uncinate blades = largest two teeth in each row of seventeen on chiton radulae; principal scraping blades. Often darkened more than other teeth by high magnetite content.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

Simon & Schuster/Pocket Books 1985, 316 pages, pages, map, glossary, photographs, 316 pages, ISBN 0-671-61750-8, trade paperback

 

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When in water (right), shell is more translucent, lighter and brighter in colour, and less reflective, than when in air (left).

1: internal view of row of palatal protrusions at earlier position of palatal lip.

2: external view through translucent shell of same row of protrusions as in ‘1’.

Shell height 6.1 mm. Salting on tidal River Dee, Flintshire, Wales. December 2018.

Full DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

GLOSSARY BELOW

Preface

Specimens illustrated in this account which were supplied to Amgueddfa Cymru (the Natural History Museum, Wales) were sequenced by Ben Rowson who found no difference in the DNA of M. myosotis and M. denticulata and concluded that they were a single species; Myosotella myosotis (Draparnaud, 1801). This has been accepted by WoRMS; see www.marinespecies.org/aphia.php?p=taxdetails&id=139672 ]

A possibility, raised by Martins (2013), is that the true M. myosotis (Draparnaud, 1801) occurs in the Mediterranean and that both British shell forms are ecotypes of M. denticulata (Montagu, 1803). This account, written before molecular sequencing united them, describes the form previously regarded as M. denticulata.

Because of its special habitat intermediate between terrestrial and marine, this species, and its Leucophytia relative in the family Ellobiidae, are omitted from some identification guides, while variously appearing in others devoted solely to either terrestrial, marine or even freshwater mollusca.

 

Myosotella myosotis form denticulata (Montagu, 1803)

Synonyms: Voluta denticulata Montagu, 1803; Voluta ringens W. Turton, 1819; Ovatella denticulata (Montagu, 1803); Alexia ringicula Locard, 1893; Conovulus denticulatus in Forbes & Hanley (1853); Melampus myosotis (part of) in Jeffreys (1869);

Vernacular Probably applied at times to both M. denticulata and M. myosotis: Mouse-eared Alexia, Mouse ear(ed) snail (English); Clust llygoden (Welsh); Evesnegl (Danish); Muizenoortje (Dutch); Ovatelle naine des vases (French); Stranddvärgsnäcka (Swedish); Mäuseöhrchen (German);

Applied to just this form: Many-toothed mouse-ear (English); Gewoon muizenoortje (Dutch);

 

Description

When in water, shell is more translucent, lighter and brighter in colour, and less reflective, than when in air 1Md flic.kr/p/2ejw2rW . The following shell description is of specimens in air.

Shell

Juvenile shell usually less than 6 mm high. Adult shells often less than 6mm , usual maximum 7.5 mm, exceptionally 10 mm 2Md flic.kr/p/24NUBLV . Fusiform shell, width c.45% to 55% of height 3Md flic.kr/p/2fkP2h7 . Small spire with sharp apex; body whorl c. 73% of shell height, usually a little less on small specimens. Apex slightly twisted 3Md flic.kr/p/2fkP2h7 due to change from sinistral protoconch to dextral teleoconch. Shell-wall thin, opaque or slightly translucent, with a silky sheen when clean 4Md flic.kr/p/2fkP21f . Up to 8 moderately convex whorls separated by distinct shallow sutures. On juveniles, the periostracum is drawn into a row of bristles below the sutures 5Md flic.kr/p/2fkP1V5 , but they are worn off over time. Earliest juveniles with three or fewer whorls lack periostracum and bristles; their shells are white-translucent with punctate spiral lines which may persist for a time as the shell grows ; occasionally visible through periostracum on later whorls 6Md flic.kr/p/2fkP1HS . Very fine, closely spaced, costal lines sometimes visible on adults, especially on spire whorls 6Md flic.kr/p/2fkP1HS , often most clearly developed on subsutural ramp 4Md flic.kr/p/2fkP21f . Adults have growth lines; most easily seen when periostracum is worn 3Md flic.kr/p/2fkP2h7 , less so when periostracum is intact 7Md flic.kr/p/2fkP1Gj . Usually no umbilicus except for an umbilicus-like slit in the apex caused by the change from the sinistral larval shell (protoconch) to a dextral shell 8Md flic.kr/p/2fqtbmD . Within the shell, when it reaches 2½ whorls, the columella and septa between the spire whorls are resorbed by the mantle, leaving an open space except for the columella and septum of the body whorl. Aperture 50% to 60% of shell height 3Md flic.kr/p/2fkP2h7 , juveniles usually nearer the higher limit; shaped like a narrow ear with a rounded base and a sharp adapical angle 2Md flic.kr/p/24NUBLV . Thin palatal (outer) lip on specimens over 3mm high has two to seven (or more) protrusions (folds/teeth/denticles) 2Md flic.kr/p/24NUBLV which may be set into a pale calcareous ridge within the aperture near the palatal rim. Further sets of protrusions are often present further back in the aperture, marking previous positions of palatal lip 2Md flic.kr/p/24NUBLV . The palatal lip is sometimes weakly reflected on large adults 9Md flic.kr/p/2fkP1kN . The columellar-parietal lip (inner lip of aperture) has three or four protrusions . The parietal lip consists of a wide glazed area on the body whorl, but is often difficult to discern 2Md flic.kr/p/24NUBLV & 10Md flic.kr/p/2fkNZXU . Juveniles less than 3mm high may not have developed protrusions sufficiently to be distinguished from M. myosotis. For a clear view of the features within the aperture, including far-back rows of teeth, the animal may need a prod with a small brush to make it withdraw, and the shell requires tilting at different angles 11Md flic.kr/p/2fkNZsA . There is no operculum . Exterior colour varies from yellowish brown to brown 2Md flic.kr/p/24NUBLV . The protoconch and juvenile shell up to about 1.4mm height are white, and are retained as a white apex on the adult 3Md flic.kr/p/2fkP2h7 & 14Md flic.kr/p/2fkNZ4E . On dead stranded shells the periostracum often peels off and the colour bleaches to whitish 10Md flic.kr/p/2fkNZXU .

Body

Specimens from non-salting conditions have white or very pale grey flesh; colour on an individual varies with degree of extension and whether in air or water 12Md flic.kr/p/2fkNZeE . The colour of the occasional ones from under stones on saltings is similar to that of M. myosotis with darker grey arranged in transverse bands across the dorsum, and colour intensity usually increases with size/age 13Md flic.kr/p/RE4vht . The tentacles on all forms are usually grey or greyish. Sides of foot are paler than the dorsum of grey specimens 12Md flic.kr/p/2fkNZeE & 13Md flic.kr/p/RE4vht . The mantle sometimes projects a short way beyond the aperture rim of the palatal lip, but is not reflected onto it 13Md flic.kr/p/RE4vht . The parietal lip on the body whorl is a glaze formed by the mantle extending onto it 2Md flic.kr/p/24NUBLV & 10Md flic.kr/p/2fkNZXU . The mantle cavity, the roof of which contains a network of haemolymph vessels 14Md flic.kr/p/2fkNZ4E , functions as a lung for respiration. It is sealed off from the exterior by a thick, white or brownish-white, mantle-collar which fits closely round the body as it extends or retracts 6Md flic.kr/p/2fkP1HS & 24Md flic.kr/p/2e2z6Ja . The collar has a pneumostome which, when in air, can be opened and closed 15Md flic.kr/p/2fqt9Jk for respiration and humidity control but, when immersed, does not effectively retain air or exclude water 16Md flic.kr/p/RE4uWD & 17Md flic.kr/p/2fqt9ta . The rectum and part of the intestine, visible through translucent shells in water 17Md flic.kr/p/2fqt9ta , runs along the rear edge of the roof of the mantle cavity to the anus 18Md flic.kr/p/2e2z6XM which opens to the exterior in a folded part of the mantle-collar in the adapical angle of the aperture close to the pneumostome . The head has two cephalic tentacles; nearly linear with a bluntly pointed tip (subulate) when dry, and conical and paler when swollen with water 13Md flic.kr/p/RE4vht . When not fully extended, they are contracted, becoming annulated in the basal half 19Md flic.kr/p/2fkNYE3 , not retracted by inversion into the body. The tentacles widely diverge from their bases near the midline of the head 20Md flic.kr/p/2e2z6TZ . The distal half of the tentacles, sometimes slightly bulbous, is opaque grey, sometimes with a brownish tint 21Md flic.kr/p/2fkNYzU , and contains sensory chemoreceptor cells (Wondrak, 1984). There is an internal black eye within the posteromesial base of each tentacle 19Md flic.kr/p/2fkNYE3 . The head in front of the tentacles forms a broad, slightly bilobed “muzzle” (Forbes & Hanley,1853) 22Md flic.kr/p/2e2z6LV which can be variably configured, but not cylindrically to form a snout like that of many marine gastropods. Near the anterior edge of the muzzle are two button-like, pads (“fungiform bodies” of Wondrak, 1984) which contain sensory cells 21Md flic.kr/p/2fkNYzU , but they are inconspicuous on animals with white flesh. Ventrally, the mouth is protected by white outer-lip lobes. When feeding, the ventrally translucent-white muzzle is spread out flat on the substrate and the outer lips moved aside to expose the mouth edged anteriorly by the rim of the red-brown jaw 23Md flic.kr/p/24NUzJ8 , and to allow the extension of the anterior of the radula covered in thousands of white teeth. When translucent, the muzzle may reveal dorsally the oral tube leading from the mouth to the buccal mass, and the oesophagus passing from it towards the stomach 20Md flic.kr/p/2e2z6TZ . On weakly pigmented, translucent specimens the dumbbell-shaped, dorsal part of the nerve ring with two cerebral ganglia may be visible 20Md flic.kr/p/2e2z6TZ . The ring encircles the oesophagus. It and its ganglia that innervate organs on the head are the nearest approximation in gastropods to a centralised brain, but other ganglia distributed on nerve cords around the body innervate other organs. The anterior edge of the translucent white sole is broad and gently curved or almost straight, sometimes with a slightly indented middle, and tapers to a rounded posterior 22Md flic.kr/p/2e2z6LV . M. denticulata is a protandrous hermaphrodite. The common genital aperture is hidden beneath the mantle on the right of the animal. The female opening is covered by a thin lip of integument which continues forwards as a narrow fold enclosing the vas deferens 18Md flic.kr/p/2e2z6XM to the male aperture on the right of the head from which penis with vas deferens can be everted for mating by hydrostatic pressure of haemolymph.

When immersed in water, the body absorbs water, swells, and it and the shell become paler and more translucent, sometimes, revealing internal organs 24Md flic.kr/p/2e2z6Ja , 17Md flic.kr/p/2fqt9ta ,18Md flic.kr/p/2e2z6XM & 20Md flic.kr/p/2e2z6TZ . A dissection was not made for this species/ecotype. Most published anatomy accounts are of M. Myosotis sensu lato which includes this species. Dissections can be seen of M. myosotis in its account at flic.kr/s/aHsmv1sTC7 images 32 to 37.

 

Key identification features

Features 1 to 4, below, accord with Forbes & Hanley (1853) and Gittenberger (2004). The former aggregated M. myosotis sensu stricto with M. denticulata but “scrupulously kept apart their description.” Many currently used identification guides aggregate them and their features under M. myosotis sensu lato. Consequently, distribution maps on GBIF and NBN include many M. denticulata occurrences under “M. myosotis”, and the M. denticulata maps have under-representation of its occurrence.

To observe aperture sculpture the animal must be well withdrawn, and the shell tilted at different angles. Sometimes the outer (palatal) lip sculpture of an earlier growth stage is visible deep into the aperture and should be used if the sculpture on new growth has not yet developed. It is advisable to examine several specimens of different sizes from a site; sometimes both are present..

 

Myosotella denticulata(Montagu, 1803).

1. Live shell brown (beachworn shells may be dull whitish). Usual adult height 3.5 mm to 7.5 mm, exceptionally 10 mm 2Md flic.kr/p/24NUBLV .

2. Inner (columellar/parietal) lip has 3 or 4 apertural protrusions 2Md flic.kr/p/24NUBLV .

3.Outer (palatal) lip has 2 to 7 (or more) apertural protrusions 2Md flic.kr/p/24NUBLV sometimes set into a pale ridge which occasionally submerges them. [If no protrusions, check further back in aperture for protrusions on earlier lip position; may be visible from exterior through translucent shell, with or without connecting streaks.]

4. In its typical non-salting habitat, the flesh colour of normally extended dorsal body is white or very pale whitish grey, with darker grey tentacles 12Md flic.kr/p/2fkNZeE . But when it occurs in muddier conditions, it may be as dark as M. myosotis 13Md flic.kr/p/RE4vht .

5. Habitat: typically under slightly embedded stones at Extreme High Water Spring level and above (supralittoral) on sheltered coast without salting vegetation at fully marine salinity. Occasionally under stones on landward edge of Saltmarsh-grass sward by tidal rivers with low salinity 25Md flic.kr/p/2fkNYuy .

 

Similar species/ecotype

Myosotella myosotis

(Full account flic.kr/s/aHsmv1sTC7 )

1. Live shell brown 28Md flic.kr/p/2fqt7di (beachworn shells may be dull whitish 29Md flic.kr/p/RE4sZH ). Usual adult height 6.5mm to 8mm, exceptionally 10mm .

2. Inner (columellar/parietal) lip has only 2 or 3 apertural protrusions 30Md flic.kr/p/2ejvWdQ .

3. Outer (palatal) lip has a single apertural denticle or none 30Md flic.kr/p/2ejvWdQ . Some have a pale apertural ridge running close to the lip.

4. Flesh colour of normally extended dorsal body is grey 31Md flic.kr/p/2e2z4yD . Shade and intensity varies with age, extension and whether in air or water, but not pure white when adult.

5. Habitat: among vegetation, often under driftwood, on low salinity estuarine saltings and Saltmarsh-grass sward by tidal rivers a little above and below EHWS. Locally abundant. (May occur with M. denticulata under stones on/near saltings 25Md flic.kr/p/2fkNYuy .)

 

Leucophytia bidentata (Montagu, 1808).

(Full account flic.kr/s/aHsmwhDvaL )

1. Live shell slightly-translucent ivory-white; yellow viscera may show through spire 32Md flic.kr/p/24NUy3H . Usual adult height to 5 mm, occasionally to 7 mm. Sutures shallower and whorls less rounded than on M. myosotis 33Md flic.kr/p/2e2z4hB .

2. Inner (columellar/parietal) lip has 2 protrusions within the aperture; not more 33Md flic.kr/p/2e2z4hB .

3. Outer (palatal) lip has no protrusions or rib (sometimes in a photo, a strong growth line might be mistaken for a rib 33Md flic.kr/p/2e2z4hB .

4. Flesh colour of normally extended dorsal body is almost pure white 32Md flic.kr/p/24NUy3H , but when contracted into body-whorl colour saturation gives it a cream appearance.

5. Lives in deep, silty, rock crevices between High Water Neap level and Low Water Spring level. Also under stones embedded into soil-like substrate at Extreme High Water Spring level and a little above on sheltered coast where it is often with M. denticulata.

 

Habits and ecology

M. denticulata lives typically under slightly embedded stones at Extreme High Water Spring level and slightly above (supralittoral) on sheltered coast without salting vegetation at fully marine salinity; often in company with Leucophytia bidentata and some terrestrial invertebrates. Occasionally, it also occurs under stones on the landward edge of Saltmarsh-grass sward by tidal rivers with low salinity 25Md flic.kr/p/2fkNYuy , often with more numerous M. myosotis, Assiminea grayana and some terrestrial invertebrates. It does not live in permanently submerged in pools, but can survive and be active for short periods of immersion. As there is no operculum to reduce dessication, the species is an obligatory hygrophile. Its spindle shaped shell is well adapted for moving through small gaps under stones. When moving, the foot and shell are cushioned on a layer of watery mucus which is sometimes mistaken for the foot 26Md flic.kr/p/2fqt7pv & 27Md flic.kr/p/RE4tge which usually underlies little more than the aperture . M. denticulata senses its surroundings with its tentacles and the two button-like pads (“fungiform bodies” of Wondrak, 1984) 21Md flic.kr/p/2fkNYzU near the anterior edge of the muzzle. In its usually dark habitat, its eyes probably function as little more than light detectors to trigger negative phototaxic motion when exposed to light.

It is a euryhaline species capable of surviving immersion in water from 0 p.p.t to full marine salinity or more, but individuals require time to adapt to changes in salinity and may become inactive/moribund when abruptly immersed in water they are unaccustomed to.

Respiration is of atmospheric air in the mantle cavity which is sealed by a collar of thickened mantle 6Md flic.kr/p/2fkP1HS that firmly embraces the body but allows it to extend-from/retract-into the shell 24Md flic.kr/p/2e2z6Ja . A pneumostome (respiratory pore) in the collar 15Md flic.kr/p/2fqt9Jk can be opened for inhalation/exhalation of air or closed to seal the cavity against dehydration. The roof of the mantle cavity contains a network of haemolymph vessels 14Md flic.kr/p/2fkNZ4E and is very thin, enabling oxygen from inhaled air to diffuse into the vessels and for carbon dioxide to leave with the exhaled air. When immersed, air escapes 17Md flic.kr/p/2fqt9ta from the mantle cavity and water enters as the pneumostome is not tightly closed 16Md flic.kr/p/RE4uWD .

When feeding, the muzzle is spread out on the substrate and the radula is extended 23Md flic.kr/p/24NUzJ8 to gather, with the red jaw as a backstop, decaying vegetation, diatoms (Wiese & Richling, 2008) and sediment rich in organic material which are bound into food boli with mucus from the supra pedal gland brought to the mouth along a median groove. Unlike marine prosobranch gastropods, which defecate into a mantle cavity that is cleared by water currents, M. denticulata has a rectum that opens to the exterior through an anus in the mantle collar 18Md flic.kr/p/2e2z6XM , near to, but separate from, the pneumostome so that faeces are expelled without fouling the respiratory mantle-cavity. The soft faeces are wet and loosely bound with mucus when fresh 27Md flic.kr/p/RE4tge . There is no operculum 11Md flic.kr/p/2fkNZsA to provide protection against intrusion by predators, but the numerous protrusions narrow the aperture to impede attack. The aperture protrusions of M. denticulata may have developed in response to the different (more threatening?) predators present in its habitat, which is more terrestrial than that of M. myosotis.

Reproduction: (Details assumed from published accounts of M. myosotis sensu lato.) M. denticulata is a protandrous hermaphrodite which changes its sexual function in the wild when 1½ to 2 years old, so younger, 1 to 1½ years, fully mature males mate with older, over 1½ years, females (Schultes, 2014) using the stout, conical penis everted from the side near the posterior of the right tentacle. Female deposits 15 to 80 egg capsules in a small, yellow or white, frog-spawn-like mass (Morton, 1954 and Gittenberger, 2004). Each ovoid capsule contains a single ovum. The cases are attached to each other in a loosely convoluted chain by a filament (chalaziform process) at each end. The closely packed cases with intervening clear fluid are contained in a tough binding membrane which is attached to stones. There is a larval veliger stage, with sinistral shell, which is passed entirely within the ovum (Morton, 1954).

 

Distribution and status

Europe from England to Mediterranean and Azores. GBIF map, www.gbif.org/species/4359191

Locally common in suitable habitat with rocks in Britain but records from vegetated saltings are likely to be the species/ecotype M. myosotis sensu stricto. NBN map

species.nbnatlas.org/species/NHMSYS0001702111

Irish distribution, National biodiversity data centre, in Mollusc Ireland: www.habitas.org.uk/molluscireland/species.asp?ID=121

 

Acknowledgements

I gratefully thank Ben Rowson of the National Museum Wales for his help with the account, but any errors or omissions are mine.

 

Links and references

 

Anderson, R. MolluscIreland, accessed January 2019. www.habitas.org.uk/molluscireland/species.asp?ID=121

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 4 (1853), 190 – 197 & plate CXXV. London, van Voorst. (AsConovulus denticulatus var. myosotis.)

Free pdf at archive.org/details/historyofbritish04forbe/page/190

plate at archive.org/details/historyofbritish04forbe/page/n565

 

Fretter, V. & Peake, J. 1975. Pulmonates functional anatomy and physiology. Vol.1. London. Academic Press.

 

Gittenberger, E. et al. 2004. De Nederlandse zoetwatermollusken. Leiden, Netherlands, Nationaal Natuurhistorisch Museum Naturalis.

 

Heller J. 2015. Marine Ancestors of most Land Snails: Pulmonates. In: Sea Snails. Springer, Cham. link.springer.com/chapter/10.1007%2F978-3-319-15452-7_10

 

Jeffreys, J.G. 1862-69. British conchology. vol. 5 (1869). London, van Voorst. (As Melampus myosotis (including var. ringens = Myosotella denticulata); Free pdf at archive.org/stream/britishconcholog05jeffr#page/106/mode/2up . Use slide at base of page to select pp.106-109.)

 

Martins, A.M. de F. 1996. Anatomy and systematics of the western Atlantic Ellobidae (Gastropoda: Pulmonata). Malacologia 37(2): 163 – 332.

www.biodiversitylibrary.org/page/13113594#page/179/mode/1up

 

Martins, A.M. de F. & Mendes, A.R.M. 2013. Do cosmopolitans speciate? Anatomical diversity of Myosotella in Azores. Centro de Investigação em Biodiversidade e Recursos Genéticos. Ponta Delgada, Açores, Portugal. Poster for World Congress of Malacology 2013 in pdf: www.researchgate.net/publication/264339925_Do_cosmopolita... .

 

Montagu, G. 1808. Supplement to: 1803 Testacea Britannica, or, Natural history of British shells, marine, land, and fresh-water, including the most minute : systematically arranged and embellished with figures. London, J. White.

Description of Leucophtia bidentata as Voluta bidentata pp. 100-101.

www.biodiversitylibrary.org/page/24430722#page/806/mode/1up

Plate 30, fig.2:

www.biodiversitylibrary.org/page/24430722#page/917/mode/1up

  

Morton, J. E. 1955. The functional morphology of the British Ellobiidae (Gastropoda Pulmonata) with special reference to the digestive and reproductive systems. Phil. Trans. R. Soc. Ser. B .

239, No. 661: 89-160 www.jstor.org/stable/92507

 

Schultes, F.W. 2014. Species summary for Ovatella myosotis (Draparnoud, 1801). AnimalBase. SUB Göttingen. www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBas... Accessed January 2019.

 

Watson, H. I943. Notes on a list of the British non-marine Mollusca. J. Conch. 22: 13 - 22.

 

Wiese, V. & Richling, I. 2008. Das Mäuseöhrchen Myosotella myosotis (Draparnaud 1801). Arbeitskreis Mollusken NRW.

www.mollusken-nrw.de/weichtier_des_jahres/weichtier2008.htm

 

Wondrak, G. 1984. Ultrastructure of the sensory epithelia of oral tube, fungiform sensory bodies, and terminal knobs of tentacles of Ovatella

myosotis. Draparnaud (Archaeopulmonata, Gastropoda) J. Morphol. 181: 333-347 .

onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.1051810307

 

Current taxonomy:

www.marinespecies.org/aphia.php?p=taxdetails&id=139673

 

Glossary

adapical angle = angle at which outer lip meets body-whorl.

boli = (sing. bolus) small rounded masses, especially of triturated food material.

cerebral = to do with integration of sensory and neural functions to initiate and coordinate body activity.

chalaziform = resembling the two spiral bands (chalazae) in a bird's egg that attach the yolk to opposite ends of the lining membrane.

 

columella = solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.

 

columellar = (adj.) of or near central axis of coiled gastropod.

columellar lip = lower (abapical) part of inner lip of aperture.

costa (pl. costae) = rib running across a whorl of a gastropod shell at approximately right-angles to direction of coiling and any spiral striae.

 

costal (adj.) = of, or arranged like, costae.

dextral = (of gastropod shell) in apertural view with spire uppermost, the aperture is on the right. Most gastropod species adults have dextral shells.

 

distal = away from centre of body or from point of attachment.

diverticula = (for digestion) blind ended tubules in the digestive gland that receive nutrients for digestion.

 

EHWS = extreme high water spring tide.

euryhaline = able to tolerate a wide variation in salinty.

fusiform = slender, spindle-shaped, tapering almost equally towards both ends.

 

ganglia = (sing. ganglion) knots on a nerve cord containing sensory cell bodies that conduct impulses to (innervate) organs of the body.

 

haemolymph = circulating fluid in molluscs that carries nutrients, waste and hormones. Analagous to vertebrate blood, but most molluscs have copper-based haemocyanin in it instead of red haemoglobin to carry oxygen. It may be tinged blue when oxygenated; colourless when depleted of oxygen.

 

halophyte = plant tolerant of saline soil and periodic tidal immersion, usually on saltmarshes, estuarine shores and sides of tidal rivers.

 

hygrophile = living in moist, humid, but not submerged, conditions.

(obligatory hygrophile = only able to live in such conditions.)

 

mantle = sheet of tissue that secretes the shell, covers the viscera and forms a cavity in gastropods. In terrestrial gastropods ('pulmonates') the cavity roof contains a network of haemolymph ('blood') vessels enabling the cavity to act like a lung.

 

mesial = on or facing towards the midline of the body.

operculum = plate of horny conchiolin, rarely calcareous, used to close shell aperture of prosobranch gastropods.

 

palatal lip = outer lip of gastropod aperture.

parietal lip ( or parietal wall) = upper part of inner side of gastropod aperture, often lacking clear lip structure with just a glaze on side of whorl adapically of columellar lip.

 

periostracum = thin horny layer of proteinaceous material often coating shells.

posteromesial = at the rear facing towards the midline of the body.

prosobranch = member of Prosobranchia, one of three subclasses into which the class Gastropoda (slugs and snails) was divided during the 20th Century (other two were Pulmonata and Opisthobranchia). This classification is no longer used by scientists, but prosobranch is a useful informal term to signify (mainly marine) snails breathing with a ctenidium (comblike gill inside mantle cavity), an operculum, and a shell which can accommodate the whole body.

 

protandrous hermaphrodite = each individual starts mature life as a functioning male, later changing to female function.

 

protoconch = apical whorls produced during embryonic and larval stages of gastropod; often different in form from other whorls (teleoconch).

 

protrusions = teeth, denticles, folds, lamellae or cogs (terms used by various authors).

 

punctate = with pinprick-like depressions.

resorb = absorb what was previously secreted; break it down into component materials and disperse into the circulation.

 

resorption = the process of absorbing what was previously secreted by breaking it down into component materials and dispersal into the circulation.

 

salting = area of salt tolerant vascular plants rooted in sediment between mean high water mark (MHW) and extreme high water of spring tides (EHWS). [Preferred synonym for “saltmarsh” as much of salting not marshy.]

 

septa = plural of septum; internal partition separating two chambers/ shell-whorls of a gastropod.

 

septum = internal partition separating two chambers/ shell-whorls of a gastropod.

 

sinistral = (of gastropod shell) in apertural view with spire uppermost, the aperture is on the left. Most gastropod species adults have dextral shells.

 

subsutural = close below the suture when shell positioned with apex uppermost.

 

subulate = slender and tapering to a point like onion leaf or awl.

suture = groove or line where whorls of gastropod shell adjoin.

teleoconch = entire gastropod shell other than the apical, embryonic & larval stage protoconch.

 

triturate = reduce to small particles.

vascular plants = plants that have vascular tissues to transport water and nutrients through the plant. Include all seed-bearing plants, ferns and horsetails. Usually terrestrial or in freshwater or brackish water; a few, such as Zostera, live in fully marine salinity water.

  

Rama (IAST: rāma, Devanāgarī: राम, Khmer: Phreah Ream, Thai: Phra Ram, Lao: Phra Lam, Tagalog: Rajah Bantugan) or Ramachandra was a legendary king of Ayodhya in ancient India. In Hinduism,[1] he is considered to be an avatar of Vishnu[2] and a lila-avatara as described in the Bhagavata Purana.[3]

 

Rama is one of the most popular figures and deities in Vaishnavism and Vaishnava religious scriptures in South and Southeast Asia.[4] The majority of details concerning Rama come from the Ramayana, one of the two great epics of India.[5] Born as the eldest son of Kaushalya and Dasharatha, king of Ayodhya, Rama is referred to within Hinduism as Maryada Purushottama,[6] literally the Perfect Man or Lord of Restrictions.[7] Rama is the husband of Sita, who Hindus consider to be an Avatar of Lakshmi and the embodiment of perfect womanhood.[6][8]

 

Rama's life and journey is one of perfect adherence to dharma despite harsh tests of life and time. For the sake of his father's honour, Rama abandons his claim to Kosala's throne to serve an exile of fourteen years in the forest.[9] His wife, Sita and brother, Lakshmana being unable to live without Rama decide to join him, and all three spend the fourteen years in exile together. This leads to the kidnapping of Sita by Ravana, the Rakshasa monarch of Lanka. After a long and arduous search that tests his personal strength and virtue, Rama fights a colossal war against Ravana's armies. In a war of powerful and magical beings, greatly destructive weaponry and battles, Rama slays Ravana in battle and liberates his wife. Having completed his exile, Rama returns to be crowned King in Ayodhya (the capital of his Kingdom) and eventually becomes Emperor of the World,[9] after which he reigns for eleven thousand years – an era of perfect happiness, peace, prosperity and justice known as Rama Rajya.

 

Rama's courage in searching for Sita and fighting a terrible war to rescue his wife and their honour is complemented by Sita's absolute devotion to her husband's love, and perfect chastity despite being Ravana's captive. Rama's younger brothers, namely Lakshmana, Shatrughna and Bharata strongly complement his piety, virtue and strength,[9] and they are believed by many to belong to the Mariyada Purshottama and the Seventh Avatara, mainly embodied by Rama. Rama's piety and virtue attract powerful and devoted allies such as Hanuman and the Vanaras of Kishkindha, with whose help he rescues Sita.[9] The legend of Rama is deeply influential and popular in the societies of the Indian subcontinent and across South East Asia. Rama is revered for his unending compassion,[10] courage and devotion to religious values and duty.

 

Contents [hide]

1 Etymology

2 Literary sources

3 Avatara

4 Prince of Ayodhya

5 Initiation of the Avatara

5.1 Another version

6 Dharma of exile

7 Rama and Sita

7.1 Agni pariksha

7.2 Sita's banishment

8 Maryada Purushottama

9 Rama and non-violence

10 Companions

10.1 Bharata and Lakshmana

10.2 Jatayu, Hanuman and Vibheeshana

11 Rama in war

11.1 Sagara

11.2 Facing Ravana

12 Rama Rajya

13 Rama and the world

13.1 Festivals of Lord Rama

13.2 Inspiration

14 Notes

15 References

16 External links

   

Etymology

Part of a series on

Hinduism

  

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Denominations

Literature

 

Beliefs and practices

Dharma · Artha · Moksha · Karma · Samsara

Yoga · Bhakti · Maya

Puja · Mandir

 

Scriptures

Vedas

Ramayana · Mahabharata

Tevaram · Divya Prabandha

Bhagavad Gita · Purana

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Rāmá in the Rigveda and the Atharvaveda is an adjective meaning "dark, black", or a noun meaning "darkness", e.g. RV 10.3.3 (trans. Griffith):

 

10.3.3cd Agni, far-spreading with conspicuous lustre, hath compassed Night [Rama] with whitely shining garments.

Rama is made up of 'Ra' + 'ama' which means light coming from within.

 

As a personal name it appears in RV 10.93.14:

 

10.93.14ab This to Duhsima Prthavana have I sung, to Vena, Rama, to the nobles [Asuras], and the King.

The feminine form of the adjective, rāmīˊ is an epitheton of the night (Ratri), as is kṛṣṇīˊ, the feminine of kṛṣṇa, viz. "the dark one; the black one". Mayrhofer (1996) suggests a derivation from PIE (H)reh1-mo-, cognate to OHG rāmac "dirty".

 

Two Ramas are mentioned in the Vedas, with the patronymics Mārgaveya and Aupatasvini; another Rama with the patronymic Jāmadagnya is the supposed author of a Rigvedic hymn. According to Monier-Williams, three Ramas were celebrated in post-Vedic times,

 

Rāma-chandra ("Rama-moon"), son of Dasaratha, believed to have descended from Raghu[citation needed]. (The Rama of this article).

Parashu-rāma ("Rama of the Battle-axe"), the Sixth Avatara of Vishnu, sometimes also referred to as Jāmadagnya, or as Bhārgava Rāma (descended from Bhrigu), a "Chiranjeevi" or Immortal.

Bala-rāma ("the strong Rama"), also called Halāyudha (Wielder of the Plough in Battle), the older brother and close companion of Krishna, the Eighth Avatara of Vishnu.

In the Vishnu sahasranama, Rama is the 394th name of Vishnu. In the interpretation of Adi Sankara's commentary, translated by Swami Tapasyananda of the Ramakrishna Mission, Rama has two meanings: the supreme Brahman who is the eternally blissful spiritual Self in whom yogis delight or the One (i.e., Vishnu) who out of his own will assumed the enchanting form of Rama, the son of Dasaratha.

  

Literary sources

The primary source of the life and journey of Rama is the epic Ramayana as composed by the Rishi Valmiki. However, other scriptures in Sanskrit reflect the life of Ramayana. For example, the Vishnu Purana also recounts Rama as Vishnu's seventh avatara and in the Vayu Purana, a Rama is mentioned among the seven Rishis of the 8th Manvantara. Additionally, the tales of Rama are reverently spoken of in the later epic, the Mahabharata. Another important shortened version of the epic in Sanskrit is the Aadhyaatma Ramayana.

 

The epic had many versions across India's regions. For example, vernacular versions of the Ramayana which include the life, deeds and divine philosophies of Rama are elaborated in the epic poem Kambaramayanam by the 12th century poet, Kamban in Tamil and Ramacharitamanasa, a Hindi version of the Ramayana by the 16th century Saint Tulsidas. Other vernacular versions also exist in most major Indian languages. Contemporary versions of the Ramayana include Sri Ramayana Darshanam by Kuvempu in Kannada and Ramayana Kalpavrikshamu by Viswanatha Satyanarayana in Telugu, both of which have been awarded the Jnanpith Award. The epic has transformed across the diverse regions of India, which boast their own unique languages and cultural traditions.[11]

 

The essential tale of Rama has also spread across South East Asia, and evolved into unique renditions of the epic – incorporating local history, folktales, religious values as well as unique features from the languages and literary discourse. The Kakawin Ramayana of Java, Indonesia, the Ramakavaca of Bali, Hikayat Seri Rama of Malaysia, Maradia Lawana of the Philippines, Ramakien of Thailand (which calls him Phra Ram) are great works with many unique characteristics and differences in accounts and portrayals of the legend of Rama. The legends of Rama are witnessed in elaborate illustration at the Wat Phra Kaew temple in Bangkok. The national epic of Myanmar, Yama Zatdaw is essentially the Burmese Ramayana, where Rama is named Yama. In the Reamker of Cambodia, Rama is known as Preah Ream. In the Pra Lak Pra Lam of Laos, Buddha is regarded as an incarnation of Rama.

  

Avatara

The Ramayana speaks of how the Goddess Earth, Bhumidevi, came to the Lord Creator, Brahma begging to be rescued from evil kings who were plundering her resources and destroying life through bloody wars and evil conduct. The Devas also came to Brahma fearful of the rule of Ravana, the ten-headed rakshasa emperor of Lanka. Ravana had overpowered the Devas and now ruled the heavens, the earth and the netherworlds. Although a powerful and noble monarch, he was also arrogant, destructive and a patron of evil doers. He had boons that gave him immense strength and was invulnerable to all living and celestial beings, except man and animals.[12]

 

Brahma, Bhumidevi and the Devas worshipped Vishnu, the Preserver, for deliverance from Ravana's tyrannical rule. Vishnu promised to kill Ravana by incarnating as a man – the eldest son of Kosala's king Dasaratha.[12] His eternal consort, Lakshmi took birth as Sita and was found by king Janaka of Mithila while he was ploughing a field. Vishnu's eternal companion, the Ananta Sesha is said to have incarnated as Lakshmana to stay at his Lord's side on earth. Throughout his life, no one, except himself and a few select sages (among which are included Vasishta, Sharabhanga, Agastya and Vishwamitra) know of his destiny. Rama is continually revered by the many sages he encounters through his life, but only the most learned and exalted know of his true identity. At the end of the war between Rama and Ravana, just as Sita passes her Agni pariskha, Lord Brahma, Indra and the Devas, the celestial sages and Lord Shiva appear out of the sky. They affirm Sita's purity and ask him to end this terrible test. Thanking the Avatara for delivering the universe from the grips of evil, they reveal Rama's divine identity upon the culmination of his mission.[13]

  

Prince of Ayodhya

King Dasaratha performs a putrakameṣṭi yajña, a sacrifice to obtain offspring by pleasing the gods. He gives the sacred, sacrificial nectar to his three wives according to their seniority: Kousalya, Sumitra and Kaikeyi. On the night of the ninth day after Amavasya, under the asterism of Punarvasu and the cardinal sign of the Crab, Rama was born in the city of Ayodhya, which is the capital of the ancient kingdom of Kosala. The city and the area are located in the central region of the modern state of Uttar Pradesh in India. Rama was the prince of the Suryavamsha (Sun Dynasty) House of Ikshvaku, descendant of great monarchs like Ikshvaku, Raghu and Bhagiratha. He is the eldest brother to Bharata, son of Kaikeyi, and the twin sons of Sumitra, Lakshmana and Shatrughna. Rama is dark-complexioned, mainly bluish – a symbol of divinity.[14]

 

The Ramayana describes the relationship between the brothers as intensely loving and devotional, although Rama and Lakshmana share a special, inseparable bond, while Bharata is especially close to Shatrughna. The four brothers enjoy an undiscriminating love from Dasaratha and his three queens, but Dasaratha's main affections are affixed upon Rama. Rama and his brothers are trained by Rishi Vasishta in the Vedas, religion, philosophy and the sciences. They are described as taller than the tallest men of modern times, possessive of exceptional acumen and prowess in the military sciences and arts.[15]

  

Initiation of the Avatara

 

Rama breaking the bow, Raja Ravi Varma (1848–1906)Sage Vishwamitra takes the two princes, Rama and Lakshmana, to the Swayamvara ceremony for Sita. The challenge is to string the bow of Shiva, and shoot an arrow with it. This task is considered impossible for any ordinary king or living being, as this is the personal weapon of Shiva, more powerful, holy and of divine creation than conceivable. While attempting to string the bow, Rama breaks it into two. This feat of unbelievable strength, to have broken the bow of Shiva, spreads his fame across the worlds and seals his marriage to Sita.[16]

 

After Rama weds Sita and the entire royal family and the Ayodhya army begin their journey back, the great rishi Parashurama Bhargava appears before them, having descended from his mountainous hermitage. Parashurama is an extremely powerful rishi, responsible for killing all of the world's warriors and kings 21 times. He was the sixth Avatara of Vishnu, and finds it unbelievable that anybody could break the bow of Shiva. Considering himself to still be the most powerful warrior-rishi on earth, he brings with them the bow of Vishnu, and intends to challenge Rama to prove his strength by stringing it, and then fighting a battle with him to prove superiority.[17] Although the entire Ayodhya army is forestalled by his mystical power, Rama is himself angered. He respectfully bows to Parashurama, and within a twinkling of an eyelid snatches the bow of Vishnu, strings it, places an arrow and points it straight at the challenger's heart. Rama asks Parashurama what he will give as a target to the arrow in return for his life? At this point, Parashurama feels himself devoid of the tremendous mystical energy he possessed for so long. He realizes that Rama is Vishnu incarnate, his successor and definitely his superior. He accepts Rama's superiority, devotes his tapasya to him, pays homage to Rama and promises to return to his hermitage and leave the world of men.[18]

 

Rama then fired the arrow up into the sky with Vishnu's bow, performing a feat true to his Supreme, divine nature with his natural weapon. His overpowering of Parashurama and using the supreme weapon with incredible ease and perfection dazzle the spectators and his relatives, but no one save Parashurama and Vasishta associate this with his true identity. It is said that the Rama's arrow is still flying across space, across time and across all of the universe. The day it will return to earth, it is said, it will bring the end of the world. Others say that the flying arrow destroys all evil on earth to uphold dharma and righteousness.[18]

  

Another version

Another version of the story is, that Sage Vishvamitra along with Prince Rama and Lakshmana attended the Swayamvara of Princess Sita. To find the best match for his daughter Sita, King Janaka held a test in which the successful contestant was able to lift the bow of Lord Shiva and string it, would be able to wed Sita. However, none of the Kings were able to achieve this task, and disappointed, King Janaka pours out his dilemma and misery. Upon hearing this Lakshmana is enraged and offended that King Janaka did not offer Rama the same test. Upon the invitation of King Janaka, Lord Rama proceeded to the bow of Lord Shiva. Paying reverence to the bow, Rama was able to lift the bow, string it and in the same process broke the bow in two. This event sent a loud thundering sound throughout the whole planet and the noise reached the ears of Parasurama who was at that time meditating and knew that the sound made was the bow of Lord Shiva's being broken. When Parasurama arrived at the court of King Janaka, he confronted the prince and issued a challenge. This led to a confrontation between Lakshmana and Parusurama, who's rage was increasing at Lakshmana's impetuous backtalk. However, Lord Rama without any physical confrontation was able to pacify Parasurama. After calming down Parasurama realised that Rama was Lord Vishnu Incarnate and granted Lord Rama all the weapons he had obtained from his tapas.

  

Dharma of exile

King Dasaratha announces to Ayodhya that he plans to crown Rama, his eldest child the Yuvaraja (crown prince). While the news is welcomed by everyone in the kingdom, the mind of queen Kaikeyi is poisoned by her wicked maid-servant, Manthara. Kaikeyi, who is initially pleased for Rama, is made to fear for the safety and future of her son Bharata. Fearing that Rama would ignore or possibly victimize his youngest brother for the sake of power, Kaikeyi demands that Dasaratha banish Rama to a forest exile for fourteen years, and that Bharata be crowned in Rama's place. She had been granted two boons by the king when she had saved his life a long time ago, and the queen now used them to serve her purpose.[19] The king's court and the people are outraged at this turn of events. Dasaratha loved and cherished Rama dearly, and was in personal turmoil. Completely estranged now from his younger wife, he abhors the prospect of separation from Rama. But Rama realizes that the king must not break a solemn promise at any time, and neither should a son disobey his father's command. Sita joins her husband in exile despite his discouraging her, as it is her duty and out of love for Rama that she must be at his side at all times. His younger brother Lakshmana also immediately decides to join Rama rather than remain in the city.[20]

 

As he leaves for exile, the people of Ayodhya are deeply saddened and angered at Dasaratha and Kaikeyi. Dasaratha's heart is broken and he collapses and dies by the next day, unable to bear the agony of separation from Rama. Despite the reasoning of Vasishtha and the pleas of his brothers, Rama refuses to return. Although horrified at the news of his father's death, Rama finds it impossible that he should break his dead father's word. Rama does not bear any anger towards Kaikeyi, believing firmly in the power of destiny.[21] According to the explanation of the classic, this exile actually presents Rama the opportunity to confront Ravana and his evil empire.

  

Rama and Sita

 

A modern depiction of Sita and RamaRama and Sita are the protagonists in one of the most famous love stories of all time. Described as being deeply in love, Sita and Rama are theologically understood as avatars of Lakshmi and Vishnu respectively. When Rama is banished from the kingdom, he attempts to convince Sita not to join him in a potentially dangerous and certainly arduous existence in the jungle, but Sita rejects this. When Rama orders her in his capacity as husband, Sita rejects it, asserting that it was an essential duty of a wife to be at her husband's side come good or ill.[20] Rama in turn is assiduously protective and caring for Sita throughout the exile.

 

When Sita is kidnapped by Ravana, both Sita and Rama undergo great personal hardships during their separation. Sita protects her chastity assiduously, and survives over a year in captivity on the strength of her love and attention to religious values and duty. She is completely unfettered in her resolve despite Ravana's courting, cajoling and threats. Meanwhile Rama, not knowing who had kidnapped Sita or where was she taken, often succumbs to despair and tears, denouncing himself for failing to defend her and agonizing over her safety and pain. Sita knows that it is in Rama's destiny to fight to rescue her (she refuses to be rescued thus by Hanuman, who discovers her), but is deeply anxious for his safety and fearful of Ravana's power.

  

Agni pariksha

After Rama slays Ravana and wins the war, Sita wants to come before him in the state which over a year's imprisonment had reduced her to, Rama arranges for Sita to be bathed and given beautiful garments before they are re-united. But even as Sita comes before him in great excitement and happiness, Rama does not look at her, staring fixedly at the ground. He tells her that he had fought the war only to avenge the dishonour that Ravana had inflicted on Rama, and now Sita was free to go where she pleased. At this sudden turn of events, all the vanaras, rakshasas, Sugriva, Hanuman and Lakshmana are deeply shocked.[22]

  

Sita begs Lakshmana to build her a pyre upon which she could end her life, as she could not live without Rama. At this point, Lakshmana is angered at Rama for the first time in his life, but following Rama's nod, he builds a pyre for Sita. At the great shock and sorrow of the watchers, Sita walks into the flames. But to their greater shock and wonder, she is completely unharmed. Instead, she glows radiantly from the centre of the pyre. Immediately Rama runs to Sita and embraces her. He had never doubted her purity for a second, but, as he explains to a dazzled Sita, the people of the world would not have accepted or honoured her as a queen or a woman if she had not passed this Agni pariksha before the eyes of millions, where Agni would destroy the impure and sinful, but not touch the pure and innocent.[23]

 

Another version of this, used in Ramanand Sagar's RAMAYAN, was that Rama had known Sita was going to be abducted by Ravana ahead of time. So, he entrusted her to Agni Dev, or the God of Fire. Rama did this so that he, who in reality was Vishnu, could kill Ravana. Sita, in turn, left behind a "shadow", or twin-like version of herself behind. The "shadow" Sita had been abducted by Ravana. Therefore, the lila of Agni Pariksha was to retrieve the genuine Sita from the temporary care of Agni Dev. Rama explains this to Lakshmana before the so-called "Pariksha" is done. This version has also been written in the Ram Charit Manas.

  

Sita's banishment

In the Uttara Kanda, Rama banishes his wife Sita, even as she is pregnant, asking Lakshmana to deliver her safely to Rishi Valmiki's ashram. He does so when it is reported to him that some subjects of his in Ayodhya believe that Sita is unchaste due to her long captivity in Ravana's city. The Agni pariksha fails to convince these few critics, but Rama, by his understanding of the dharma of a king, decides to banish Sita. Rama adhered strictly to his duty both as a king and a husband. These conflicted when society thought that Sita was unfit to become queen. But Rama had to send away Sita since his duty of king came first. A legend by Rishi Agastya in the epic states that Vishnu in a previous age had been cursed by a rishi, whose wife had been killed by Vishnu for sheltering his enemies escaping from battle. The Rishi condemns Vishnu to be denied for a long age, the companionship of his soul mate, just as Vishnu, by an inadvertent display of anger, had deprived the rishi of his loving wife. Thus Rama, Vishnu's incarnation, must live the rest of his life without Sita.[24]

  

Maryada Purushottama

As a person, Rama personifies the characteristics of an ideal person (purushottama) who is to be emulated. He had within him all the desirable virtues that any individual would seek to aspire, and he fulfils all his moral obligations (maryada). Rama's purity and piety in his intentions and actions inspires affection and devotion for him from a variety of characters from different backgrounds. For example, he gave up his rightful claim to the throne, and agreed to go into exile for fourteen years, to fulfill the vow that his father had given to Kaikeyi, one of King Dashratha's wives. This is in spite of the fact that Kaikeyi's son, Bharat, begged him to return back to Ayodhya and said that he did not want to rule in place of Rama. But Rama considered his dharma as a son above that of his own birthright and his life's ambition. For such supreme sacrifices, and many other qualities, Shri Rama is considered a maryada purushottam. Some of his ideals are as follows:

 

1. At the time when it was normal for kings to have more than one wife, Rama gave ideal of having a single wife. After Sita was banished, he was doing penance with a gold statue of Sita. In Balakanda of Valmiki Ramayana it is written that Rama and Sita resided in each others heart.

 

2. Rama always followed his promise at any cost. In fact, he went to forest to make his father's promise to Kaikeyi true. There are many examples of Rama's promises which he kept. Most important are the promise to sages to save their lives from Rakshasas, getting back Sugreeva's kingdom, making Vibhishana the king of Lanka.

 

3. Excellent friend: Rama had very touching relations with his friends irrespective of their status. Some of his friends are Nishad-raj Guh, King of Nishaads (a caste whose profession was hunting the birds), Sugreeva (the Vanar king) and Vibhishana a Rakshasa.

  

Rama and non-violence

Rama is always shown with a bow (called Kodanda) on his shoulder. As per Valmiki Ramayana, Sita once enquired as to why her Lord, Rama always carried a bow with him. Sita was upset with Rama's promise to sages that he offer protection while they performed their sacrificial rituals and therefore petitioned Rama that 'We are in the forest and we should live life of sages so why wield this weapon?'. Sita then narrated a story about an ancient sage who became violent simply by having a weapon in his possession (in this case a sword). Rama smiled and promised to Sita that he would never attack anybody unless the other person provokes him to do so, a promise that he kept throughout his life. In fact he had always given two chances to his enemies Tataka, Maarich, Vali and even Ravana. He even offered a peace treaty to Ravana before starting the war. Angada took his peace message to Ravana which was declined.

  

Companions

Even as Rama is the ideal conception of manhood, he is often aided and complemented in different situations by the characteristics by those who accompany him. They serve Rama devotedly, at great personal risk and sacrifice.

  

Bharata and Lakshmana

Absent when Rama is exiled, upon his return Bharata is appalled to learn of the events. And even though Kaikeyi had done all this for his benefit, Bharata is angered at the suggestion that he should take Ayodhya's throne. Denouncing his mother, Bharata proclaims to the city that he would go to the forest to fetch Rama back, and would serve out his term of exile himself. Although initially resentful and suspicious, the people of Ayodhya hail Bharata's selfless nature and courageous act. Despite his fervent pleas to return, Rama asserts that he must stay in the forest to keep his father's word. He orders Bharata to perform his duty as king of Ayodhya, especially important after Dasaratha's death, and orders Shatrughna to support and serve him. Returning saddened to the city, Bharata refuses to wear the crown or sit on the throne. Instead, he places the slippers of Rama that he had taken back with him on the throne, and rules Ayodhya assiduously keeping Rama's beliefs and values in mind. When Rama finally returns, Bharata runs personally to welcome him back.

 

Bharata is hailed for his devotion to his elder brother and dharma, distinguished from Lakshmana as he is left on his own for fourteen years. But he unfailingly denies self-interest throughout this time, ruling the kingdom only in Rama's image.[25] Vasishtha proclaims that no one had better learnt dharma than Bharata,[26] and for this piety he forms an essential part of the conception of perfect manhood, of the Seventh Avatara of Vishnu. Shatrughna's role to Bharata is akin to that of Lakshmana to Rama. Believed to be one-quarter of Vishnu incarnated, or as the incarnation of his eternal companion, Ananta Sesha, Lakshmana is always at Rama's side.[27] Although unconstrained by Dasaratha's promise to Kaikeyi, Lakshmana resists Rama's arguments and accompanies him and Sita into the forest. During the years of exile, Lakshmana constantly serves Rama and Sita – building huts, standing guard and finding new routes. When Sita is kidnapped, Rama blazes with his divine power and in his immense rage, expresses the desire to destroy all creation. Lakshmana prays and pleads for Rama to calm himself, and despite the shock of the moment and the promise of travails to come, begin an arduous but systematic search for Sita. During times when the search is proving fruitless and Rama fears for Sita, and expresses despair in his grief and loneliness, Lakshmana encourages him, providing hope and solace.

 

When Rama in his despair fears that Sugriva has forgotten his promise to help him trace Sita, Lakshmana goes to Kishkindha where he reminds the complacent monarch of his promise to help. But Lakshmana also threatens Sugriva with destruction with his own divine, personal power, unable to tolerate the scene where Sugriva is enjoying material and sensual pleasures while Rama suffers alone. In the war, Lakshmana is uniquely responsible for slaying Indrajit, the invincible son of Ravana who had humiliated Indra and the Devas, and outwitted the brothers and the Vanaras on several occasions. Rishi Agastya later points out that this victory was the turning point of the conflict. Rama is often overcome with emotion and deep affection for Lakshmana, acknowledging how important and crucial Lakshmana's love and support was for him. He also trusts Lakshmana to carry out difficult orders – Lakshmana was asked to take Sita to the ashrama of Valmiki, where she was to spend her exile. Lakshmana's deep love for Rama, his unconditional service and sacrifice, as well as qualities of practical judgment and clear-headedness make him Rama's superior in certain situations and perspectives. Lakshmana symbolizes a man's duty to his family, brothers and friends, and forms an essential part of the conception of ideal manhood, that Rama primarily embodies.

  

Jatayu, Hanuman and Vibheeshana

When Rama and Lakshmana begin the desperate search to discover where Sita had been taken. After traversing a distance in many directions, they come across the magical eagle Jatayu, who is dying. They discover from Jatayu that a rakshasa was flying away with a crying, struggling Sita towards the south. Jatayu had flown to the rescue of Sita, but owing to his age and the rakshasa's power, had been defeated. With this, Jatayu dies in Rama's arms. Rama is overcome with love and affection for the bird which sacrificed its own life for Sita, and the rage of his death returns to him in the climactic battle with Ravana.

 

Rama's only allies in the struggle to find Sita are the Vanaras of Kishkindha. Finding a terrified Sugriva being hunted by his own brother, king Vali, Rama promises to kill Vali and free Sugriva of the terror and the unjust charge of plotting to murder Vali. The two swear everlasting friendship over sacred fire. Rama's natural piety and compassion, his sense of justice and duty, as well as his courage despite great personal suffering after Sita's kidnapping inspire devotion from the Vanaras and Sugriva, but especially Hanuman, Sugriva's minister. Devoted to Rama, Hanuman exerts himself greatly over the search for Sita. He is the first to discover that Sita was taken to Lanka, and volunteers to use his divine gifts in a dangerous reconnaissance of Lanka, where he is to verify Sita's presence. Hanuman hands Rama's ring to Sita, as a mark of Rama's love and his imminent intention of rescuing her. Though captured, he candidly delivers Rama's message to Ravana to immediately release Sita, and when his tail is burned, he flees and sets Lanka on fire. When Lakshmana is struck down and near death and Rama overcome with love and concern for his brother, Hanuman flies to the Himalayas on the urgent mission to fetch the sanjeevani medicinal herbs, bringing the entire mountain to Lanka so that no time is lost in saving Lakshmana.[28] The Vanaras fight the rakshasas, completely devoted to Rama's cause. They angrily dismiss Ravana's efforts to create divisions by suggesting that Rama considered them, monkeys, as mere animals. At the end of the war, Rama worships Brahma, who restores life to the millions of fallen Vanaras.[29]

 

Before the onset of war, rakshasa prince Vibheeshana, Ravana's youngest brother comes to join Rama. Although he loves his brother and Lanka, he fails in repeated efforts to make Ravana follow religious values and return Sita. Vibheeshana believes that Ravana's arrogance and callousness will cause the destruction of Lanka, which is a gross violation of a king's duty, and that Ravana's actions have only propagated evil. Vibheeshana refuses to defend the evil of Ravana's ways and inspired by Rama's compassion and piety, leaves Lanka to join the Vanara Army.[30] His knowledge of rakshasa ways and Ravana's mind help Rama and the Vanaras overcome black magic and mystical weapons. At the end of the war, Rama crowns Vibheeshana as the king of Lanka. Vibheeshana, and to a greater extent Hanuman, embody the perfect devotee in the wider conception of perfect manhood.

  

Rama in war

 

The epic story of Ramayana was adopted by several cultures across Asia. Shown here is a Thai historic artwork depicting the battle which took place between Rama and Ravana.When Rama is sixteen years old, he and his brother Lakshmana are taken by Vishwamitra to the forests, with the purpose of killing rakshasas who are wrecking the tapasya and sacrifices of brahmins. Rama and Lakshmana are taught the advanced military arts and given the knowledge of all celestial weapons by Vishwamitra. Rama proceeds to slay Thatakhi, a cursed demoness. When asked to slay the yaksha demon, Rama demurs, considering it sinful to kill a woman. But Vishwamitra explains that evil has no gender. The killing of Taraka liberates the yaksha soul who was cursed for a sin, and had to adopt a rakshasi's body. It restores the purity of the sacrifices of the brahmins who live nearby, and protects the animals who live in the forest, and travelers. The main purpose of Vishwamitra's exursion is to conduct his yagna without interruption from two evil demons, Maricha and Subahu. Rama and Lakshmana guard the sacrifice, and when the two demons appear, Rama shoots an arrow that carries Maricha across the lands and into the ocean, but does not kill him. Rama and his brother then proceed to kill Subahu and accompanying demons. Rama explains to Lakshmana that leaving Maricha alive was an act of compassion, but the others did not heed the point and chose to attack.[31] During the forest exile, sages plead for protection and help against evil rakshasas who spoil their sacrifices and religious activities and terrorize them. Many rakshasas had even killed and eaten sages and innocent people. At Janasthana, Rama uses his exceptional prowess to single-handedly kill over fourteen thousand demon hordes led by the powerful Khara, who is a cousin of Ravana.

  

Sagara

 

Raja Ravi Varma Painting – 'Rama Conquers Varuna'Faced with the dilemma of how to cross the ocean, Rama performs a penance tapasya, fasting and meditating in perfect dhyana for three days and three nights to sagara, the Lord of Oceans. The ocean god does not respond out of arrogance , and Rama on the fourth morning,pointed the brahmastra towards the ocean . The Vanaras are dazzled and fearful at witnessing the enraged Rama demolish the oceans, and Lakshmana prays to calm Rama's mind. Just as Rama invokes the brahmastra, considered the most powerful weapon capable of destroying all creation, Saagara arises out of the oceans. He bows to Rama, and begs for pardon. Since lord Rama had to use the weapon , he suggests Rama re-direct the weapon at a demonic race that lives in the heart of the ocean. Rama's arrows destroys the demons, and establishes a purer, liberated environment there. Saagara promises that he would keep the oceans still for all of Rama's army to pass, and Nala constructs a bridge (Rama's Bridge) across to Lanka. Rama justifies his angry assault on the oceans as he followed the correct process of petitioning and worshipping Saagara, but obtaining the result by force for the greater good.[32]

 

In another version of the story, Lord Rama redirected his missile to the barren Island, and as a result huge volcanic eruption resulted. This volcano is the one which is found till today at the southern part of Indian peninsula .

  

Facing Ravana

 

Ravana, Hindu Demon King of LankaRama asserts his dedication to dharma when he undertakes to offer Ravana a final chance to make peace, despite his heinous actions and patronage of evil, by immediately returning Sita and apologizing to both Rama and Sita, but Ravana refuses. In the war, Rama slays the most powerful rakshasa commanders, including Prahasta, Atikaya and with Ravana's brother, Kumbhakarna along with hundreds of thousands of rakshasa soldiers. He outfights Ravana in their first battle, destroying his chariot and weapons, and severely injuring him, but due to this, he allows him to live and return to fight another day. But as a human being, Rama also proves vulnerable on occasion to his enemies. He is put to a deep sleep with Lakshmana by the nagapoosas of Indrajit, but they recover when Hanuman obtains the magical medicine according to Vibheesana's advice.

 

In the grand finale of the battle, Rama engages Ravana, who through the devastation of losing his sons, his brothers and friends and millions of his warriors, arouses his awesome and magical powers and makes full use of the boons of Siva and Brahma, and the magical knowledge of warfare possessed by the greatest of rakshasas. Rama and Ravana compete fiercely, inflicting severe injuries on one another with the most powerful weapons that could destroy the universe. After a long and arduous battle, Rama successfully decapitates Ravana's central head, but an ugly head, symbolic of all of Ravana's evil powers arises in its place. After another long battle, Rama decapitates it, only to find another growing in its place. This cycle continues, and as darkness approaches, Ravana's magical powers increase in force. Vibheeshana, seeing this then tells Rama something vital. Ravana had obtained amrita, the nectar of immortality, from the gods. Though he could not consume it, he nevertheless stored a vessel of it in his stomach. This amrit was causing his heads to regenerate as soon as they were cut off. Upon the advice of Agastya, Rama worships Lord Aditya, the Sun, with the famous Aditya Hridayam prayer and then invokes the most powerful weapon, the Brahmastra. Rama fires the great arrow that enters Ravana's chest/stomach and destroys the store of amrit, killing him finally.[33] Following Ravana's death, Rama is immediately compassionate. After investing Vibheeshana as the next king of Lanka, he asks the new king and the surviving rakshasas to properly cremate their dead king, who he acknowledges was a great being worthy of respect and admiration, despite his patronage of evil.[34]

  

Rama Rajya

The end of the war coincides with the end of Rama's tenure of exile. Flying home on the Pushpaka Vimana, Rama returns to a joyous Ayodhya. His mothers, brothers and the people joyously welcome him. Kaikeyi is repentant of her deeds, and Rama forgives her. The next day, Rama is invested as the King of Ayodhya, and Emperor of the World. Although he first asks Lakshmana to become the yuvaraja, upon the advice of Lakshmana he invests the position to Bharata, who has had fourteen years of experience as the ruler of Ayodhya. Rama performs the holy Ashwamedha sacrifice, purifying and establishing religion across earth.[35]

 

Beyond the Ramayana, the eleven thousand years of Rama's rule over the earth represent to millions of modern Indians a time and age when God as a man ruled the world. There was perfect justice and freedom, peace and prosperity. There are no natural disasters, diseases, ailments or ill-fortune of any nature for any living being. There are no sins committed in the world by any of his people. Always attentive and accessible to his people, Rama is worshipped and hailed by all – the very symbol of moksha, the ultimate goal and destination of all life, and the best example of perfect character and human conduct, inspiring human beings for countless succeeding ages.

 

Rama like other Indian kings went undercover every night to hear the pleas of his subjects and have a common man's perspective of his rule. During Rama's tenure as King, the people apparently had no locks on their doors as they feared no burglaries or other such misfortunes.

  

Rama and the world

 

Deities of Sri Sri Sita (far right), Rama (center), Lakshmana (far left) and Hanuman (below seated) at Bhaktivedanta Manor, a temple in Watford EnglandBe it as a manifestation of God or simply as a legendary hero of myths and folktales, Rama is an immensely revered and inspirational figure to people across the Indian subcontinent and South East Asia, as well as increasingly across Western civilization, where the Hindu epics and values are gaining recognition and popularity. In Jainism, Rama is enumerated among the nine white Balas. He is revered in Sikhism,(in the Guru Granth Sahib)[citation needed]

 

Rama is a great hero to the adherents of Agama Hindu Dharma and to the Muslims who practice Abangan, a syncretic form of Islam and Hinduism, in Indonesia. He is revered by the people of Thailand, Malaysia, Myanmar, Cambodia and Vietnam, who otherwise adhere to different forms of Buddhism, Islam and Hinduism. The Rama Leela is performed across South East Asia in numerous local languages and the story has been the subject of art, architecture, music, folk dance and sculpture. The ancient city of Ayutthaya stands in Thailand, as the tribute of an ancient Thai kingdom to the great legend. Many ancient and medieval era kings of South East Asia have adopted Rama as their name.

 

A Buddhist version of the tale is found in the Jataka stories, in the Dasharatha Jataka (Jataka Atthakatha 461) in the Pali vernacular. Here Rama is represented as a former life of the Buddha as a Bodhisatva and supreme Dharma King of great wisdom. In the Buddhist tale, he is the king of Varanasi and not Ayodhya, which is traditionally the capital of Kosala.

  

Festivals of Lord Rama

Rama's day and time of birth, as well as marriage to Sita are celebrated by Hindus across the world as Rama Navami. It falls on the ninth day of a Hindu lunar year, or Chaitra Masa Suklapaksha Navami. This day is observed as the marriage day of Rama and Sita as well as the birthday of Rama. People normally perform Kalyanotsavam (marriage celebration) for small statues of Rama and Sita in their houses and at the end of the day the idols are taken in a procession on the streets. This day also marks the end of nine day utsavam called Vasanthothsavam (Festival of Spring), that starts with Ugadi. Some highlights of this day are:

 

Kalyanam (Ceremonial wedding performed by temple priests) at Bhadrachalam on the banks of the river Godavari in Khammam district of Andhra Pradesh.

Panakam, a sweet drink prepared on this day with jaggery and pepper.

Procession of idols in the evening that is accompanied with play of water and colours.

For the occasion, Hindus are supposed to fast (or restrict themselves to a specific diet).

Temples are decorated and readings of the Ramayana take place. Along with Rama, people also pray to Sita, Lakshmana and Hanumana.

The occasion of victory over Ravana and the rakshasas is celebrated as the 10-day Vijayadashami, also known as Dussehra. The Ram Leela is publicly performed in many villages, towns and cities in India. Rama's return to Ayodhya and his coronation are celebrated as Diwali, also known as the Festival of Lights. The latter two are the most important and popular festivals in India and for Hindus across the world. In Malaysia, Diwali is known as Hari Deepavali, and is celebrated during the seventh month of the Hindu solar calendar. It is a federal public holiday. In many respects it resembles the traditions followed in the Indian subcontinent. In Nepal, Diwali is known as Tihar and celebrated during the October/November period. Here, though the festival is celebrated for five days, the traditions vary from those followed in India. On the first day, cows are worshipped and given offerings. On the second day, dogs are revered and offered special food. On the third day, celebrations follow the same pattern as in India, with lights and lamps and much social activity. On the fourth day Yama, the Lord of Death, is worshipped and appeased. On the fifth and final day, brothers sisters meet and exchange pleasantries. In Trinidad and Tobago, Diwali is marked as a special occasion and celebrated with a lot of fanfare. It is observed as a national holiday in this part of the world and some ministers of the Government also take part in the celebrations publicly.

  

Inspiration

Mohandas Karamchand Gandhi, the Indian spiritual and political leader was deeply inspired by Rama's strict adherence of satya (truth) and dharma despite hardship and personal travails. Gandhi was encouraged by Rama's example when he faced personal crises and crucial difficulties. A chapter in his autobiography is titled the same: Nirbal ke Bal Ram (Rama is the strength for the weak). On religious occasions, Hindus often chant the name of Rama to express their devotion to God and invoke the holy. Ram Naam Japo (Chant the name of Rama) is a popular bhajan, devotional song and a meditative mantra. In the ceremony of cremating the dead, Hindus often chant Ram Nam Satya Hai (Rama's name is Truth).

 

from wikipedia

See: www.whitman.edu/theatre/theatretour/glossary/glossary.htm#v

Lengths 16.4 mm (left, about 17.5 mm before posterior damaged) & 17.5 mm. W. Anglesey, Wales. March 2014. Similar length shells, but right one narrower with larger keyhole aperture .

FULL SPECIES DESCRIPTION below.

Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/.

PDF available at www.researchgate.net/publication/270566202_Diodora_graeca...

 

Key identification features

·Diodora graeca

·Limpet with ‘keyhole’ aperture in front of forward tilted apex, one third of way from anterior edge of shell.

·Maximum size: height 10mm, length 25mm.

·Littoral and sublittoral on most rocky coasts of Britain & Ireland, but not North Sea or N.E. Irish Sea.

 

Diodora graeca (Linnaeus, 1758)

 

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=139951

Synonyms: Patella graeca Linnaeus, 1758; Fissurella graeca (Linnaeus, 1758) [in Jeffreys]; Fissurella reticulata (da Costa, 1778); Diodora apertura (Montagu, 1803); [F. reticulata, Donovan in Forbes & Hanley].

Meaning of scientific name: Diodora = woman's name, graeca = Greek.

Vernacular: Keyhole limpet (English); Brenigen bendoll (Welsh); sleutelgathoren (Dutch); fissurelle (French).

 

*GLOSSARY below.

 

Shell Description

Height of cone up to 10mm. Those living intertidally usually smaller. Conical, usually straight or concave anterior profile; straight or convex posterior profile 1Dg flic.kr/p/neENkH . Apex about a third of way from anterior, with slit aperture immediately in front. Slit varies in size on shells of same size 2Dg flic.kr/p/neEJnk ; rounded at anterior and posterior ends, slightly constricted at mid point giving a keyhole or figure-8 outline. Very small young have spiral protoconch 23Dg flic.kr/p/tkSJWS & 24Dg flic.kr/p/tCymA4 , but soon lost through erosion/ expansion of apical aperture. Rim often raised at mid point, but erosion may remove this and the constriction 3Dg flic.kr/p/neELAa . Slit also constricted at interior end by an encircling shelf 4Dg flic.kr/p/nvSugi . Sculpture of upturned, concentric, annual growth rings; about thirteen on 17.5mm long specimen; number is underestimate of age as earliest rings destroyed by apical aperture enlarging with growth of shell. Up to fifty radiating flattish-topped ridges with narrow intervening grooves cut across growth rings, producing a pan-tile roof effect 2Dg flic.kr/p/neEJnk . Main aperture up to 25mm long, 15mm broad. Elongated ellipse, posterior wider than anterior 5Dg flic.kr/p/neEV7s . Ratio width:length varies 2Dg flic.kr/p/neEJnk . Edge crenulated by ends of ridges. Lateral edge of aperture arched up from horizontal; not moulded to substrate as usually rests on foot 6Dg flic.kr/p/neEUeY . Interior of shell coated with white porcellanous nacre, thickened into pronounced rim around apical aperture 4Dg flic.kr/p/nvSugi , and with short radial grooves at edge of main aperture aligned with ridges on dorsal surface. Larval operculum lost at metaphorphosis. Ground colour of shell exterior almost lustreless whitish and/or tan-white with, often incomplete, radiating bands of grey, rusty-, greenish- or dark-brown 2Dg flic.kr/p/neEJnk. Bands faintly visible on interior 5Dg flic.kr/p/neEV7s . Live shells often coated with detritus and epizooic growths 7Dg flic.kr/p/neEU61 . Colours fade on dead shells 1Dg flic.kr/p/neENkH . Periostracum imperceptible.

 

Body description

Flesh cream, pale yellow 26DG flic.kr/p/sFCbuM , yellow 8Dg flic.kr/p/neEFmv , orange 9Dg flic.kr/p/nxWg86 or red, often spotted with a darker shade (except tentacles, part of snout, and body above epipodial tentacles 10Dg flic.kr/p/nwapep . Snout large with thick lips 10Dg flic.kr/p/nwapep , can project downwards or forwards 8Dg flic.kr/p/neEFmv . Cephalic tentacles long, colour as body, or paler, without darker spots. Small black eye on very small peduncle at base of each cephalic tentacle 8Dg flic.kr/p/neEFmv . Elaborate mantle has three folds: 1. outer fold reaches aperture rim 19Dg www.flickr.com/gp/56388191@N08/N3b4Ls , in contact with inner surface of shell, produces calcareous matter to line interior and enable growth at edge of aperture, 2. middle fold extends as nodular glandular tentacles (possibly secrete repugnatory matter) protruding at ends of radiating shell ridges 9Dg www.flickr.com/gp/56388191@N08/UBWZ7y & 11Dg www.flickr.com/gp/56388191@N08/m40J10 , 3. greatly enlarged inner fold forms curtain, often completely shielding head and foot 12Dg www.flickr.com/gp/56388191@N08/Xy2r6m but they may protrude when in motion 8Dg flic.kr/p/neEFmv , and at times mantle is drawn within shell 13Dg www.flickr.com/gp/56388191@N08/N7x2x9 . Mantle also extends from apical slit as brown exhalent siphon accompanied by rounded, dark brown, densely lobular, anterior and posterior lappets; on some adults these features are yellowish white with little pigment 14Dg www.flickr.com/gp/56388191@N08/4MV7Y7; and juveniles usually lack much pigment 25Dg flic.kr/p/tA81Fw & 26Dg flic.kr/p/sFCbuM . Lobules may produce repugnatory substances, and, as the lappet bases are neatly recessed in the rounded ends of the “keyhole”, very probably substances to dissolve/resorb shell as the apical slit aperture is enlarged. Sides of slit are constricted and higher perhaps because not touched by lappets; lesser enlargement there may be caused by secretions from narrower erect siphon. Encircling nacreous shelf around base of apical slit may be because nacre (aragonite) is more resistant than calcite of outer shell or is deposited faster than resorbed, or because underside of lappets do not reach down so far. Foot, sole a broad ellipse 15Dg www.flickr.com/gp/56388191@N08/1sqP6j , sometimes anterior indented centrally 16Dg www.flickr.com/gp/56388191@N08/5381v1 . Coloured as mantle or paler, except sole which lacks darker spots. When emersed from water, usually much of foot and mantle remain exposed 9Dg www.flickr.com/gp/56388191@N08/UBWZ7y . Defence may rely on repugnatorial glands in mantle skirt and sides of foot, though latter may be antiseptic rather than repugnatorial (Fretter & Graham 1994). Junction line of foot with upper body has row on each side of about 30 touch-sensitive epipodial tentacles, usually alternating large / small 13Dg www.flickr.com/gp/56388191@N08/N7x2x9 . Enlarged epipodial tentacle at base of right eye peduncle has been mistaken for penis, but D. graeca has none (enlarged epipodial tentacle on both sexes and also by left eye 17Dg www.flickr.com/gp/56388191@N08/227SzX ). Strong whitish horseshoe-shape shell-muscle connects animal to shell 17Dg www.flickr.com/gp/56388191@N08/227SzX .

 

Internal anatomy visible with simple dissection

When the shell is removed, the whole mantle is exposed. The central part is translucent except for the brown apical siphon, dark-brown siphon-lappets and a broad dark-edged collar round the siphon. Several features can be seen through the mantle 18Dg www.flickr.com/gp/56388191@N08/6369U1 , but are more easily viewed if it is removed 19Dg www.flickr.com/gp/56388191@N08/N3b4Ls . The peripheral mantle skirt has dark scallop marks where it fitted the crenate shell-edge 19Dg www.flickr.com/gp/56388191@N08/N3b4Ls . In the nuchal cavity above the head, and below the apical siphon, are two ctenidia, symmetrically arranged with the central anus and kidney opening at their base 20Dg www.flickr.com/gp/56388191@N08/09Yquk . Behind the anus are the kidney, digestive gland and gonad (orange and granular with ova in female 19Dg www.flickr.com/gp/56388191@N08/N3b4Ls , whitish in male 18Dg www.flickr.com/gp/56388191@N08/6369U1 ). Next to the left ctenidum is the style sac region of stomach. Encircling the viscera, and separating them from the mantle skirt, is the white horseshoe-shaped shell-muscle (severed to remove previously anaeshetised and killed animal from shell).

 

Key identification features

·Diodora graeca

·Limpet with ‘keyhole’ aperture in front of forward tilted apex, one third of way from anterior edge of shell.

·Maximum size: height 10mm, length 25mm.

·Littoral and sublittoral on most rocky coasts of Britain & Ireland, but not North Sea or N.E. Irish Sea.

 

Similar species

·Puncturella noachina

·Limpet with narrow slit aperture in front of backward curving, nearly central, apex.

·Slit partly blocked internally by septum.

·Maximum size: height 4mm, length 7mm.

·On stones from hard bottoms at 20m to 150m deep in Scottish waters, south to Yorkshire. (Littoral in higher latitudes).

 

Habits and ecology

Sublittorally to 250m on hard substrate where sponges grow, including oyster beds, dead shells and rocks. As apical aperture and exposure of foot reduce resistance to dessication, littoral specimens restricted to permanently moist niches near LWS, such as underside of large stable rocks that are not embedded in sediment. Prospers where moderate amount of suspended matter in water if able to crawl on rock to avoid smothering; shell often coated in epizooic growths with adhering detritus 21Dg www.flickr.com/gp/56388191@N08/1VRQ30 . Lives in fully marine salinity down to 21 ppt.

Water enters mantle cavity from front and both sides, washes over pair of respiratory ctenidia and central anus 20Dg www.flickr.com/gp/56388191@N08/09Yquk , and exits with faeces through apical siphon. Detritus and faecal matter too dense to be swept upwards are cleared via main aperture by periodic forcible contraction of shell-muscle to clamp down shell like a sink-plunger. Experimentally blocking apical cavity of American sp. Diodora aspera produced no observable harm; flow became inhalent at sides, exhalent at anterior (Voltzow & Collins in Wylan). But passage of faeces over ctenidia makes sanitation problems more likely in the long term.

Clings to same spot on rock for long periods and returns after feeding expeditions. Foot adheres strongly, but not as well as patellid limpets, so can not survive in such wave-exposed positions as they can. Large mantle curtain and parts of head and foot exposed as it moves 22Dg www.flickr.com/gp/56388191@N08/xHk8xe .

Feeds on sponges, especially Halichondriahttp://www.habitas.org.uk/marinelife/sponge_guide/sponges.asp?item=C4840 and Hymeniacidon www.habitas.org.uk/marinelife/sponge_guide/sponges.asp?it... , and perhaps some detritus. Flesh colours match colours of sponge. A string of mucus with food particles in it is moved through the stomach by the rotary action of a gelatinous rod, the ‘crystalline style’. Style sac part of the stomach can be seen next to the left ctenidium. As faeces are directed away from ctenidia to apical siphon there is less need for compaction of faeces to avoid contamination, so intestine much shorter and less looped than in most patellids 19Dg www.flickr.com/gp/56388191@N08/N3b4Ls . Comminuted/semi liquid faeces are blown out of siphon in an easily dispersed cloud that does not settle on the shell (P.M. Crowther, unpublished video.shown on British Marine Mollusca Facebook Group on 17 June 2020).

Breeds December-May in Plymouth. External fertilization by male, presumably proximate, as female spawns. Sperm emerges from kidney opening adjoining anus 20Dg www.flickr.com/gp/56388191@N08/09Yquk , so probably exits mantle cavity through apical siphon above . Within ovary, egg capsules have reticulated orange shells 19Dg www.flickr.com/gp/56388191@N08/N3b4Ls . Spawn exits anterior of mantle cavity as continuous stream and spread by foot on underside of a rock where ova swell into continuous, yellow, adhesive, gelatinous sheet several cm across, that soon hardens. Ova arranged one deep, each touching its neighbours. Trochophore and veliger stages passed in ova. Young emerge as crawlers with spiral protoconch of one & a half whorls with no apical opening. As it grows, a slit appears in anterior edge of mantle with associated slit in margin of developing cone (enlarged body-whorl). Later, mantle slit closes at margin, leaving the earlier slit in mantle and shell as a hole on anterior face of shell. Further differential growth results in hole migrating to apex of shell in adult, and loss of protoconch by erosion and hole growth.

Distribution and status

Faroe Islands to Canary Islands, eastern Mediterranean and Aegean. GBIF map www.gbif.org/species/2293564 . On hard substrate around Ireland, Isle of Man, and south and west coasts of Britain from Kent to Caithness, Orkney and Shetland. Apparently absent from North Sea (beware of washed up fossil Diodora) and N.E. coast of Irish Sea. U.K. map NBN species.nbnatlas.org/species/NBNSYS0000174957

 

Links and references

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1849), London, van Voorst. (As Fissurella reticulata; Free pdf at archive.org/details/historyofbritish02forb Use slide at base of page to select pp.467-472.)

 

Fretter, V. and Graham, A. 1962 & 1994 ed. British prosobranch molluscs. London, Ray Society.

 

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London.

 

Jeffreys, J.G. 1862-69. British conchology. vol. 3 (1865). London, van Voorst. (As Fissurella graeca; Free pdf at archive.org/details/britishconcholog03jeffr . Use slide at base of page to select pp. 265-268 .)

 

Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. Sponges of Britain and Ireland

www.habitas.org.uk/marinelife/sponge_guide/sponges.asp?it...

 

Voltzow, J. and Collins, R. 1995. Flow through mantle cavities revisited: was sanitation the key to fissurellid evolution? Invertebrate Biology 114, number 2: 145-150. In Wylan B.J. 2014. Animal Diversity Web animaldiversity.ummz.umich.edu/accounts/Diodora_aspera/

 

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=139951

 

Glossary

aperture = mouth of gastropod shell; outlet for head and foot.

cephalic = (adj.) of or on the head.

  

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

 

ELWS = extreme low water spring tide (usually near March and September equinoxes).

 

epipodial = (adj.) of the epipodium (collar or circlet running round sides of foot of some gastropods).

 

epipodium = collar or circlet running round sides of foot of some gastropods, often bearing epipodial tentacles.

 

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

 

MLWS = mean low water spring tide level (mean level reached by lowest low tides for a few days every fortnight; Laminaria or Coralline zone on rocky coasts).

 

operculum = plate of horny conchiolin, rarely calcareous, used to close shell aperture.

periostracum = thin horny layer of chitinous material often coating shells.

repugnatorial = serving to repel enemies.

trochophore = spherical or pear-shaped larva that swims with aid of girdle of cilia. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for patellid limpets, most Trochidae and Tricolia pullus.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

Shell a low conoid; ground colour whitish tinted pale-pink; threadlike radiating striae obscure/absent on this specimen.

 

Full SPECIES DESCRIPTION BELOW (Revised 2020)

Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/

Revised, 2020, PDF version at www.researchgate.net/profile/Ian_Smith19/research

 

Tectura virginea (O.F. Müller, 1776)

 

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=153552

Synonyms: Patella virginea O.F. Müller, 1776, 1776; Patelloida virginea (O.F. Müller, 1776); Acmaea virginea (O.F. Müller, 1776); Acmaea virginica in Yonge & Thompson, 1976;

Vernacular names: White tortoiseshell limpet; Pink-rayed limpet (English); Brenigen wen (Welsh); Stribet albueskael (Danish); schoteltje (Dutch); Jungfräuliche Napfschnecke (German); jomfrusnegl (Norwegian); jungfruskålsnäcka (Swedish);

 

GLOSSARY below.

 

Shell Description

Up to 12 mm long. Often thin and fragile. Usually a low conoid 1Tv flic.kr/p/tg3YWR , occasionally high. Excentric apex tilted forwards, usually 18% to 30% of shell-length from anterior; sometimes more central on sublittoral specimens. Base oval, sometimes widest at posterior 2Tv flic.kr/p/sYsjKh . Anterior profile slightly concave; posterior profile slightly convex; often distinct changes in slope 3Tv flic.kr/p/tg3WuB . Sculpture of slight threadlike radiating striae 2Tv flic.kr/p/sYsjKh , often indistinct or absent 1Tv flic.kr/p/tg3YWR , and numerous fine concentric growth lines, sometimes emphasised by algal growths 4Tv flic.kr/p/sYAote ; smooth surface unless coated with Lithothamnion 5Tv flic.kr/p/sj3eSy Young shells are translucent with a tiny, white, semi-spiral, apical protoconch 40Tv flic.kr/p/2jQTrLN discernible until the shell is about 1.5mm long, after which it is usually eroded. External ground colour of live shell whitish, often tinted pale-pink 1Tv flic.kr/p/tg3YWR or pale-blue 3Tv flic.kr/p/tg3WuB . Central early growth usually patterned with tessellating chains of light brown, sometimes with bright blue spot in each link 3Tv flic.kr/p/tg3WuB ; frequently worn off older shells 2Tv flic.kr/p/sYsjKh . On later peripheral growth 16-20 flaring, radiating, pink to liver-coloured rays usually replace chains 6Tv flic.kr/p/sj3bKb . Colours fade rapidly after death 2Tv flic.kr/p/sYsjKh . Internally, shell often translucent whitish, with some exterior markings showing through 7Tv flic.kr/p/tg6zWx ; sometimes red-brown, complete or partial V with point near vertex and arms to posterior 2Tv flic.kr/p/sYsjKh .

Older shells often lined with thin porcellaneous layer that reduces translucency and conceals exterior markings. In fresh shells, often distinct U-shape shell-muscle scar, broad peripheral whitish pallial band, and central white viscera patch 8Tv flic.kr/p/sjeoa3 . Fragile shells soon beach-worn and faded after death; older shells and those reinforced by coating of Lithothamnion (opaque chalky white when dead) survive best and most frequently found on strand-line 9Tv flic.kr/p/tghKfR .

 

Body description

Main colour of flesh white, yellowish or pinkish. Head has short stout snout with large mouth. When not feeding, outer lip forms large prominent ridge with loose lateral flaps around anterior and sides of mouth10Tv flic.kr/p/sjq6gF . When feeding, outer lip expands into translucent oral veil on substrate 11Tv flic.kr/p/tfYATC & 12Tv flic.kr/p/tdUW2w . Long, slender, unpigmented cephalic tentacles, wrinkled when not fully extended 11Tv flic.kr/p/tfYATC . Black eye on dorsum of base of each tentacle, but difficult to view when live as not extended beyond shell and, when viewed ventrally, usually obscured by tentacle 13Tv flic.kr/p/tfYzmE ; also eye often unpigmented so obscure. Red buccal mass shows pink through parts of head 14Tv flic.kr/p/tdUUSs . Mantle-skirt white 12Tv flic.kr/p/tdUW2w , yellowish 13Tv flic.kr/p/tfYzmE , or blue-green 14Tv flic.kr/p/tdUUSs with reddish bands on periphery that produce corresponding rays of shell 14Tv flic.kr/p/tdUUSs . Mantle cavity consists of nuchal cavity over head, and groove (lacking pallial gills) around periphery of foot 14Tv flic.kr/p/tdUUSs . Substantial single ctenidium with short lamellae, colour similar to mantle, attached inside left of nuchal cavity and extends across to right 15Tv flic.kr/p/sYFKbL . Unlike in most gastropods, ctenidium not attached to cavity roof or floor, other than at its base, and lamellae lack internal skeleton, so able to contract to 50% of size and withdraw completely into nuchal cavity above head 14Tv flic.kr/p/tdUUSs ; but tip sometimes visible over right “shoulder” 13Tv flic.kr/p/tfYzmE . When animal moving, ctenidium often fully extended but hidden between shell and extended foot/outer lip 12Tv flic.kr/p/tdUW2w , except occasionally tip protrudes beyond shell. Clear view of ctenidium possible when inverted animal stretches to right itself 16Tv flic.kr/p/sYH1Lo . Periphery of mantle has many large white 'repugnatorial glands' set back from mantle edge and connected to it by narrow white necks 14Tv flic.kr/p/tdUUSs . Outer edge of mantle has many small, unobtrusive, translucent, cilia-bearing sensory processes 17Tv flic.kr/p/sYPNR6 . U of white muscle bundles 13Tv flic.kr/p/tfYzmE (blood vessels pass through the gaps), may be tinted as mantle , attaches body/foot to shell 18Tv flic.kr/p/tg1VSW . Foot yellow 13Tv flic.kr/p/tfYzmE or white 11Tv flic.kr/p/tfYATC ; sole oval, sometimes shows viscera 19Tv flic.kr/p/sjgCkU . When crawling, usually only long whitish cephalic tentacles 6Tv flic.kr/p/sj3bKb , and occasionally tip of ctenidium, visible dorsally; and whitish sides of foot and head visible laterally 11Tv flic.kr/p/tfYATC ; no epipodial tentacles on side of foot. No penis as fertilization external.

 

Internal anatomy visible with simple dissection

When shell is removed, whole mantle is exposed; part within U-shape shell-muscle is translucent so several features can be seen through it 20Tv flic.kr/p/sYGWq9 , but are more easily viewed if it is removed.

Key to images: 20Tv flic.kr/p/sYGWq9 , 21Tv flic.kr/p/sYFDp5 , 22Tv flic.kr/p/tdYS1N , 23Tv flic.kr/p/sjie7f , 24Tv flic.kr/p/tdYR6G , 25Tv flic.kr/p/tg3tWy , 26Tv flic.kr/p/sYHf5L ,

 

1: black or purple-black eye at base of cephalic tentacle. (images 21-24Tv)

2: yellow-buff odontophore supporting distal section of radula (image 24Tv)

3: buccal mass in translucent head (image 20-23Tv)

4: radula (images 23-26Tv)

5: radula sac enclosing proximal section of radula (24 & 26Tv)

6: yellow of radula visible through translucent head (images 22-23Tv)

7: roof of nuchal cavity (image 20Tv)

8: ctenidium, greatly contracted after death. (image 22Tv)

9: greyish stomach wall (images 20-21Tv)

10: digestive gland (images 20-21Tv)

11: rectum containing pale faecal pellets (image 23Tv)

12: yellow-buff male gonad (images 20-21Tv)

13: remains of ruptured female ovary (image 22Tv)

14: ova scattered from ovary (image 22Tv)

15: severed U shape shell-muscle (images 20-24Tv)

16: mantle skirt (images 20-22Tv & 24Tv)

17: muscles of left side of sole (image 24Tv)

18: jaw (image 26Tv)

cartilage of odontophore (image 25Tv)

 

Key identification features

Young Patella spp., can resemble worn specimens of T. testudinalis.

 

Tectura virginea

1) Maximum length 12 mm.

2) Shell exterior whitish/yellowish/bluish with pinkish or brownish rays and chains 11Tv flic.kr/p/tfYATC Worn specimens of T. virginea are often mistaken for T. testudinalis; examination of the foot and pallial groove or shell interior is necessary in such cases 34Tv flic.kr/p/2jcJrNh . Young T. virginea with blue spots 3Tv flic.kr/p/tg3WuB often confused with early stage Patella pellucida 36Tv flic.kr/p/2jcEoK7 .

3) Shell interior white, often shows exterior marks, sometimes red-brown V at vertex 2Tv flic.kr/p/sYsjKh .

4) Threadlike radial striae and fine concentric growth lines 2Tv flic.kr/p/sYsjKh often indistinct 1Tv flic.kr/p/tg3YWR

5) Mantle-skirt white, yellowish, or blue-green with inwardly oriented, large, white glands, and reddish bands on periphery 12 Tv flic.kr/p/tdUW2w 13 Tv flic.kr/p/tfYzmE & 14 Tv flic.kr/p/tdUUSs . Ctenidium, no pallial gills 16 Tv flic.kr/p/sYH1Lo .

6) Many unobtrusive, translucent processes on mantle edge, but no pallial tentacles 17 Tv flic.kr/p/sYPNR6 .

7) All Britain except NE Irish Sea and parts of SE England. On encrusted rock, not seaweeds.

8) Apex 18% to 30% of length from anterior 2 Tv flic.kr/p/sYsjKh .

 

Similar species

Testudinalia testudinalis (O. F. Müller, 1776)

1) Maximum length usually 20 mm, occasionally 25 mm 31Tv flic.kr/p/2jcH6iR .

2) Shell exterior matt-whitish with radiating dark brown rays that often bifurcate and reunite across the shell 30Tv flic.kr/p/2jcH6nd .

3) Shell interior porcelaneous-white with brown-banded peripheral border, and dark brown viscera patch, usually with pale vertex patch 33Tv flic.kr/p/2jcH6eh .

4) Fine concentric growth lines and radiating striae 32Tv flic.kr/p/2jcEoS6 .

5) Mantle skirt green in pallial groove, no red bands or large white glands on mantle periphery. Ctenidium, no pallial gills 34Tv flic.kr/p/2jcJrNh .

6) Large pallial tentacles protrude beyond shell perimeter when active 34Tv flic.kr/p/2jcJrNh .

7) North U.K, to Anglesey and N. Yorkshire. Many absence records, misleadingly, mapped further south on NBN with same symbol as for presence. On encrusted rock, not on seaweeds. records.nbnatlas.org/occurrences/search?q=lsid:NHMSYS0021...

8) Apex c. 25% to 40% of length from anterior 32Tv flic.kr/p/2jcEoS6 .

 

Patella pellucida Linnaeus, 1758 [early stage, length 2 to 7mm]

1) Maximum length of development stage 7 mm.

2) Shell exterior translucent pale horn to light brown with blue/green hyphens in longitudinal rows 36Tv flic.kr/p/2jcEoK7 . not in links of a chain pattern like that on some young T. virginea 3Tv flic.kr/p/tg3WuB .

3) Shell interior pale horn to light brown with black, colloidal particles under parts of the blue/green hyphens.

4) Smooth fragile shell 36Tv flic.kr/p/2jcEoK7 .

5) Mantle-skirt translucent whitish. Pallial gills, no ctenidium in nuchal cavity. No inwardly oriented, large, white repugnatorial glands or reddish bands on mantle periphery 35Tv flic.kr/p/2jcEoKC

6) pallial tentacles protrude from aperture rim, but unobtrusive as translucent and almost invisible 35Tv flic.kr/p/2jcEoKC .

7) All round Britain except Liverpool Bay and parts of SE England. On Laminaria, not rock, when > 2mm long.

8) Apex lost from anterior rim of aperture 36Tv flic.kr/p/2jcEoK7 .

  

Williamia gussoni (Costa O. G., 1829) 37Tv flic.kr/p/2jcJrJQ

1) Usual shell length c. 6 mm. Maximum L. c. 8 mm, W. 6 mm and H. 3 mm (Ruthensteiner, 2006); L. 8.8 mm (P. Ugarković, 2020 pers. comm.)

2) Exterior of shell is shiny, bright red-brown with c. 18 pale radiating rays that are sometimes obscured or faded when dead. Periostracum extends well beyond rim of shell.

3) Shell interior as exterior, but paler.

4) Thin, smooth shell with convex anterior and posterior slopes.

5) Mantle is translucent, red-brown with radiating, opaque white rays which correlate with pale rays of shell. No inwardly oriented, large, white repugnatorial glands. In Siphonariidae; respires with c. 17 lamellae concealed in mantle cavity; no pallial gills or protruding ctenidium plume.

6) No pallial tentacles. Cephalic tentacular lobes separated from large flat head by small cleft. Large flap-like anal lobe protrudes from mantle cavity on right. Dorsal surface of head and foot are red-brown; ventrally yellowish white

7) Common at Low Water to more than 50 m (J. Prkić, 2020, pers. comm.) in Adriatic, Mediterranean and adjacent Atlantic; not N.W. Europe (Ruthensteiner, 2006).

8) Apex has distinct semi-spiral protoconch positioned off-centre posteriorly, sometimes overhanging beyond the posterior of the aperture.

Habits and ecology

On rocky shores where turbidity doesn't prevent plant growth; at LWST (higher level if in pools) and to 100m depth. Occurs and feeds on pink Lithothamnion algae encrusting bedrock and stable stones 27Tv flic.kr/p/tdYPYw . Diatoms, Chondrus crispus and Cystoseira also reported as food (Fretter & Graham, 1962). So long as not arid, tops of encrusted stones and rocks apparently preferred, perhaps to avoid silt, but also where light allows Lithothamnion to grow. Hard iron-mineralized radula, longer than shell to allow for replacement of teeth worn away on rock, aided by pair of grab-like, lateral, chitinized jaws, 26Tv flic.kr/p/sYHf5L produces a distinctive network of feeding pits in surface of Lithothamnion 28Tv flic.kr/p/tgiReX ; initially paler-pink than undamaged surface but later bleaching white as Lithothamnion is killed 27Tv flic.kr/p/tdYPYw . Wide outer lip spreads out flat on substrate during feeding 11Tv flic.kr/p/tfYATC , contains many sensory structures; possible functions to detect Lithothamnion, locate mouth precisely to avoid overlap with previous feeding pit without missing part of food, and to retain loose fragments (function of anterior scraper-jaw on Patella spp.; missing from T. virginea). Long coiled intestine compacts faeces into firm white pellets 23Tv flic.kr/p/sjie7f that will not contaminate ctenidium near anus in nuchal cavity (T. virginea lacks a hypobranchial gland to produce mucus to bind faecal fragments). After defecation, pellets carried by exhalent respiratory current to posterior of animal to accumulate under shell 28Tv flic.kr/p/tgiReX before periodic sharp contraction of shell-muscle clamps shell down to expel water and faeces.

Defence: when on Lithothamnion, colour cryptic, and chain pattern 3Tv flic.kr/p/tg3WuB resembles feeding pits 28Tv flic.kr/p/tgiReX ; also shell often has covering of Lithothamnion 5Tv flic.kr/p/sj3eSy . Cilia-bearing sensory processes on outer edge of mantle 17Tv flic.kr/p/sYPNR6 probably sense attack. In response to strong stimulation (e.g. pressure from forceps) white repugnatorial glands on mantle-fringe 14Tv flic.kr/p/tdUUSs emit secretion of viscid, slow-to disperse, white threads (presumed by Fretter & Graham, 1962, to be distasteful and/or toxic) 29Tv flic.kr/p/t6rdC9 .

Breeds in spring (April-May in Roscoff); shedding of sperm into water by males (probably proximate, perhaps on female's shell like Testudinalia testudinalis) stimulates females to release eggs individually 22Tv flic.kr/p/tdYS1N . Eggs hatch as free trochophore larvae (stage passed within egg by most less “primitive” spp.) in plankton before transforming to veligers and, after a short pelagic life, settling and assuming limpet form with the white, semi-spiral, veliger shell at the apex as a protoconch 40Tv flic.kr/p/2jQTrLN . The protoconch is usually eroded away after the shell is about 1.5 mm long.

Respiration: cilia on ctenidium create inhalent water current into left of nuchal cavity, then between ctenidial filaments to oxygenate blood within, and thence as exhalent current along pallial groove on each side of foot to exit at posterior of limpet 18Tv flic.kr/p/tg1VSW . Although no pallial gills, respiration probably also occurs in pallial groove as most blood from head and pedal veins passes in veins through gaps between shell-muscle bundles into mantle and collects in peripheral efferent pallial vessel 18Tv flic.kr/p/tg1VSW (Fretter & Graham, 1962) that probably acquires oxygen from current generated by ctenidium and/or external water at shell's edge. Blood passes from efferent pallial vessel to heart without going through ctenidium 10Tv flic.kr/p/sjq6gF . When emersed, mantle cavity drains and ctenidium collapses, but roof of richly-vascularized cavity stays damp and functions for gas exchange sufficiently for respiration for short periods.

 

Distribution and status

Iceland and Kola Peninsula (N. Russia) to Senegal and into Mediterranean, not Baltic. GBIF map www.gbif.org/species/5191383 No record has been found of it living intertidally in the Mediterranean (J. Prkić, Croatia and G. Bazios, Greece, 2020, pers. comm.). Frequent all round Britain and Ireland on hard substrate in non-turbid water. Frequent all round Britain and Ireland on hard substrate in non-turbid water. It is absent, or rare, in Liverpool Bay and further south than Flamborough Head to Kent. U.K. map NBN species.nbnatlas.org/species/NHMSYS0021056385

 

Acknowledgements

I should like to thank Dr Ivan Nekhaev and Dr Julia Sigwart, for advice with the text and interpretation of the images. I thank Jakov Prkić and Pero Ugarković for information and use of images, Simon Taylor and Andrew Wright for specimens and Ann Wake and Allan Rowat for use of images. Any errors or omissions are the responsibility of the author.

 

Links and references

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1849), London, van Voorst. (As Acmaea virginea; Free PDF at archive.org/stream/historyofbritish02forb#page/436/mode/2up Use slide at base of page to select pp.437-440.)

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London.

 

Jeffreys, J.G. 1862-69. British conchology. vol. 3 (1865). London, van Voorst. (As Tectura virginea; Free PDF at archive.org/stream/britishconcholog03jeff#page/248/mode/2up . Use slide at base of page to select pp.248- 250.

 

Yonge, C.M. and Thompson, T.E. 1976. Living marine molluscs. London.

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=153552

 

GLOSSARY

 

aperture =– mouth of gastropod shell; outlet for head and foot.

cephalic =– (adj.) of or on the head.

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.

 

ELWS = extreme low water spring tide (usually near March and September equinoxes).

 

epipodial (adj.) = of the epipodium (collar or circlet running round sides of foot of some gastropods).

 

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

 

MLWS = mean low water spring tide level (mean level reached by lowest low tides for a few days every fortnight; Laminaria or Coralline zone on rocky coasts).

 

periostracum = thin horny layer of chitinous material often coating shells.

 

trochophore = spherical or pear-shaped larva that swims with aid of girdle of cilia. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for patellid limpets, most Trochidae and Tricolia pullus.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

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Are you in New Orleans? I'd love to hand you a copy in person so hit me up.

 

Lengths: 1) 11.6mm, 2) 12.1mm, 3) 13mm, 4) 13.2mm, 5) 14.2mm, 6) 12.1mm, 7) 13.9mm, 8) 12.2mm. Anteriors oriented upwards.

In Britain, sublittoral specimens usually grow up to 20mm long, 14mm wide, 10mm high, but 15mm is usual maximum length of intertidal specimens like these.

 

Full SPECIES DESCRIPTION BELOW

Key id. features: flic.kr/p/WNjbUS

APPENDIX re range advance/retreat: flic.kr/p/2jW74ig

Sets of OTHER SPECIES:

www.flickr.com/photos/56388191@N08/collections/

PDF version at www.researchgate.net/profile/Ian_Smith19/research

 

Testudinalia testudinalis (O.F. Müller , 1776).

Revised and Appendix added October 2020

Authors; Ian F. Smith (text) & Simon Taylor (shorework).

 

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=234208

Synonyms: Patella testudinalis O.F Müller, 1776; Patella tessulata O.F Müller, 1776; Acmaea tessulata (O.F Müller, 1776); Acmaea testudinalis (O.F Müller, 1776); Collisella tessulata (O.F Müller, 1776); Lottia testudinalis (O.F Müller, 1776); Tectura tessulata (O.F Müller, 1776); Tectura testudinalis (O.F Müller, 1776); Testudinalia tessulata (O.F Müller, 1776);

 

Vernacular names: Northern tortoiseshell limpet (English); Brenigen fraith (Welsh); Schildkrötenschnecke (German); Skilpaddesnegl (Norwegian); Sköldpaddskålsnäcka (Swedish); Atlantic plate limpet (USA);

The former English vernacular was 'Common tortoiseshell limpet', but it is rare or absent in England so it was changed in October 2020 to 'Northern' on UK Species Inventory to reduce frequency of misidentification of Tectura virginea, the 'White tortoiseshell limpet' as Testudinalia testudinalis.

GLOSSARY below.

 

Shell Description

In Britain, sublittoral specimens usually up to 20mm long, 14mm wide, 10mm high, but 15mm is usual maximum length of intertidal specimens 1Tt flic.kr/p/WadzLk & 2Tt flic.kr/p/WNjbUS . Extreme maximum length 30mm in Britain; may be larger in USA (Jeffreys, 1865). Shell rather thin and easily damaged when prising a specimen off substrate. Usually a low conoid, shell height about 25% to 36% of length 3Tt flic.kr/p/X8KE25 . Eccentric apex tilted forwards, varies about 25% to 40% of shell-length from anterior. Minute spiral coil shell of veliger larva survives on apex until shell 1mm long. Aperture rim an ellipse; posterior and anterior usually similar breadth 4Tt flic.kr/p/XbymyT .

 

Anterior profile almost flat with small shallow concavity that diminishes when adjacent tilted apex is eroded; posterior profile flat to slightly convex 3Tt flic.kr/p/X8KE25 . Superficially smooth, but major growth lines, and many finer ones, run concentrically around the shell 5Tt flic.kr/p/XoDw7c ; spacing between them is closer on the anterior as growth is more rapid at the posterior. Consequently, the lines, seen from the side, have a downward tilt towards the anterior 6Tt flic.kr/p/X8KABj Many fine ridges radiate from the apex, though they are often eroded near it. The visibility of the radiating lines and growth lines of an individual shell varies with the viewing conditions, and they may be eroded from some or most of a shell 7Tt flic.kr/p/X8KAeL . Shell matt, opaque or slightly translucent. External ground colour of live, clean shell lacking epizoic growths is whitish; sometimes slightly darkened or greenish if shell translucent enough to transmit colour of shell interior or mantle 8Tt flic.kr/p/WCkgDH . Brown and blackish brown marks radiate from the apex, bifurcating and reuniting to form a reticulated pattern that may be a wide open net with the white ground colour dominant 9Tt flic.kr/p/WMzPt9 , but, very often, brown predominates forming a tessellation of approximately rectangular, brown marks 10Tt flic.kr/p/X8KwDE which may merge to create a generally brown shell 11Tt flic.kr/p/X8KuKE . Shell may be colourless transparent showing the green mantle and dark shell interior, occasionally on adults 12Tt flic.kr/p/XfRgGQ and frequently on small juveniles 13Tt flic.kr/p/WCkfdX . Shell colour of live specimens may be affected by closely adhering thin coating of brown or green algae 14Tt flic.kr/p/X8Kt81 . Colours are less bright on dry shells, but, usually, growth lines are more distinct. Internally, shell 4Tt flic.kr/p/XbymyT has 1) an aperture rim coloured as exterior; secreted by the yellow to mustard brown mantle-edge 15Tt flic.kr/p/X8KpLb , 2) a wide, matt white, peripheral zone 16Tt flic.kr/p/XoDmd4 ; secreted by the green mantle-skirt, 3) a very thin, whitish mantle-attachment scar 17Tt flic.kr/p/X8KpZN , most distinct at the anterior where it is not flanked by 4) the narrow, glossy, white U-shape pedal-retractor muscle scar, 5) an amphora shaped, chocolate brown area enclosed by scars 3 & 4; secreted by green mantle over visceral hump and 6) a cream/orange/pale brown patch at the vertex.

 

Body description

Main colour of flesh is white or yellowish white 18Tt flic.kr/p/Wadmi8 . Head has short stout snout with a large mouth. Large,extendible, outer lips have a gap ventrally which can be held closed or open 19Tt flic.kr/p/WNjiGE . The lips can be held in a variety of positions, sometimes resembling a large snout 20Tt flic.kr/p/XpnWWD & 21Tt flic.kr/p/Xksgvu . The lips are thin and flimsy when extended, but are reinforced internally by longitudinal ribs that, when held together, give the lips a wavy edge 19Tt flic.kr/p/WNjiGE . A pink, internal odontophore can be seen through the translucent, white head 19Tt flic.kr/p/WNjiGE & 18Tt flic.kr/p/Wadmi8 . The odontophore is separated from the outer lips by the yellowish inner lips that open laterally and close to a vertical line . When they open, the radula with rust-coloured iron rich teeth is protruded. The long, slender, white, unpigmented cephalic tentacles are up to 70% of shell length when fully extended 20Tt flic.kr/p/XpnWWD . The tiny eye on the base of each tentacle dorsally is a deep, narrow pit, detectable in the translucent tentacle as a black line running in to a broader black spot 18Tt flic.kr/p/Wadmi8 . When viewed ventrally through the tentacle, the broad internal spot is faintly discernible 19Tt flic.kr/p/WNjiGE . Some or all of the black may be pigmented retinal cells. The eye can probably differentiate light from shade, and detect the direction of the light source, but cannot discern shapes. The mantle is translucent and colourless but usually covered with a dense layer of removable pigment; emerald green apart from a peripheral mustard brown border 15Tt flic.kr/p/X8KpLb . When viewed ventrally on a live specimen, only the mantle skirt is visible and the colours are affected by the adjacent shell interior and by being seen through the mantle, so the emerald green pigment often looks blue-green, and the periphery shows the dark shell through translucent white 17Tt flic.kr/p/X8KpZN . The mantle skirt contains the peripheral efferent pallial vessel 22Tt flic.kr/p/XpnWLZ and is fringed with translucent, white pallial tentacles 23Tt flic.kr/p/Xksgfj . The mantle cavity consists of a nuchal cavity over the head, and a wide pallial groove around the entire periphery of the foot-head. Unlike patellid limpets, it has no pallial gills in the pallial groove, but does have a large, extendible, bipectinate ctenidium attached to the left of the nuchal cavity that, when extended, projects from the right of the nuchal cavity 24Tt flic.kr/p/XpnWp6 & 25Tt flic.kr/p/XksfKb . The lamellae on the right of the ctenidium are large, but those on the left are small and often hidden from view, so the ctenidium may appear monopectinate. The pedal-retractor muscle, a U of white muscle bundles separated by narrow gaps, attaches the body/foot to the shell 26Tt flic.kr/p/XpnW7c & 18Tt flic.kr/p/Wadmi8 . Sole and sides of foot white or pale yellowish white. Sole approximately circular when fully spread 22Tt flic.kr/p/XpnWLZ . Sides of foot lack features such as epipodial tentacles. When crawling, usually only the extended pallial tentacles, cephalic tentacles and, occasionally, the ctenidium protrude beyond the shelter of the shell 23Tt flic.kr/p/Xksgfj . No penis as fertilization is external.

 

Internal functional anatomy

 

Blood circulation and respiration

Image links: 22Tt flic.kr/p/XpnWLZ , 24Tt flic.kr/p/XpnWp6 , 25Tt flic.kr/p/XksfKb .

Small vessels carry oxygen-depleted, colourless blood from the visceral mass through gaps between the muscle bundles of the pedal retractor muscle (24Tt ) and through the green mantle skirt (22Tt ) to the efferent pallial vessel.

The large, peripheral, efferent pallial vessel (22Tt & 24Tt ) carries oxygen-depleted blood round the entire animal between zones 1 & 2 of the mantle skirt.

Blood in the efferent pallial vessel travels forwards on both sides, that on the right passes round in front of the head to the left where two vessels (22Tt) carry the blood into the nuchal cavity where it passes through the ctenidium (24Tt ) to be oxygenated and then recirculated to the body.

The green ctenidium is attached within the left of the nuchal cavity . When the limpet is in motion, the ctenidium protrudes from the right of the cavity(24Tt) and may extend beyond the rim of the shell. At rest, it often contracts 50% and is concealed within the cavity. It consists of a substantial axis (24Tt & 25Tt ) with many lamellae (24Tt & 25Tt) resembling the teeth of a comb attached to each side; bipectinate arrangement. The lamellae on the right of the axis are large (24Tt & 25Tt), but those on the left are small (25Tt), restricted to the distal part of the axis, and often hidden from view so the ctenidium may appear monopectinate 24Tt.

The inhalant current of oxygen-bearing seawater enters the nuchal cavity from the left 26Tt flic.kr/p/XpnW7c and passes between the lamellae which absorb the oxygen for blood flowing through them. The oxygenated blood flows into the large branchial efferent vessel (24Tt & 25Tt) in the axis and thence to the heart (25Tt) near the base of the ctenidium to be recirculated through the body. Exhalant water currents pass along the pallial groove on either side of the body to exit at the mid-point of the posterior 26Tt flic.kr/p/XpnW7c .

Alimentary and excretory features .

The inner lips of the mouth, described above, open into the buccal cavity. Dissection shows that the anterior wall of the cavity is reinforced by a pliable, white, chitinous, antero-dorsal plate, called the “jaw” though it is not articulated and does not bite 27Tt flic.kr/p/Xksf1q . It serves as an attachment for several muscles and has two lateral wings that meet dorsally at an angle and form an anterior shield for the inner lips when they are open. Within the buccal cavity there is a large pink odontophore 27Tt flic.kr/p/Xksf1q consisting of a right and left bolster which is covered in thick cuticle. Much of the bolsters is made of strong cartilage-like material.

The anterior of the radula, widened into a hyaline shield, rests on the dorsum of the odontophore and is recessed slightly into the groove between the bolsters 27Tt flic.kr/p/Xksf1q . The strong, iron-impregnated, unarticulated teeth are firmly fixed in a backwardly inclined position on the radula, but the anterior tip of the radula bends over the front of the odontophore so that the front row of four teeth are inclined forwards like a chisel 27Tt flic.kr/p/Xksf1q . To feed, the strong muscles of the odontophore thrust it forwards against the front of the buccal cavity which, reinforced by the jaw, restrains the odontophore but allows the front teeth to project strongly from the narrow vertex of the gap between the wings of the jaw. When applied to the substrate, the teeth easily loosen diatoms, algae and other growths coating bedrock and boulders, and the curve of the withdrawing teeth acts as a scoop to lift particles back to the oesophagus in the buccal cavity. The action is surrounded by the outer lips which prevent the escape of loosened food fragments. Marks left by the front four teeth on the printed surface of a polythene sheet show that specimens with shells c. 14mm long make straight thrusts of about 0.5mm at each stroke 28Tt flic.kr/p/XpnVJD . Like other limpets and some sea snails that graze rock surfaces, T. testudinalis has a radula considerably longer than its shell 29Tt flic.kr/p/XkseKq which requires several folds to fit it inside its body 30Tt flic.kr/p/XpnUSP . The cause of the correlation between length and rock grazing is uncertain. It may be that a lengthy process is needed for the teeth to acquire the required hardening mineralization. Tooth creation starts at the slightly bifid, white, inner end of the long radular sac 31Tt flic.kr/p/XksdD7 with secretion of colourless transparent cuticular material by odontoblast cells. As each new tooth commences, the previous one is pushed forwards along the sac. Cells along the roof of the sac make incremental additions, including the hardening salts of iron and silicon, to the teeth as they travel along the sac, with a progressive change from colourless through darkening shades of yellow/orange visible through the translucent sac walls. Creation is complete by the time the tooth reaches the buccal cavity, where it emerges from the radular sac onto the odontophore in front of the opening of the oesophagus.

A whitish salivary duct runs next to each of the two dorsal folds of the oesophagus 32Tt flic.kr/p/XpnUP2 . The ducts carry mucus from the salivary gland to the buccal cavity to lubricate the feeding process and bind the food particles brought in by the radula. The mucus does not have a digestive function. In the rear of the buccal cavity, the mucus-bound food particles pass into the entrance of the oesophagus 32Tt flic.kr/p/XpnUP2 and the radula passes into the radular sac directly below the oesophagus (so now out of sight in dorsal view, except for a short section usually visible at the surface of the digestive gland 33Tt flic.kr/p/Xksdxf ). Lubricating mucus is provided to the oesophagus by the oesophageal gland consisting of a series of tubules on either side of it 32Tt flic.kr/p/XpnUP2 . The oesophagus passes into the visceral mass. Food is moved along it by cilia to where it widens to become the stomach. The digestive gland 33Tt flic.kr/p/Xksdxf , composed of a mass of tubules and usually the most obvious organ on the surface of the visceral mass when the shell is removed, opens into the stomach through a duct. Digestive cells in the tubules ingest particulate food to digest it intracellularly (Fretter & Graham, 1994, p. 219). The tubules extend into the blood filling the haemocoel, and their very thin covering of connective tissue allows the passage of nutrients into the blood. Undigested material passes into the long coiled intestine 33Tt flic.kr/p/Xksdxf where it is compressed and bound with mucus 28Tt flic.kr/p/XpnVJD to prevent fouling of the ctenidium. The faecal string passes through the rectum 33Tt flic.kr/p/Xksdxf to emerge from the anus at the rear right of the nuchal cavity and, with particulate matter removed by cilia from the inhalant water, is conveyed along the pallial groove by cilia, helped by the flow of exhalant water, to be expelled from the mid-point of the posterior of the shell 26Tt flic.kr/p/XpnW7c . The large right nephridium ( kidney) is attached to the inner surface of the mantle 34Tt flic.kr/p/WNje2h , but often difficult to distinguish when it is the same colour as the viscera below it 33Tt flic.kr/p/Xksdxf . The right nephridium extends round onto the left of the animal. The nephridipores (openings) of it and the smaller, unobtrusive, left nephridium are sometimes visible 34Tt flic.kr/p/WNje2h on either side of the anus . Their urogenital products are conducted to the posterior of the animal by cilia and the exhalant water current.

 

Reproductive organs

The gonads are situated between the viscera and foot. Just before and during breeding, they may spread over much of the viscera, but they are usually hidden, apart from a small section, on an animal removed from the shell. If the mantle is taken off a female, her ovaries may rapidly expand as the ova absorb water and the constraint of the mantle is removed 35Tt flic.kr/p/XpnUtT . Female ovaries are granular, and individual red/brown ova readily break away 36Tt flic.kr/p/WNjcRm . Male testes have numerous interconnected tubules 37Tt flic.kr/p/W8wFmq . Male and female gonads have similar orange-brown colours, or pink (Fox, 2003), with individual variation of shade which may change with breeding condition. Fertilization is external, so the male has no penis. Gametes leave both sexes through the right nephridium (kidney) via its nephridipore 34Tt flic.kr/p/WNje2h close to the anus in the nuchal cavity. The female also exudes a thin mucous film that secures the ova to the substrate.

 

Key identification features

Testudinalia testudinalis

1: Maximum length usually 20mm, occasionally 25mm, rarely 30mm.

2: Shell exterior matt-whitish with radiating chocolate-brown rays that often bifurcate and reunite across the shell 1Tt flic.kr/p/WadzLk .

3: Shell interior porcelaneous-white with brown-banded peripheral border, an amphora-shaped, chocolate-brown patch and a pale vertex patch 4Tt flic.kr/p/XbymyT .

4: No prominent sculpture (except sometimes irregular repair-line of damage), but many fine concentric growth lines and radiating striae 5Tt flic.kr/p/XoDw7c .

5: Mantle skirt with emerald green pigment dorsally that looks blue-green when viewed ventrally 17Tt flic.kr/p/X8KpZN .

6: Large pallial tentacles protrude beyond shell perimeter when active 23Tt flic.kr/p/Xksgfj .

7: Northern species stretching south to southern Scotland, northern Ireland, Isle of Man, south-west Sweden and Rhode Island, USA.

8: Sometimes, but more often not, on pink, calcareous, encrusting algae with no pale feeding pits, and faecal rods with flat truncated ends that are not chalk-white.

 

Similar species

 

Tectura virginea

The only ‘tortoiseshell limpet’ in the southern half of Britain where it is often mis-recorded as Testudinalia testudinalis.

1: Maximum length 12mm.

2: Shell exterior whitish/yellowish/bluish with radiating pinkish rays and/or light-brown chains which are often mistaken for brown marks of T. testudinalis, especially small juveniles 42Tt flic.kr/p/XASHRd .

3: Shell interior white often translucent showing exterior marks, sometimes red-brown V near vertex 43Tt flic.kr/p/WCkdUp .

4: Sculpture of slight threadlike radiating striae 43Tt flic.kr/p/WCkdUp , often indistinct or absent 44Tt flic.kr/p/XASHz1 , and numerous fine concentric growth lines

5: Mantle-skirt white, yellowish, or blue-green with reddish bands on periphery 45Tt flic.kr/p/XfRfyN , 46Tt flic.kr/p/WA5eV5 and 47Tt flic.kr/p/XASHvo .

6: Outer edge of mantle has many small, unobtrusive, translucent processes and many large white repugnatorial glands pointing inwards from mantle edge, but no prominent outward pointing pallial tentacles 48Tt flic.kr/p/XRRcsx .

7: All round Britain except Liverpool Bay and parts of SE England.

8: Nearly always on pink, calcareous, encrusting algae with pale feeding pits and short, chalk-white faecal rods with hemispherical ends.

Habits and ecology

T. testudinalisoccurs on rocky shores at MLWST, or MHWNT in pools, and to 50m depth. It feeds on diatoms and algae 12Tt flic.kr/p/XfRgGQ coating bedrock and boulders. Eulittoral specimens are often found stationary on bare vertical 38Tt flic.kr/p/XASJfQ or overhanging 39Tt flic.kr/p/WCkeDv surfaces during daylight hours. Fretter and Graham (1962) say it and Tectura virginea feed on encrusting algae but, though T. virginea is usually found on/near it, only 18 of 300 images of T. testudinalis on iNaturalist show encrusting algae. Lord (2008) showed that immersed laboratory specimens fed nocturnally on alga-encrusted rocks but in daylight moved onto bare vertical rocks, where they remained stationary. A homing instinct, if any, is weakly developed in this species, so a home scar is not engraved into soft rock (Lord, 2008).

Defence: the simple eyes 18Tt flic.kr/p/Wadmi8 may be able to detect the shadow of an attacker, but the principal warning organs are probably the touch-sensitive, long cephalic tentacles, plentiful encircling pallial tentacles 23Tt flic.kr/p/Xksgfj and large outer lips 20Tt flic.kr/p/XpnWWD. The white and brown tessellated shell is probably cryptic on the bare rocks favoured in daylight 8Tt flic.kr/p/WCkgDH. Predators include gulls, crabs and starfish. When threatened by a starfish, it exhibits, like small Patella vulgata, a flight response (Lord, 2008).

T. testudinalis breeds in spring and early summer (April to July in New England). Gonochoristic; the male lacks a penis, but he mounts a female's shell, sometimes for several hours in expectation, to be proximate when she spawns so he can release his sperm to be drawn in by her inhalent current as the eggs emerge 40Tt flic.kr/p/W8wF1A. In a refrigerator maintained at about 8ºC, some of a group of eight individuals, collected in late May, bred in June producing a thin film of mucus with the ova widely spaced and attached to it (pers. obs.). The film was only loosely attached to the smooth base of the container, but adhesion would probably be better on a rough surface. The eggs hatched by late June as free trochophore larvae (stage passed within egg by most less “primitive” spp.) but further development failed. In the wild, after a short time in the plankton, the trochophores metamorphose into veligers and, after further growth in the plankton, settle and assume limpet form by August with a thin, translucent, 2 mm long shell 13Tt flic.kr/p/WCkfdX .

 

Distribution and status

T. testudinalis is a cold-water, northern species in Arctic Canada, Greenland, Iceland and northern Russia, which extends south to Rhode Island (USA), Britain, Ireland, southern Scandinavia and the German Baltic, but not the brackish inner Baltic. In the relatively cold 19th century is extended its range southwards in Britain, Ireland and probably elsewhere, except the Baltic and Gulf of St Lawrence where low salinity probably prevented its spread. In the late 20th century and early 21st century, when temperatures rose markedly at an increasing rate, its distribution seems to have fallen back northwards to about its pre-spread positions.

The appendix at flic.kr/p/2jW74ig describes in detail the distribution limits at different dates.

  

Acknowledgements

I am indebted to Simon Taylor and David W. McKay for providing me with specimens for photography and study. The account would not have been possible without their help. I thank Dr Paula Lightfoot and Becky Hitchin for generously providing images and information. The much valued advice of Dr Julia Sigwart and Dr Lauren Sumner-Rooney is gratefully acknowledged. Many thanks also to Inga Williamson for shore work related to the account.

A separate acknowledgement is made after the Appendix at flic.kr/p/2jW74ig of those who contributed to its creation.

 

Links and references

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1849), London, van Voorst. (As Acmaea testudinalis; Free PDF at archive.org/stream/historyofbritish02forb#page/434/mode/2up Use slide at base of page to select pp.434-437.)

 

Fox, R. 2003. Invertebrate Anatomy On Line; Tectura testudinalis

lanwebs.lander.edu/faculty/rsfox/invertebrates/tectura.html

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

GBIF (Global Biodiversity Information Facility). Distribution map for T. testudinalis accessed October 2020. Includes many obvious errors such as far-inland or tropical locations. www.gbif.org/species/4369953

 

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London.

 

Hargreaves, J. A. 1910. The marine mollusca of the Yorkshire coast and the Dogger Bank. J. Conch., Lond. 13: 80 – 105.

 

iNaturalist map and images of T. testudinalis records (accessed October 2020) www.inaturalist.org/taxa/415169-Testudinalia-testudinalis

 

Jeffreys, J.G. 1862-69. British conchology. vol. 3 (1865). London, van Voorst. (As Tectura testudunalis; Free PDF at archive.org/stream/britishconcholog03jeff#page/246/mode/2up . Use slide at base of page to select pp.246- 248.

 

Lebour, M.V. 1902. Marine mollusca of Sandsend. The Naturalist.

 

Lord, J. 2008. Movement patterns and feeding behaviour of the limpet Tectura testudinalis (Müller) along the mid-Maine Coast Honors Theses. Paper 243. digitalcommons.colby.edu/honorstheses/243

 

Lumb, F.E. 1961. Seasonal variation of the sea surface temperature in coastal waters of the British Isles. Scientific paper no. 6. London, HMSO.

pdf at digital.nmla.metoffice.gov.uk/file/sdb%3AdigitalFile%7Cc2...

 

McMahon, R. F. & Russell-Hunter, W. D. 1977. Temperature relations of aerial and aquatic respiration in six littoral snails in relation to their vertical zonation. Biol. Bull. 152: 182 to198.

Publication info: Woods Hole, Mass. :Marine Biological Laboratory,

View at www.biodiversitylibrary.org/page/1540015#page/202/mode/1up

whole bulletin is 38 MB, but page has option to create 5MB pdf of just the article by selecting pp 182 to 198

www.biodiversitylibrary.org/pdf4/066873200017332.pdf

 

Mieszkowska, N., Leaper, R., Moore, P., Kendall, M.A., Burrows, M.T, Lear, D., Poloczanska, E., Hiscock, K., Moschella, P.S., Thompson,R.C., Herbert, R.J., Laffoley, D., Baxter, J., Southward, A.J., & Hawkins, S.J. 2005. Assessing and predicting the influence of climatic change using eulittoral rocky shore biota. M.B.A. Occasional publication No. 20.

www.researchgate.net/publication/281164392_Assessing_and_...

  

Parker, D.E., T.P. Legg, and C.K. Folland. 1992. A new daily Central England Temperature Series, 1772-1991. Int. J. Clim., Vol 12, pp 317-342 www.metoffice.gov.uk/hadobs/hadcet/ [includes update to 2020].

 

Walker, C.G. 1966. Studies on the jaw, digestive system, and coelomic derivatives in representatives of the genus Acmaea. In Abbot, D.P. et al (ed.). 1968. The biology of Acmaea. Veliger 11: supplement. 88 to 97.

pdf at archive.org/details/veliger111968berk

 

Yonge, C.M. and Thompson, T.E. 1976. Living marine molluscs. London.

 

Current taxonomy: World Register of Marine Species (WoRMS)

www.marinespecies.org/aphia.php?p=taxdetails&id=234208

 

GLOSSARY

 

afferent = (adj. of vessel) carrying blood etc. towards an organ.

aperture = mouth of gastropod shell; outlet for head and foot.

auricle = part of heart that receives blood from the adjacent ctenidium.

bipectinate = (See ctenidium.)

cartilages = (in gastropods) structures of tough, resilient material, histologically resembling vertebrate cartilage, embedded in tough connective tissue of left and right bolsters of the odontophore. Support and maintain shape of odontophore, and provide attachment for muscles controlling its movement.

 

cephalic = (adj.) of or on the head.

coll. = in the collection of (named person or institution; compare with leg.).

comminuted = reduced to minute particles or fragments.

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments/lamellae on either side (bipectinate), sometimes on one side only (monopectinate).

 

efferent = (adj. of vessel) carrying blood etc. away from an organ.

ELWS = extreme low water spring tide (usually near March and September equinoxes).

emersed = not covered in water.

epipodial = (adj.) of the epipodium (collar or circlet running round sides of foot of some gastropods).

 

gonochor(ist)ic = (syn. dioecious) having separate male and female individuals, not hermaphrodite.

 

growth line = line, transverse to direction of shell increase, indicating aperture's rim position during a pause in growth. Seasonal pauses create more major lines than shorter pauses such as diurnal ones.

 

haemocoel = blood-filled body cavity of gastropods. (Molluscs have an “open circulatory system” which includes large cavities with sluggishly moving blood that directly bathes organs.)

 

immersed = covered in water.

intracellularly = occurring within a cell or cells.

lamellae (of ctenidium) = plate like leaflets/filaments arranged like teeth of a comb.

 

leg. (abbreviation of legit) = collected/ found by (compare with coll.)

mantle = sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs.

 

monopectinate = (See ctenidium.)

MLWS = mean low water spring tide level (mean level reached by lowest low tides for a few days every fortnight; Laminaria or Coralline zone on rocky coasts).

 

nephridium (pl. nephridia) = cilia-lined excretory/osmoregulatory tubule (kidney).

 

nephridiopore = opening of nephridium (kidney) for excretion. a.k.a. nephropore, or renal pore.

 

nuchal cavity = cavity roofed by mantle that contains head of limpet; part of mantle cavity (remainder consists of pallial groove on each side of body).

 

pericardium= sac containing the heart.

periostracum = thin horny layer of chitinous material often coating shells.

protandrous hermaphrodite = sequential hermaphrodite with individuals starting as males and later changing to female.

 

trochophore = spherical or pear-shaped larva that swims with aid of girdle of cilia. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for patellid limpets, most Trochidae and Tricolia pullus.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

 

ventricle = contractile part of heart that pumps blood.

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SLO CAL Surf Open, Pismo Beach California, Surfing for Hope

 

Wikipedia, This glossary of surfing includes some of the extensive vocabulary used to describe various aspects of the sport of surfing as described in literature on the subject.[a][b] In some cases terms have spread to a wider cultural use. These terms were originally coined by people who were directly involved in the sport of surfing.

 

About the water

 

Breaking swell waves at Hermosa Beach, California

See also: surf break

A-Frame: Wave with a peak that resembles an A and allows surfers to go either left or right, with both sides having a clean shoulder to work with.[1]

Barrel: (also tube, cave, keg, green room) The effect when a big wave rolls over, enclosing a temporary horizontal tunnel of air with the surfer inside[c]

Beach break: An area with waves that are good enough to surf break just off a beach, or breaking on a sandbar farther out from the shore[c]

Big sea: Large, unbreaking surf[2]

Blown out: When waves that would otherwise be good have been rendered too choppy by wind[c]

Bomb: An exceptionally large set wave[d]

Bottom: Refers to the ocean floor, or to the lowest part of the wave ridden by a surfer[2]

Channel: A deep spot in the shoreline where waves generally don't break, can be created by a riptide pulling water back to the sea and used by surfers to paddle out to the waves[2]

Chop or choppy: Waves that are subjected to cross winds, have a rough surface (chop) and do not break cleanly [d]

Close-out: A wave is said to be "closed-out" when it breaks at every position along the face at once, and therefore cannot be surfed[3]

Crest: The top section of the wave, or peak, just before the wave begins to break [4]

Curl: The actual portion of the wave that is falling or curling over when the wave is breaking[4]

Face: The forward-facing surface of a breaking wave [c]

Flat: No waves[c]

Glassy: When the waves (and general surface of the water) are extremely smooth, not disturbed by wind [c]

Gnarly: Large, difficult, and dangerous (usually applied to waves) [c]

Green: The unbroken portion of the wave, sometimes referred to as the wave shoulder[2]

Inshore: The direction towards the beach from the surf, can also be referring to the wind direction direction traveling from the ocean onto the shore[2]

Line-up: The queue area where most of the waves are starting to break and where most surfers are positioned in order to catch a wave[a]

Mushy: A wave with very little push[3]

Off the hook: An adjective phrase meaning the waves are performing extraordinarily well [c]

Outside: Any point seaward of the normal breaking waves[3]

Peak: The highest point on a wave[2]

Pocket: The area of the wave that's closest to the curl or whitewash. Where you should surf if you want to generate the most speed. The steepest part of a wave, also known as the energy zone.

Pounder: An unusually hard breaking wave[3]

Point break: Area where an underwater rocky point creates waves that are suitable for surfing[c]

Riptide: A strong offshore current that is caused by the tide pulling water through an inlet along a barrier beach, at a lagoon or inland marina where tide water flows steadily out to sea during ebb tide

Sections: The parts of a breaking wave that are rideable[c]

Sectioning: A wave that does not break evenly, breaks ahead of itself[2]

Set waves: A group of waves of larger size within a swell[c]

Shoulder: The unbroken part of a breaking wave[c]

Surf's up: A phrase used when there are waves worth surfing[2]

Swell: A series of waves that have traveled from their source in a distant storm, and that will start to break once the swell reaches shallow enough water

Trough: The bottom portion of the unbroken wave and below the peak, low portion between waves[2][4]

Undertow: An under-current that is moving offshore when waves are approaching the shore[2]

Wall: The section of the wave face that extends from the shoulder to the breaking portion, where the wave has not broken and where the surfer maneuvers to ride the wave[4]

Wedge: Two waves traveling from slightly different direction angles that converge to form a wedge when they merge, where the wedge part of the two waves usually breaks a great deal harder than the individual waves themselves[2]

Whitecaps: The sea foam crest over the waves[2]

Whitewater: In a breaking wave, the water continues on as a ridge of turbulence and foam called "whitewater"[d] or also called "soup"[4]

Techniques and maneuvers

 

Tandem surfing

 

Tube riding at Teahupo'o (Tahiti)

Air/Aerial: Riding the board briefly into the air above the wave, landing back upon the wave, and continuing to ride[d]

Backing out: pulling back rather than continuing into a wave that could have been caught[2]

Bail: To step off the board in order to avoid being knocked off (a wipe out)[d]

Bottom turn: The first turn at the bottom of the wave[d]

Carve: Turns (often accentuated)

Caught inside: When a surfer is paddling out and cannot get past the breaking surf to the safer part of the ocean (the outside) in order to find a wave to ride[d]

Cheater five: See Hang-five/hang ten

Cross-step: Crossing one foot over the other to walk down the board

Drop in: Dropping into (engaging) the wave, most often as part of standing up[d]

"To drop in on someone": To take off on a wave that is already being ridden. Not a legitimate technique or maneuver. It is a serious breach of surfing etiquette.[5]

Drop-knee: A type of turn where both knees are bent where the trail or back leg is bent closer to the board than the lead or front leg knee[2]

Duck dive: Pushing the board underwater, nose first, and diving under an oncoming wave instead of riding it[d]

Fade: On take-off, aiming toward the breaking part of the wave, before turning sharply and surfing in the direction the wave is breaking, a maneuver to stay in the hottest or best part of the wave[2]

Fins-free snap (or "fins out"): A sharp turn where the surfboard's fins slide off the top of the wave[f]

Floater: Riding up on the top of the breaking part of the wave, and coming down with it[c]

Goofy foot: Surfing with the left foot on the back of board (less common than regular foot)[d]

Grab the rail: When a surfer grabs the board rail away from the wave[3]

Hang Heels: Facing backwards and putting the surfers' heels out over the edge of a longboard[6]

Hang-five/hang ten: Putting five or ten toes respectively over the nose of a longboard

Kick-out: Surfer throwing their body weight to the back of the board and forcing the surfboard nose straight up over the face of the wave, which allows the surfer to propel the board to kick out the back of the wave[4]

Head dip: The surfer tries to stick their head into a wave to get their hair wet[3]

Nose ride: the art of maneuvering a surfboard from the front end

Off the Top: A turn on the top of a wave, either sharp or carving[6]

Pop-up: Going from lying on the board to standing, all in one jump[d]

Pump: An up/down carving movement that generates speed along a wave[d]

Re-entry: Hitting the lip vertically and re-reentering the wave in quick succession.[d]

Regular/Natural foot: Surfing with the right foot on the back of the board[d]

Rolling, Turtle Roll: Flipping a longboard up-side-down, nose first and pulling through a breaking or broken wave when paddling out to the line-up (a turtle roll is an alternative to a duck dive)[d]

Smack the Lip /Hit the Lip: After performing a bottom turn, moving upwards to hit the peak of the wave, or area above the face of the wave.[7]

Snaking, drop in on, cut off, or "burn": When a surfer who doesn't have the right of way steals a wave from another surfer by taking off in front of someone who is closer to the peak (this is considered inappropriate)[d]

Snaking/Back-Paddling: Stealing a wave from another surfer by paddling around the person's back to get into the best position[d]

Snap: A quick, sharp turn off the top of a wave[6]

Soul arch: Arching the back to demonstrate casual confidence when riding a wave

Stall: Slowing down by shifting weight to the tail of the board or putting a hand in the water. Often used to stay in the tube during a tube ride[c]

Side-slip: travelling down a wave sideways to the direction of the board[8]

Switchfoot: Ambidextrous, having equal ability to surf regular foot or goofy foot (i.e. left foot forward or right foot forward)

Take-off: The start of a ride[9]

Tandem surfing: Two people riding one board. Usually the smaller person is balanced above (often held up above) the other person[f]

Tube riding/Getting barreled: Riding inside the hollow curl of a wave

Accidental

"Over the falls" redirects here. For other uses, see Over the falls (disambiguation).

 

Wipeout

Over the falls: When a surfer falls off the board and the wave sucks them up in a circular motion along with the lip of the wave. Also referred to as the "wash cycle", being "pitched over" and being "sucked over"[e]

Wipe out: Falling off, or being knocked off, the surfboard when riding a wave[e]

Rag dolled: When underwater, the power of the wave can shake the surfer around as if they were a rag doll[10]

Tombstone: When a surfer is held underwater and tries to climb up their leash, which positions the board straight up and down[e]

Pearl: Accidentally driving the nose of the board underwater, generally ending the ride[d]

About people and behavior

 

Grommet on a board with his dad watching.

Dilla: A surfer who is low maintenance, without concern, worry or fuss. One who is confidently secure in being different or unique.[11]

Grom/Grommet/Gremmie: A young surfer[a]

Hang loose: Generally means "chill", "relax" or "be laid back". This message can be sent by raising a hand with the thumb and pinkie fingers up while the index, middle and ring fingers remain folded over the palm, then twisting the wrist back and forth as if waving goodbye, see shaka sign

Hodad: A nonsurfer who pretends to surf and frequents beaches with good surfing[12]

Kook: A wanna-be surfer of limited skill[13][14]

Waxhead: Someone who surfs every day[e]

About the board

Further information on surfboards: Surfboard

 

Waxing a surfboard

Blank: The block from which a surfboard is created

Deck: The upper surface of the board

Ding: A dent or hole in the surface of the board resulting from accidental damage[a]

Fin or Fins: Fin-shaped inserts on the underside of the back of the board that enable the board to be steered

Leash: A cord that is attached to the back of the board, the other end of which wraps around the surfer's ankle

Nose : The forward tip of the board

Quiver: A surfer's collection of boards for different kinds of waves[15]

Rails: The side edges of the surfboard

Rocker: How concave the surface of the board is from nose to tail

Stringer: The line of wood that runs down the center of a board to hold its rigidity and add strength

Tail: The back end of the board

Wax: Specially formulated surf wax that is applied to upper surface of the board to increase the friction so the surfer's feet do not slip off the board

Leggie: A legrope or leash. The cord that connects your ankle to the tail of surfboard so it isn't washed away when you wipe out. Made of lightweight urethane and available in varying sizes. With thicker ones for big waves and thinner ones for small waves.

Thruster: A three-finned surfboard originally invented back in 1980 by Australian surfer Simon Anderson. It is nowadays the most popular fin design for modern surfboards.

 

The riding of waves has likely existed since humans began swimming in the ocean. In this sense, bodysurfing is the oldest type of wave-catching. Undoubtedly ancient sailors learned how to ride wave energy on many styles of early boats. Archaeological evidence even suggests that ancient cultures of Peru surfed on reed watercraft for fishing and recreation up to five thousand years ago. However, standing up on what is now called a surfboard is a relatively recent innovation developed by the Polynesians. The influences for modern surfing can be directly traced to the surfers of pre-contact Hawaii.

 

Peru

 

Caballito de totora

 

Chimú vessel representing a fisherman on a caballito de totora (1100–1400 CE)

Archaeologists have found that the practice of riding a vessel with a wave was utilized since the pre-Inca cultures around three to five thousand years ago.[1][2] The Moche culture used the caballito de totora (little horse of totora), with archaeological evidence showing its use around 200 CE.[3]

 

An early description of the Inca surfing was documented by Jesuit missionary José de Acosta in his 1590 publication Historia natural y moral de las Indias, writing:[4]

 

It is true to see them go fishing in Callao de Lima, was for me a thing of great recreation, because there were many and each one in a balsilla caballero, or sitting stubbornly cutting the waves of the sea, which is rough where they fish, they looked like the Tritons, or Neptunes, who paint upon the water.

To this day Caballitos de Totora are still used by local fishermen and can also be ridden by tourists for recreational purposes.

 

West Africa

West Africans (e.g., Ghana, Ivory Coast, Liberia, Senegal) and western Central Africans (e.g., Cameroon) independently developed the skill of surfing.[5] Amid the 1640s CE, Michael Hemmersam provided an account of surfing in the Gold Coast: “the parents ‘tie their children to boards and throw them into the water.’”[5] In 1679 CE, Barbot provided an account of surfing among Elmina children in Ghana: “children at Elmina learned “to swim, on bits of boards, or small bundles of rushes, fasten’d under their stomachs, which is a good diversion to the spectators.”[5] James Alexander provided an account of surfing in Accra, Ghana in 1834 CE: “From the beach, meanwhile, might be seen boys swimming into the sea, with light boards under their stomachs. They waited for a surf; and came rolling like a cloud on top of it. But I was told that sharks occasionally dart in behind the rocks and ‘yam’ them.”[5] Thomas Hutchinson provided an account of surfing in southern Cameroon in 1861: “Fishermen rode small dugouts ‘no more than six feet in length, fourteen to sixteen inches in width, and from four to six inches in depth.’”[5]

 

Polynesia

The art of surfing, known as heʻe nalu (literally, wave sliding)[6] in the Hawaiian language, was recorded in his journal by Joseph Banks aboard HMS Endeavour during the first voyage of James Cook, during the ship's stay in Tahiti in 1769:

 

...their cheif [sic] amusement was carried on by the stern of an old canoe, with this before them they swam out as far as the outermost breach, then one or two would get into it and opposing the blunt end to the breaking wave were hurried in with incredible swiftness. Sometimes they were carried almost ashore...[7]

 

Kahaluʻu Bay was the site of an ancient surfing temple.

Surfing was a central part of ancient Polynesian culture and predates European contact. The chief (Ali'i) was traditionally the most skilled wave rider in the community with the best board made from the best wood. The ruling class had the best beaches and the best boards, and the commoners were not allowed on the same beaches, but they could gain prestige by their ability to ride the surf on their boards.

 

In Tahiti and Samoa, surfing was a popular pastime that was often used as part of warriors' training. Warriors often paddled to surf breaks and were recorded in print by early European historians as spending many hours bravely paddling head-on into large surf and riding waves. Canoes often accompanied surfing parties and the men would often swap between canoeing and paddling boards, and then catch fish after their recreational activities. In Hawai'i, surfing became ingrained into the very fabric of Hawaii'an religion and culture.

 

The sport was also recorded in print by other European residents and visitors who wrote about and photographed Samoans surfing on planks and single canoe hulls; Samoans referred to surf riding as fa'ase'e or se'egalu. Edward Treager also confirmed Samoan terminology for surfing and surfboards in Samoa. Oral tradition confirms that surfing was also practiced in Tonga, where the late king Taufa'ahau Tupou IV became an expert surfer in his youth.[8] Matt Warshaw, however, says the King began to surf in the 1960s on a board given him by Duke Kahanamoku.[9]

 

Ancient Hawaii

Hawaiians referred to this art as heʻe nalu which translates into English as "wave sliding." The art began before entering the mysterious ocean as the Hawaiians prayed to the gods for protection and strength to undertake the powerful mystifying ocean. If the ocean was tamed, frustrated surfers would call upon the kahuna (priest), who would aid them in a surfing prayer asking the gods to deliver great surf. Prior to entering the ocean, the priest would also aid the surfers (mainly of the upper class) in undertaking the spiritual ceremony of constructing a surfboard.

 

Hawaiians would carefully select one of three types of trees. The trees included the koa (Acacia koa), ʻulu (Artocarpus altilis), and wiliwili (Erythrina sandwicensis) trees. Once selected, the surfer would dig the tree out and place fish in the hole as an offering to the gods. Selected craftsmen of the community were then hired to shape, stain, and prepare the board for the surfer. There were three primary shapes: the ʻolo, kikoʻo, and the alaia. The ʻolo is thick in the middle and gradually gets thinner towards the edges. The kikoʻo ranges in length from 370 to 550 cm (12 to 18 ft) and requires great skill to maneuver. The alaia board is around 275 cm (9 ft) long and requires great skill to ride and master. Aside from the preparatory stages prior to entering the water, the most skilled surfers were often of the upper class including chiefs and warriors that surfed amongst the best waves on the island. These upper-class Hawaiians gained respect through their enduring ability to master the waves and this art the Hawaiians referred to as surfing.[10] Some ancient sites still popular today include Kahaluʻu Bay and Holualoa Bay.[11]

 

Post-contact Hawaii

After contact with the Western World Hawaiian culture was forced to change. While Europeans were preoccupied with exploring and later colonizing the Pacific, they defined the islands as specks of land in a faraway sea.[12] Western diseases spread and colonization began, plantations were built, and immigration started. Local Hawaiians, mixed with imported workers from Asia, were put to work on sugar plantations and Protestant missionaries attempted to turn the population from their traditional beliefs into Christians. Along with the suppression of traditional culture was the suppression of surfing, often viewed as frivolous.

 

It was not until Waikiki became a tourist destination that surfing began a resurgence in popularity.[when?] Particularly wealthy Americans came to the beach and saw the locals occasionally surfing what had long been an established surf break, Waikiki, and wanted to try it. Mark Twain attempted it but failed in 1866. Jack London tried it while visiting, then chronicled it enthusiastically in an essay entitled "A Royal Sport" published in October 1907. In 1908 Alexander Hume Ford founded the Outrigger Canoe and Surfing Club the first modern organization developed to promote surfing broadly, although it was de facto whites-only and women weren't admitted until 1926. Local Hawaiians started their own club in 1911 called Hui Nalu, meaning "Club of the Waves". But the first surf icons who gained widespread recognition, George Freeth and Duke Kahanamoku, became famous for practicing their traditional sport and helped spread it from Waikiki to around the world.

 

As the news of this new sport began to spread, locals in Waikiki began giving lessons and demonstrations for tourists. This was the basis of the Waikiki Beach Boys, a loose group of mostly native Hawaiians who hung out at the beach, surfed daily, and taught wealthy haole tourists how to ride waves. This was also known as the Hawaiian boarder-land, where white hegemony was uncertain and Natives inverted dominant social categories.[12] A borderland is a place where differences converge and social norms are often fluid. Because state-sanctioned authority is often absent from the borderlands, unique social and cultural identities are formed there. This was the foundation of a continual element of surf culture, repeated around the globe innumerable times and continuing to this day: people who, for at least a time, dedicate most of their daily lives to living on or around the beach and surfing as much as they can. These groups in Hawaii, and following in Australia, California, laid the foundation for modern surf culture around the world.[12]

 

North America

See also: Surfing in the United States

In July 1885, three teenage Hawaiian princes took a break from their boarding school, St. Mathew's Hall in San Mateo, and came to cool off in Santa Cruz, California. There, David Kawananakoa, Edward Keliʻiahonui, and Jonah Kūhiō Kalaniana'ole surfed the mouth of the San Lorenzo River on custom-shaped redwood boards, according to surf historians Kim Stoner and Geoff Dunn.[13] In 1907 George Freeth traveled to California from Hawaii to demonstrate surfboard riding as a publicity stunt to promote Abbot Kinney's resort in Venice, Venice of America. Later that year, Henry Huntington, who gave his name to Huntington Beach, hired Freeth as a lifeguard and to give surfing demonstrations to promote the city of Redondo Beach. Freeth surfed at the Huntington Beach pier for its rededication in 1914. In 1917 Freeth moved to San Diego to work as a swimming instructor at the San Diego Rowing Club. He later worked as a lifeguard at Coronado and Ocean Beach where he also gave surfing exhibitions.[14]

 

Surfing on the East Coast of the United States began in Wrightsville Beach, North Carolina in 1909 when Burke Haywood Bridgers and a colony of surfers introduced surfing to the East Coast.[15] The State of North Carolina honored Burke Haywood Bridgers and the colony of surfers by placing a North Carolina Highway Marker for PIONEER EAST COAST SURFING on Wrightsville Beach and designated Wrightsville Beach as the birthplace of surfing in North Carolina in 2015.[16] North Carolina has the greater weight of published verifiable accurate evidence and impacts a broader geographical area when compared to other east coast states.[17] Burke Haywood Bridgers and the colony of surfers activities are among the earliest appearances of surfboards in the Atlantic Ocean.[18] The early twentieth-century surfers proved that surfing migrated from Hawaii to California and North Carolina about the same time, then Florida. The Wrightsville Beach Museum Waterman Hall of Fame honors, recognizes, and inducts community members for their contributions to the island's watersport culture.

 

Surf Culture Epicenters

For over a century now intrepid North American surfers have explored and ridden innumerable rugged and unnamed waves all over the vast North American coastline, yet distinct surf cultures tend to form around special small areas of particularly consistent good surf. The most archetypal and original of these is Malibu (both before and after Gidget). Not only is Malibu a rare world-class wave, but being adjacent to Hollywood it became the stereotype of Southern Californian surfing culture for the rest of the United States and the world. As Waikiki represented Hawaii, so Malibu represented California in the popular mindset. Both wave's quality remains intact to this day, but their local culture has gone through many shifts. Great surf epicenters often find their original surf culture quickly overrun by outside popularity, sometimes repeatedly.

 

Generally there are nine broadly defined continental regions, based on similar conditions: Alaskan, Cascadian, Northern California, Southern California, the Great Lakes, the Gulf Coast, East Coast of Florida, Georgia and the Carolinas, the North East, and Puerto Rico. Usually Hawaii is considered a separate entity from North America, subdivided by island and region. In professional surfing US mainlanders often use the American flag whereas Hawaiians (of any race) use the Hawaiian state flag.

 

Australian surfing

See also: Surfing in Australia

In 1910, Tommy Walker returned to Manly Beach, Sydney, with a 300 cm (10 ft) surfboard "bought at Waikiki Beach, Hawaii, for two dollars."[19] Walker became an expert rider and in 1912 gave several exhibitions in Sydney.[20]

 

Surfboard riding received national exposure with the exhibitions by Hawaiian Duke Kahanamoku in the summer of 1914-1915 at several Sydney beaches. As a current Olympic sprint champion, Kahanamoku was invited to tour the Eastern states for an extensive series of swimming carnivals and at his first appearance in the Domain Pool, Sydney, smashed his previous world record for 100 yards by a full second.[21] Following the first exhibition at Freshwater on 24 December 1914,[22] in the New Year Kahanamoku demonstrated his skill at Freshwater and Manly,[23] followed by appearances at Dee Why[24] and Cronulla.[25]

 

Duke Kahanamoku's board is now on display in the Freshwater Surf Life Saving Club, Sydney, Australia.[26]

 

Great Britain

Main article: Surfing in the United Kingdom

In 1890, the pioneer in agricultural education John Wrightson reputedly became the first British surfer at Bridlington in Yorkshire when instructed by two Hawaiian students, Princes David Kahalepouli Kawanaankoa Piikoi and Jonah Kuhio Kalanianaole Pikkoi, studying at his college.[27][28][29]

 

Modern surfing

Around the start of the 20th century, Hawaiians living close to Waikiki began to revive surfing, and soon re-established surfing as a sport. The revival is linked to real estate development and efforts to boost tourism.[30] The beach was historically a place where haole and Hawaiian worlds collided and violence was sometimes a substitute for mutual understanding.[12] Duke Kahanamoku, "Ambassador of Aloha," Olympic medalist, and avid waterman, helped expose surfing to the world. Kahanamoku's role was later memorialized by a 2002 first class letter rate postage stamp of the United States Postal Service.[31] Author Jack London wrote about the sport after having attempted surfing on his visit to the islands. Surfing progressed tremendously in the 20th century, through innovations in board design and ever-increasing public exposure.

 

Surfing's development and culture was centered primarily in three locations: Hawaii, Australia, and California, although the first footage of surfing in the UK was in 1929 by Louis Rosenberg and a number of friends after being fascinated by watching some Australian surfers. In 1959 the release of the film Gidget, based on the life of surfer Kathy Kohner-Zuckerman, boosted the sport's popularity immensely, moving surfing from an underground culture into a national fad and packing many surf breaks with sudden and previously unheard of crowds. B-movies and surf music such as the Beach Boys and Surfaris based on surfing and Southern California beach culture (Beach Party films) as it exploded, formed most of the world's first ideas of surfing and surfers.[citation needed] This conception was revised again in the 1980s, with newer mainstream portrayals of surfers represented by characters like Jeff Spicoli from Fast Times at Ridgemont High.

  

Surfing at Ormond Beach in Oxnard, California, in 1975

The anonymous sleeve notes on the 1962 album Surfin' Safari, the first album to be released on the Capitol label by The Beach Boys, include a rather tongue-in-cheek description of the sport of surfing thus:

 

"For those not familiar with the latest craze to invade the sun-drenched Pacific coast of Southern California, here is a definition of "surfing" - a water sport in which the participant stands on a floating slab of wood, resembling an ironing board in both size and shape, and attempts to remain perpendicular while being hurtled toward the shore at a rather frightening rate of speed on the crest of a huge wave (especially recommended for teen-agers and all others without the slightest regard for either life or limb)."

Regardless of its usually erroneous portrayal in the media, true surfing culture continued to evolve quietly by itself, changing decade by decade. From the 1960s fad years to the creation and evolution of the short board in the late 60s and early 70s to the performance hotdogging of the neon-drenched 1980s and the epic professional surfing of the 1990s (typified by Kelly Slater, the "Michael Jordan of Surfing"). In 1975, professional contests started.[32] That year Margo Oberg became the first female professional surfer.[32]

 

Surfing documentaries have been one of the main ways in which surfing culture grows and replenishes itself, not just as a sport but as an art form, the style and quality of surf films have often tracked well the evolution of the sport.

 

Professional surfing

Defining the scope of professional surfing is difficult, because like in many extreme sports, there is more than one model for what constitutes a professional. There are three main contemporary modes of making money purely as an active surfer: sponsorship, surf contests, and social media influence. Most often all three go together, but sometimes well-known professionals excel in only one.

 

If a professional surfer is someone who makes money from surfing (not including teaching), then the history of professional surfing dates to perhaps 1959 when the first West Coast Surfing Championships was held in Huntington Beach, California. Previously there had been innumerable amateur competitions, from the ancient Hawaiians themselves who were known to wager on the outcomes, to multiple iterations of surf competition as some form of race (commonly starting from shore, paddling to a buoy, then catching a wave back to shore).

 

In 1961 the United States Surfing Association (USSA) was founded, arguably the first proto-professional surfing contest organization. This was also about the time when surfing switched from core action: simply riding a quality wave, to a more style-oriented endeavor where turns, tricks, style, and artistry began to be important. Dynamic moves, such as nose-riding, top turns, and cut-backs were becoming even more important than catching the best wave and riding it for the longest possible time, which had previously been the primary goal, and seemed self-evident to earlier surfers.

 

Through numerous iterations of the surf contest and small sponsorships, very few people ever made a living from surfing alone (by not teaching or producing signature model boards or clothing) until the 1970s. As described in the documentary Bustin' Down the Door much of the prestige and money to be made from contest surfing resided in Hawaii, specifically, the increasingly important epicenter of worldwide performance-surfing: the North Shore of Oahu. But when Australians and South Africans showed up to join the Californians who had been migrating there in waves for nearly 20 years, multiple tensions arose between not only the Americans vs international surfers, but even more powerfully between the local Hawaiians and the haoles generally.

 

Into the 1980s surfing saw its second boost of wider popular recognition (the first being from Gidget) with new neon colors, increasing shortboard performance, more professional surfers, and a number of surf brands becoming trendy beyond surfing, such as Town & Country Surf Designs and Body Glove. The pro surfers of the 1980s were able to make more money, get more exposure, and generally survive longer with no job other than contest surfing and sponsorship.

 

In the last few decades there are generally less than 60 men and 30 women who qualify for the highest level of the surf league each year in its modern form, the WSL. There are thousands more surfers competing in various smaller surf contests held continually around the world, the majority of them being for groms (young participants). In the last half century of competitive surfing, nearly all professionals have learned to surf as children and were essentially prodigies, as in most modern professional sports.

 

In 1920, Duke Kahanamoku, the "Father of Modern Surfing", proposed that the sport be included in the Olympics. Surfing was to be a part of the Olympics for the first time ever in the 2020 Tokyo Olympics, allowing athletes from around the world to show their skills in the sport. Before surfing could make its Olympic debut, the COVID-19 pandemic caused the 2020 Tokyo Olympic Games to be cancelled and then rescheduled for the year 2021. Surfing is set to appear in the 2021 Olympics with several members of the WSL as well as other amateur surfers for the first time ever at Tsurigasaki Beach in Chiba Japan.[33]

  

A surfer dropping in

Technological innovations in surfing

Surfing has been an internationally co-developed sport since its early spread beyond Hawaii, and has been highly influenced by (and generally welcoming of) new technology. There are no standards or committees to rule surfboard design or progression. Change has been rampant. Surfers generally pick styles and materials based on performance, feeling, and price. Surfboard shapers can be global name-brand professionals, local artisans, or even backyard amateurs. Unlike many other sports, the high variability and subtle performance differences in the main apparatus, the surfboard, is fundamental to both the experience and history. While many other sports standardize their equipment, in surfing, diversity in craft-design played a huge part in its history and still ongoing culture.

 

Much of the last century of surf history has been defined by new eras of technology which often fundamentally changed the experience. Surfers themselves have often developed, altered, or anticipated new technology to grant increased access to previously unsurfed waves and places. And unlike many other sports, the secondary equipment became almost as important as the core surfboard, a prime example being the wetsuit. The worldwide history of surfing could easily be divided between pre-wetsuit and post-wetsuit, because it expanded the potential to surf places previously far too cold, which comprised a vast amount of un-surfed worldwide coastline. On a similar basis, surfing history could justifiably be divided between pre-polystyrene and post-polystyrene surfboards, or pre-fin and post-fin as the original Hawaiian boards did not have fins until Tom Blake added one in 1935. Technology has changed surfing repeatedly and dramatically throughout its modern development, generally making the sport more accessible, cheaper, easier, and raising the level of performance.

 

Much of this change has also come from the fact that surfing was originally, and for many decades into the modern era, primarily a tropical or summertime only warm water sport, and a developed-world sport, making its early range quite limited. But after the arrival of mass-produced fiberglass boards, quality wetsuits, offroad vehicles, and inexpensive international travel, surfing became accessible along many parts of the world's coasts which were previously unthinkable or unknown as surf spots. Travelers thereby introduced the sport and equipment to the local coastal peoples of even very remote places. By the 21st century, much of the worldwide coastline has been explored and local peoples surf in nearly every country with access to waves. Yet unlike many other aspects of human expansion, there remain surf breaks as yet never ridden by humans, often in remote or treacherous corners of the globe, politically unstable areas, or around uninhabited islands, many which might yet reveal great surf spots in the future.

  

A quiver of surfboards

The Short Board Revolution

The ancient Hawaiians had mainly three types of board: Olo, Alaia, and Paipo. The Olo was 4.5 to 6.096 meters (15 to 20 ft) long and solid wood. They were very difficult to make and reserved for the upper classes. The Alai was only 1.82 or 2.13 meters (6 or 7 ft) long and usually much thinner. The Paipo was even smaller and similar to a modern bodyboard. None of these had a fin.

 

Throughout the first half of the 20th century nearly all modern surfboards were longboards, generally 2.74 meters (9 ft) or longer, although after the 1930s they began to shift away from being solid dense wood and towards lighter materials like balsa wood, and eventually various forms of polystyrene, which still dominate to this day.

 

Throughout the decades, shapers had occasionally made smaller boards, often as novelties, experiments, or specifically designed for small-statured people, but the popularity of those designs was slow to rise. During the surfboard production boom of the 1960s, the predominantly male shapers would sometimes construct specifically smaller boards for girls (who are often lighter and shorter, affecting weight/length requirements for paddling). Yet often they ended up surfing those small boards themselves because the style of surfing was different and mid-wave turns were growing in popularity, more easily done on shorter boards.

 

A fundamental reason for longer, thicker, more buoyant surfboards generally is they paddle faster, and paddle-speed is crucial to wave catching. But in the 1960s faster waves were becoming more popular, waves with narrower take off zones, requiring more skill to drop in. If the surfer could catch a fast wave, then a shorter board was inherently more maneuverable (and by extension more fun).

 

By the early 1970s, shorter boards began to rise dramatically in popularity, not just as novelties but as fulltime craft, so design innovation was not far behind. The number of fins and their location was experimented with. Various nose and tail shapes were tried. Then, by the 1980s, the styles were refined and coalescing into the modern shortboard just as the second large burst of broader surf-culture popularity within the mainstream was occurring. The 3-fin, 1.82 meters (6-ft-tall)"thruster" shortboard began to take over as the most popular design. A generally narrow board with rather small variance in design was being mass-produced. It nearly always has three fins, a pointed nose, a squash tail, and was approximately the height of the rider.

 

This basic style of board, with many small modifications, has been the dominant craft since the 1980s and is still the approximation of the modern professional surfboard. In 21st century professional surfing the common boards have slowly become shorter and wider, with a more rounded nose and sometimes 4-fins (very rarely 2-fins and never 1-fin), although non-professionals still regularly mix and match all those options based on personal taste.

 

Big wave surfing

Main article: Big wave surfing

Although the original Hawaiian surfers would ride large unbreaking ocean swells on their Olo boards, surfing a breaking wave larger than 4.5 to 6.1 meters (15–20 ft) was extremely challenging with pre-modern equipment, if it was attempted at all. But once board design began advancing rapidly in the 1950s and 1960s these larger and faster waves became more accessible. The first truly renowned big wave spot was Oahu's Waimea Bay. As the North Shore of Oahu was being explored for all its various breaks, Waimea was seen as too fast, brutal, and difficult. As detailed in the movie Riding Giants the first documented successful attempt was in October 1957. Once Waimea was finally surfed, it spawned the search for other giant waves around the world, and a devotional subset of surfers who specifically desired to surf very large waves. By the 1990s there were numerous giant waves being surfed all over the world, some regularly reaching the 12.2, 15.2, even 18.3 meters (40-, 50-, 60-ft) range. Big wave surfing bifurcated into two main branches: paddle-in and tow-in. Some waves are so big and quick it is nearly impossible to paddle fast enough to catch them, so surfers started towing behind boats and PWCs in order to catch the wave.

 

Style versus performance

"What is the purpose of surfing?" has long been philosophically debated in and out of surf culture. Often the entire endeavor has been viewed in the popular media as a waste of time, or the occupation of slackers. For the most part, surfing is agreed to be purely recreational, as it did not develop from, or turn into, a useful mode of daily transportation (as opposed to skiing or skateboarding, which can be both). Therefore in judging and appreciating surfing there has always been varying opinions about what is necessary, stylish, extravagant, and/or functional.

 

The variety and size of waves varies tremendously, as does surf craft, and to some degree even the medium. Harnessing the momentum of a wave for travel is the loosest definition of surfing, so in popular culture, the term is often applied to many forms of expanded "surfing". Particularly "surfing the web" and "couch surfing" common examples. But also characters like The Silver Surfer have taken the notion of surfing into science fiction.

 

There are also those who view surfing in a religious context. Certainly for the ancient Hawaiians, this component was important because the ocean was viewed as a deity. Yet also in modern surfing it is common for surfing to refer to it as some form of church or mass.

 

Surfing's impact on popular culture

Comparatively small and localized surfing cultures have repeatedly generated surprisingly large influence upon popular culture, particularly in the United States of America and Australia, as well as upon the global consciousness of surfing as a form of recreation. Since the expansion of surfing in the mid-20th century, there have been numerous coastal towns that were situated near good surf breaks, whose citizens did not yet know about modern surfing, and so did not even realize it was a rare commodity.

 

In America and Australia, the culture of surfing has influenced popular culture in periodic fads, starting with novels, movies, and the early-1960s TV show, Gidget. Gidget is often given credit for popularizing surfing as a "slightly strange and hedonistic lifestyle".[34] In film specifically, the surfing image has been so popular that it inspired an entire “beach party/surf film genre”.[35] The attention that surfing has received in popular culture has waxed and waned, much like other niche sports.

 

Another area of popular culture where surfing has had significant influence is popular music. As many scholars recognize, a large part of surfing’s popularity is from the positively connoted image of “beach parties, rich tans, loose clothing, and surf-ready cars"; in other words, there is "more to surfing than the sea”.[34] This image is very well suited to be represented in popular music, which is why so many popular teen anthems are based on the surfing craze.[34] The Beach Boys, a group whose songs frequently involved “an endless summer filled with surfing, cruising, and beachcombing,” is only one such example.[34] In the first half of the 1960s especially, popular music was dominated by exuberant music featuring the surf craze ("surf rock").[36] Another example is Katy Perry’s Billboard #1 hit song “California Gurls,” featuring Snoop Dogg[37] released in 2010, which highlights the same beachside lifestyle first popularized in the 1960s.

 

Fashions developed within surf culture have had a large worldwide impact numerous times from the 1960s to the present. A number of large clothing brands began as surfing brands, including but not limited to: OP, Stussy, Billabong, Quicksilver, Roxy, Hurley, O'Neill, Ripcurl, RVCA, Vans, Volcom, Reef, and Da Kine. One of the largest influences is probably the worldwide adoption of boardshorts as swim gear for men.

 

Alternatives to wind-generated waves

Since their invention, surfers have sometimes used wave pools to attempt surfing, but generally, the waves were too small and not well-formed enough for an enjoyable experience. The 1987 movie North Shore started the protagonist in an Arizona wave pool, then going on to Hawaii to try his luck. Both in and out of the movie this was considered basically a joke. But more recently, multiple attempts have been made to construct wave pools specifically designed for surfing. As of 2023 there are only a few around the world open to the public, but there are numerous in development. 2018 was the first year a professional surfing contest was held at a wave pool, specifically: Kelly Slater's Surf Ranch.[38]

 

Wakeboarding is a popular type of surfing done behind a boat's wake. There are also sometimes standing waves in rivers at high flow which can be surfable. At certain times of year on large rivers, tidal bores are surfable. People have also surfed alongside large cargo ships as their wakes roll into shallower water, and a few people have even surfed the waves caused by calving glaciers. The Wave Bristol opened in The UK as an inland artificial surf site.[39]

 

Surfing is a surface water sport in which an individual, a surfer (or two in tandem surfing), uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suitable for surfing are primarily found on ocean shores, but can also be found as standing waves in the open ocean, in lakes, in rivers in the form of a tidal bore, or wave pools.

 

The term surfing refers to a person riding a wave using a board, regardless of the stance. There are several types of boards. The Moche of Peru would often surf on reed craft, while the native peoples of the Pacific surfed waves on alaia, paipo, and other such water craft. Ancient cultures often surfed on their belly and knees, while the modern-day definition of surfing most often refers to a surfer riding a wave standing on a surfboard; this is also referred to as stand-up surfing.

 

Another prominent form of surfing is body boarding, where a surfer rides the wave on a bodyboard, either lying on their belly, drop knee (one foot and one knee on the board), or sometimes even standing up on a body board. Other types of surfing include knee boarding, surf matting (riding inflatable mats) and using foils. Body surfing, in which the wave is caught and ridden using the surfer's own body rather than a board, is very common and is considered by some surfers to be the purest form of surfing. The closest form of body surfing using a board is a handboard which normally has one strap over it to fit on one hand. Surfers who body board, body surf, or handboard feel more drag as they move through the water than stand up surfers do. This holds body surfers into a more turbulent part of the wave (often completely submerged by whitewater). In contrast, surfers who instead ride a hydrofoil feel substantially less drag and may ride unbroken waves in the open ocean.

 

Three major subdivisions within stand-up surfing are stand-up paddling, long boarding and short boarding with several major differences including the board design and length, the riding style and the kind of wave that is ridden.

 

In tow-in surfing (most often, but not exclusively, associated with big wave surfing), a motorized water vehicle such as a personal watercraft, tows the surfer into the wave front, helping the surfer match a large wave's speed, which is generally a higher speed than a self-propelled surfer can produce. Surfing-related sports such as paddle boarding and sea kayaking that are self-propelled by hand paddles do not require waves, and other derivative sports such as kite surfing and windsurfing rely primarily on wind for power, yet all of these platforms may also be used to ride waves. Recently with the use of V-drive boats,[clarification needed] Wakesurfing, in which one surfs on the wake of a boat, has emerged.[citation needed] As of 2023, the Guinness Book of World Records recognized a 26.2 m (86 ft) wave ride by Sebastian Steudtner at Nazaré, Portugal as the largest wave ever surfed.[1]

 

During the winter season in the northern hemisphere, the North Shore of Oahu, the third-largest island of Hawaii, is known for having some of the best waves in the world. Surfers from around the world flock to breaks like Backdoor, Waimea Bay, and Pipeline. However, there are still many popular surf spots around the world: Teahupo'o, located off the coast of Tahiti; Mavericks, California, United States; Cloudbreak, Tavarua Island, Fiji; Superbank, Gold Coast, Australia.[2]

 

In 2016 surfing was added by the International Olympic Committee (IOC) as an Olympic sport to begin at the 2020 Summer Olympics in Japan.[3] The first gold medalists of the Tokyo 2020 surfing men and women's competitions were, respectively, the Brazilian Ítalo Ferreira and the American from Hawaii, Carissa Moore.[4][5]

 

Origins and history

Main article: History of surfing

Peru

 

Caballitos de totora, reed watercraft used by fishermen for the past 3000 years at Huanchaco, Peru, known for its surf breaks

About three to five thousand years ago, cultures in ancient Peru fished in kayak-like watercraft (mochica) made of reeds that the fishermen surfed back to shore.[6][7] The Moche culture used the caballito de totora (little horse of totora), with archaeological evidence showing its use around 200 CE.[8] An early description of the Inca surfing in Callao was documented by Jesuit missionary José de Acosta in his 1590 publication Historia natural y moral de las Indias, writing:[9]

 

It is true to see them go fishing in Callao de Lima, was for me a thing of great recreation, because there were many and each one in a balsilla caballero, or sitting stubbornly cutting the waves of the sea, which is rough where they fish, they looked like the Tritons, or Neptunes, who paint upon the water.

Polynesia

 

Hawaiians surfing, 1858

In Polynesian culture, surfing was an important activity. Modern surfing as we know it today is thought to have originated in Hawaii. The history of surfing dates to c. AD 400 in Polynesia, where Polynesians began to make their way to the Hawaiian Islands from Tahiti and the Marquesas Islands. They brought many of their customs with them including playing in the surf on Paipo (belly/body) boards. It was in Hawaii that the art of standing and surfing upright on boards was invented.[10]

 

Various European explorers witnessed surfing in Polynesia. Surfing may have been observed by British explorers at Tahiti in 1767. Samuel Wallis and the crew members of HMS Dolphin were the first Britons to visit the island in June of that year. Another candidate is the botanist Joseph Banks[11] who was part of the first voyage of James Cook on HMS Endeavour, arriving on Tahiti on 10 April 1769. Lieutenant James King was the first person to write about the art of surfing on Hawaii, when he was completing the journals of Captain James Cook (upon Cook's death in 1779).

 

In Herman Melville's 1849 novel Mardi, based on his experiences in Polynesia earlier that decade, the narrator describes the "Rare Sport at Ohonoo" (title of chap. 90): “For this sport, a surf-board is indispensable: some five feet in length; the width of a man's body; convex on both sides; highly polished; and rounded at the ends. It is held in high estimation; invariably oiled after use; and hung up conspicuously in the dwelling of the owner.”[12] When Mark Twain visited Hawaii in 1866 he wrote, "In one place, we came upon a large company of naked natives of both sexes and all ages, amusing themselves with the national pastime of surf-bathing."[13]

 

References to surf riding on planks and single canoe hulls are also verified for pre-contact Samoa, where surfing was called fa'ase'e or se'egalu (see Augustin Krämer, The Samoa Islands[14]), and Tonga, far pre-dating the practice of surfing by Hawaiians and eastern Polynesians by over a thousand years.

 

West Africa

West Africans (e.g., Ghana, Ivory Coast, Liberia, Senegal) and western Central Africans (e.g., Cameroon) independently developed the skill of surfing.[15] Amid the 1640s CE, Michael Hemmersam provided an account of surfing in the Gold Coast: “the parents ‘tie their children to boards and throw them into the water.’”[15] In 1679 CE, Barbot provided an account of surfing among Elmina children in Ghana: “children at Elmina learned “to swim, on bits of boards, or small bundles of rushes, fasten’d under their stomachs, which is a good diversion to the spectators.”[15] James Alexander provided an account of surfing in Accra, Ghana in 1834 CE: “From the beach, meanwhile, might be seen boys swimming into the sea, with light boards under their stomachs. They waited for a surf; and came rolling like a cloud on top of it. But I was told that sharks occasionally dart in behind the rocks and ‘yam’ them.”[15] Thomas Hutchinson provided an account of surfing in southern Cameroon in 1861: “Fishermen rode small dugouts ‘no more than six feet in length, fourteen to sixteen inches in width, and from four to six inches in depth.’”[15]

 

California

 

A woman holding her surfboard about to surf in Morro Bay, California

In July 1885, three teenage Hawaiian princes took a break from their boarding school, St. Matthew's Hall in San Mateo, and came to cool off in Santa Cruz, California. There, David Kawānanakoa, Edward Keliʻiahonui and Jonah Kūhiō Kalanianaʻole surfed the mouth of the San Lorenzo River on custom-shaped redwood boards, according to surf historians Kim Stoner and Geoff Dunn.[16] In 1890, the pioneer in agricultural education John Wrightson reputedly became the first British surfer when instructed by two Hawaiian students at his college.[17][18][19]

 

George Freeth (1883–1919), of English and Native Hawaiian descent, is generally credited as the person who had done more than anyone else to renew interest in surfing at Waikiki in the early twentieth century after the sport had declined in popularity in Hawaii during the latter half of the nineteenth century.[20][21][22]

 

In 1907, the eclectic interests of land developer Abbot Kinney (founder of Venice of America, now Venice, California) helped bring Freeth to California. Freeth had sought the help of the Hawaii Promotion Committee (HPC) in Honolulu to sponsor him on a trip to California to give surfing exhibitions. The HPC arranged through their contacts in Los Angeles to secure a contract for Freeth to perform at Venice of America in July, 1907.[23] Later that year, land baron Henry E. Huntington brought surfing to Redondo Beach. Looking for a way to entice visitors to his own budding resort community south of Venice where he had heavily invested in real estate, he hired Freeth as a lifeguard and to give surfing exhibitions in front of the Hotel Redondo.[21] Another native Hawaiian, Duke Kahanamoku, spread surfing to both the U.S. and Australia, riding the waves after displaying the swimming prowess that won him Olympic gold medals in 1912 and 1920.[24]

 

Mary Ann Hawkins, inspired by Duke Kahanamoku's surfing during the late 1920s, developed a lifelong passion for surfing. In 1935, her family relocated to Santa Monica, providing her with opportunities to further immerse herself in surfing and paddleboarding.[25] On September 12, 1936, Hawkins achieved a historic milestone by winning California’s first women’s paddleboard race at the Santa Monica Breakwater. She continued to dominate the sport,[25] winning numerous competitions, including the women’s half-mile paddleboard race and the Venice Breakwater event in 1938, both held on the same day.

 

Hawkins was also a pioneer in tandem surfing, a discipline that highlights synchronized surfing between two individuals on a single board. She gained further recognition in 1939 when she performed exhibition paddleboarding and tandem surfing displays at various Southern California beaches, inspiring a new generation of women surfers. [25]

 

In January 1939, Hawkins was appointed head of the women’s auxiliary group of the Santa Monica Paddle Club and rose to vice president by January 1940.[25] Her surfing peers frequently lauded her achievements, with "Whitey" Harrison describing her as "the best tandem rider." Throughout her career, Hawkins exemplified grace and athleticism, leaving an indelible mark on the history of women’s surfing and paddleboarding.

 

In 1975, a professional tour started.[26] That year Margo Oberg became the first female professional surfer.[26]

 

Surf waves

See also: Ocean surface wave

 

Pipeline barrel at Pūpūkea, Hawaii

 

Surfer getting tubed at Sunset on the North Shore of Oahu

 

A large wave breaking at Mavericks

Swell is generated when the wind blows consistently over a large space of open water, called the wind's fetch. The size of a swell is determined by the strength of the wind, and the length of its fetch and duration. Because of these factors, the surf tends to be larger and more prevalent on coastlines exposed to large expanses of ocean traversed by intense low pressure systems.

 

Local wind conditions affect wave quality since the surface of a wave can become choppy in blustery conditions. Ideal conditions include a light to moderate "offshore" wind, because it blows into the front of the wave, making it a "barrel" or "tube" wave. Waves are left-handed and right-handed depending upon the breaking formation of the wave.

 

Waves are generally recognized by the surfaces over which they break.[27] For example, there are beach breaks, reef breaks and point breaks.

 

The most important influence on wave shape is the topography of the seabed directly behind and immediately beneath the breaking wave. Each break is different since each location's underwater topography is unique. At beach breaks, sandbanks change shape from week to week. Surf forecasting is aided by advances in information technology. Mathematical modeling graphically depicts the size and direction of swells around the globe.

 

Swell regularity varies across the globe and throughout the year. During winter, heavy swells are generated in the mid-latitudes, when the North and South polar fronts shift toward the Equator. The predominantly Westerly winds generate swells that advance Eastward, so waves tend to be largest on West coasts during winter months. However, an endless train of mid-latitude cyclones cause the isobars to become undulated, redirecting swells at regular intervals toward the tropics.

 

East coasts also receive heavy winter swells when low-pressure cells form in the sub-tropics, where slow moving highs inhibit their movement. These lows produce a shorter fetch than polar fronts, however, they can still generate heavy swells since their slower movement increases the duration of a particular wind direction. The variables of fetch and duration both influence how long wind acts over a wave as it travels since a wave reaching the end of a fetch behaves as if the wind died.

 

During summer, heavy swells are generated when cyclones form in the tropics. Tropical cyclones form over warm seas, so their occurrence is influenced by El Niño and La Niña cycles. Their movements are unpredictable.

 

Surf travel and some surf camps offer surfers access to remote, tropical locations, where tradewinds ensure offshore conditions. Since winter swells are generated by mid-latitude cyclones, their regularity coincides with the passage of these lows. Swells arrive in pulses, each lasting for a couple of days, with a few days between each swell.

 

The availability of free model data from the NOAA has allowed the creation of several surf forecasting websites.

 

Tube shape and speed

 

The geometry of tube shape can be represented as a ratio between length and width.

Tube shape is defined by length to width ratio. A perfectly cylindrical vortex has a ratio of 1:1. Other forms include:

 

Square: <1:1

Round: 1–2:1

Almond: >2:1

Peel or peeling off as a descriptive term for the quality of a break has been defined as "a fast, clean, evenly falling curl line, perfect for surfing, and usually found at pointbreaks."[28]

 

Tube speed is the rate of advance of the break along the length of the wave, and is the speed at which the surfer must move along the wave to keep up with the advance of the tube.[29] Tube speed can be described using the peel angle and wave celerity. Peel angle is the angle between the wave front and the horizontal projection of the point of break over time, which in a regular break is most easily represented by the line of white water left after the break. A break that closes out, or breaks all at once along its length, leaves white water parallel to the wave front, and has a peel angle of 0°. This is unsurfable as it would require infinite speed to progress along the face fast enough to keep up with the break. A break which advances along the wave face more slowly will leave a line of new white water at an angle to the line of the wave face.[29][30]

 

V

s

=

c

s

i

n

α

{\displaystyle V_{s}={\frac {c}{sin\alpha }}}[29]

Where:

 

V

s

=

{\displaystyle V_{s}=}velocity of surfer along the wave face

c

=

{\displaystyle c=}wave celerity (velocity in direction of propagation)

α

=

{\displaystyle \alpha =}peel angle

In most cases a peel angle less than 25° is too fast to surf.[29]

 

Fast: 30°

Medium: 45°

Slow: 60°

Wave intensity table

FastMediumSlow

SquareThe CobraTeahupooShark Island

RoundSpeedies, GnaralooBanzai Pipeline

AlmondLagundri Bay, SuperbankJeffreys Bay, Bells BeachAngourie Point

Wave intensity

The type of break depends on shoaling rate. Breaking waves can be classified as four basic types: spilling (ξb<0.4), plunging (0.4<ξb<2), collapsing (ξb>2) and surging (ξb>2), and which type occurs depends on the slope of the bottom.[29]

 

Waves suitable for surfing break as spilling or plunging types, and when they also have a suitable peel angle, their value for surfing is enhanced. Other factors such as wave height and period, and wind strength and direction can also influence steepness and intensity of the break, but the major influence on the type and shape of breaking waves is determined by the slope of the seabed before the break. The breaker type index and Iribarren number allow classification of breaker type as a function of wave steepness and seabed slope.[29]

 

Artificial reefs

The value of good surf in attracting surf tourism has prompted the construction of artificial reefs and sand bars. Artificial surfing reefs can be built with durable sandbags or concrete, and resemble a submerged breakwater. These artificial reefs not only provide a surfing location, but also dissipate wave energy and shelter the coastline from erosion. Ships such as Seli 1 that have accidentally stranded on sandy bottoms, can create sandbanks that give rise to good waves.[31]

 

An artificial reef known as Chevron Reef was constructed in El Segundo, California in hopes of creating a new surfing area. However, the reef failed to produce any quality waves and was removed in 2008. In Kovalam, South West India, an artificial reef has successfully provided the local community with a quality lefthander, stabilized coastal soil erosion, and provided good habitat for marine life.[32] ASR Ltd., a New Zealand-based company, constructed the Kovalam reef and is working on another reef in Boscombe, England.

 

Artificial waves

 

Surfing a stationary, artificial wave in Southern California

Even with artificial reefs in place, a tourist's vacation time may coincide with a "flat spell", when no waves are available. Completely artificial wave pools aim to solve that problem by controlling all the elements that go into creating perfect surf, however there are only a handful of wave pools that can simulate good surfing waves, owing primarily to construction and operation costs and potential liability. Most wave pools generate waves that are too small and lack the power necessary to surf. The Seagaia Ocean Dome, located in Miyazaki, Japan, was an example of a surfable wave pool. Able to generate waves with up to 3 m (10 ft) faces, the specialized pump held water in 20 vertical tanks positioned along the back edge of the pool. This allowed the waves to be directed as they approach the artificial sea floor. Lefts, Rights, and A-frames could be directed from this pump design providing for rippable surf and barrel rides. The Ocean Dome cost about $2 billion to build and was expensive to maintain.[33] The Ocean Dome was closed in 2007. In England, construction is nearing completion on the Wave,[34] situated near Bristol, which will enable people unable to get to the coast to enjoy the waves in a controlled environment, set in the heart of nature.

 

There are two main types of artificial waves that exist today. One being artificial or stationary waves which simulate a moving, breaking wave by pumping a layer of water against a smooth structure mimicking the shape of a breaking wave. Because of the velocity of the rushing water, the wave and the surfer can remain stationary while the water rushes by under the surfboard. Artificial waves of this kind provide the opportunity

glossary.ametsoc.org/wiki/Chinook_arch

Parapodial lobes closed, and opened widely exposing their upper surface with dendritic digestive gland, and the dorsum of the body. Opaque white mark on rims of lobes.

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

PDF available at www.researchgate.net/publication/352311905_Elysia_viridis....

 

Elysia viridis (Montagu, 1804).

Authors: Ian F. Smith (text) and Malcolm Storey (shore work and photography).

 

Current taxonomy; World Register of Marine Species www.marinespecies.org/aphia.php?p=taxdetails&id=139686

Synonyms: Laplysia viridis Montagu, 1804.

 

GLOSSARY below.

 

Description

The smooth body, lacking tubercles, has a usual maximum length in Britain of 45 mm with the large head occupying the anterior 25% (fig. 1 flic.kr/p/2kZtvp3 ). The rear 75% is flanked by large parapodial lobes which can be closed over the body or opened widely (fig. 2 flic.kr/p/2kZqFxK ) exposing their upper surface and dorsum of the body.

A deep groove separates the head laterally and ventrally from the rest of the body (fig. 3 flic.kr/p/2kZpzf9 ). The head has a pair of tightly enrolled rhinophores (fig. 4 flic.kr/p/2kZv2Xr ) which start to appear when the body is about 3 mm long. There are no oral tentacles. The anterior of the head has a central cleft (fig. 5 flic.kr/p/2kZtvf5 ). Laterally behind each rhinophore there is a small black eye in a pale area (fig. 3 flic.kr/p/2kZpzf9 ) bordered by freckles of white pigment which continue at varying densities onto the rhinophores. The radula is reduced to a single row of teeth adapted solely for slitting and cutting (Taylor, 1968). The most usual ground colour of the body is some shade of brown or olive, often with a green or red cast. Those feeding on Codium are usually dull olive green (fig. 6 flic.kr/p/2kZkX1n ) but colours can include bright green (figs. 2 flic.kr/p/2kZqFxK & 8 flic.kr/p/2kZqFe3 ), red-brown (fig. 1 flic.kr/p/2kZtvp3 ), orange and cream (fig. 5 flic.kr/p/2kZtvf5 ). They are variably speckled with glistening blue, turquoise or green (figs. 7 flic.kr/p/2kZkWPv , 9 flic.kr/p/2kZpyXR & 10 flic.kr/p/2kZv2Ja ). When the parapodial lobes are spread open, their inner surfaces and dorsum of the body are often green with a visible leaf-like (figs. 2 flic.kr/p/2kZqFxK & 8 flic.kr/p/2kZqFe3 ) dendritic digestive gland. The rim of each lobe usually has an opaque white mark (fig. 2 flic.kr/p/2kZqFxK ), often with several other less distinct whitish marks (fig. 1 flic.kr/p/2kZtvp3 ).

The anterior of the foot is rounded and expanded (fig. 12 flic.kr/p/2kZv2Gr ) but rarely extended into distinct curved propodial tentacles as drawn by Meyer & Möbius, (1865 in Thompson, 1976). The translucent pale sole shows the variable colour of the digestive gland and other viscera (fig. 11 flic.kr/p/2kZkWJW ) and often has many white, pinkish flakes and/or fine brown pigment specks (figs 3 flic.kr/p/2kZpzf9 & 12 flic.kr/p/2kZv2Gr ).

 

Key identification features

E. viridis

1) Large parapodial lobes (fig. 2 flic.kr/p/2kZqFxK ), start to form before 3 mm body length (fig. 4 flic.kr/p/2kZv2Xr ).

2) Speckled with glistening blue, green or turquoise (figs. 9 flic.kr/p/2kZpyXR & 10 flic.kr/p/2kZv2Ja ).

3) No oral tentacles or enrolled oral veil.

4) Usual maximum length in Britain 45 mm.

 

Similar species

Aplysia punctata (Cuvier, 1803)

1) Large parapodial lobes (fig. 13 flic.kr/p/2kZqF9d ).

2) Not speckled with glistening blue or turquoise.

3) Oral veil enrolled to resemble large oral tentacles (fig.14 flic.kr/p/2kZqF93 ).

4) Usual maximum length 120 mm.

 

Habits and ecology

E. viridis lives on the lower shore and in the shallow sublittoral where there is enough light for its food algae. The single row of radular teeth, adapted to only slitting and cutting (Taylor, 1968), restricts E. viridis to suctorially feeding from algae with few or no internal cell walls subdividing the cytoplasm. The leading tooth is used to puncture algal cell walls whereas the newer, unused teeth function as a spear shaft, and the older worn out teeth are retained in a coil (C.D. Trowbridge 2021, pers. comm., 16 May). Suitable algae in north-west Europe include the siphonaceous green Codium (fig.15 flic.kr/p/2kZtuS6 ) and Bryopsis (fig. 16 flic.kr/p/2kZqF67 ) and the coenocytic green Cladophora (fig. 17 flic.kr/p/2kZqF5f ) and Chaetomorpha and red Griffithsia, Halurus, Dasya, and Dasysiphonia (Trowbridge, 2010; van Bragt, 2004 and C.D. Trowbridge 2021, pers. comm., 9 May). Other coenocytic and siphonaceous species may be consumed when locally available. These vary geographically and with the dates of local invasion by suitable alien algal species.

Early publications (Forbes & Hanley, 1853 and Jeffreys, 1869) mentioned E. viridis on the obviously unsuitable vascular plant Zostera which probably had suitable algae growing among or on it. Accurate identification of which precise species and subspecies of algae are consumed often requires close microscopic examination.

In Britain, the most frequently recorded food alga is ‘Codium’ which includes (Brodie et al., 2007) the native species C. tomentosum and C. vermilara, the invasive (since 1953 in Scotland) alien C. fragile subsp. fragile, previously referred to as C. fragile subsp. tomentosoides and the less common, native or long established (since 1826 in Scotland) alien, C. fragile subsp. atlanticum. These species and subspecies are difficult for recorders to differentiate and there are many misidentified records, but E. viridis can distinguish them as they find the thinner utricle walls of the common alien C. fragile subsp. fragile easier to penetrate than in the others. The slugs have a marked preference for it whenever it is available, and their associated growth rates and maximum body size are greater than when other algal species are consumed (Trowbridge & Todd, 2001). In contrast, of 886 thalli examined of C. fragile subsp. atlanticum from eleven sites all around Scotland, not one had E. viridis on it (Trowbridge & Todd, 2001).

Historically, E. viridis may have frequently fed on Cladophora (figs. 1 flic.kr/p/2kZtvp3 & 17 flic.kr/p/2kZqF5f ) but it is now only rarely used at sites where the preferred alien C. fragile subsp. fragile is still absent (pers. obs. and Trowbridge & Todd, 2001). Experiments showed that those born from adults feeding on the alien lacked the ability to feed or grow on Cladophora. There may have been a historic host shift from Cladophora to Codium fragile subsp. fragile (Trowbridge & Todd, 2001).

Body colour appears to vary with the algal species ingested; dull olive-green with Codium (fig. 6 flic.kr/p/2kZkX1n ), greenish with other green algae and reddish-brown with most red algae (fig. 1 flic.kr/p/2kZtvp3 ). Van Bragt (2004) correlated in the Oosterschelde, Netherlands, cream (fig. 5 flic.kr/p/2kZtvf5 ) with Dictyota dichotoma and pink, red or orange (fig. 5 flic.kr/p/2kZtvf5 ) with the alien Dasysiphonia.

Chloroplasts are sequestered from the ingested cytoplasm of Codium spp. and continue photosynthesis for less than 24 hours within the slug’s body. They may be of a small but significant benefit to the animal as symbiotic organelles if constantly renewed by feeding (Taylor, 1968). It is not known if this phenomenon applies to other algal host species (Trowbridge & Todd, 2001).

There is no record of the large, mobile parapodial lobes being used by E. viridis in active swimming, but they assist when it drifts on currents, and their large surface may assist respiration or short term photosynthesis of ingested chloroplasts in the dendritic digestive gland visible in the surface.

Spawn is deposited on food algae (fig. 6 flic.kr/p/2kZkX1n ) in north-west Europe from May to October, when the mean monthly water temperature is above 10° C (Rasmussen, 1973). When on a flat surface, it forms a spiral cord of about one and a half turns, diameter about 5.5 mm (fig. 18 flic.kr/p/2kZqF2e ), containing over 800 ova (Rasmussen, 1973). Spawn colour is reported to vary with the algal species eaten by the adult; reddish-yellow for Chaetomorphum linum in Denmark (Rasmussen, 1973), lemon-yellow to bluish white for Cladophora and white for Codium (Trowbridge & Todd, 2001), but variation in hue with age is also likely. After 5 to 12 days, planktonic larvae emerge for a long larval stage of 30 to 46 days at 15° C (Trowbridge & Todd, 2001) before settling and metamorphosing on a food alga. Lifespan is 12 to 15 months. The length when fully grown varies geographically from a norm of about 27 mm in the Mediterranean to 45 mm in north-west Europe with an extreme specimen of 70 mm in the Netherlands (Trowbridge & Todd, 2001). Within a given area, length is probably affected by diet, being less on the native Cladophora than the aliens Codium fragile subsp. fragile and Dasysiphonia (to 70 mm), but uncontrolled variables at diverse sites render quantitative comparisons uncertain.

 

Distribution and status

E. viridis occurs from Shetland and Norway into the Mediterranean and into the Baltic as far as Kiel, GBIF map www.gbif.org/species/5192088 . It is widespread around Britain and Ireland, and locally common except in the North Sea which has few records on the NBN UK map species.nbnatlas.org/species/NBNSYS0000175103 . Jeffreys (1869) commented on the absence of records from the North Sea, and extensive fieldwork and search of historic records produced no record of it on the Scottish coast of the North Sea in McKay & Smith (1979). Almost all North Sea records of E. viridis on NBN Atlas, including some for Scotland, are post 2000 except for two in North Yorkshire (C. Todd, 1975 and K. Hiscock, 1993). It appears that since 2000 its population has increased in the North Sea from absence in Scotland and very low numbers in England to a noticeable presence (fig. 19 flic.kr/p/2kZSRgX ). If not because of increased recording and reporting online by divers, this increase may be due to recent warming of the North Sea (Hughes et al., 2010) which is colder in winter than other seas around Britain. This would accord with the situation in the Netherlands. It was first recorded there in 1899 but was absent 1938 – 1989, recovered until locally wiped out in the severe winters of 1995/96 and 1996/97 and reappeared in 1998 in the Oosterschelde to become one of the commonest sea slug species in that estuary by 2004 (van Bragt, 2004).

 

Acknowledgements

I am most grateful to Cynthia D. Trowbridge for her help and advice with the text, but any errors or omissions are my (IFS) responsibility.

I thank Rokus Groeneveld www.diverosa.com/nederland.htm , Penny Martin, Chris Rickard, Malcolm Storey www.bioimages.org.uk/ and Stefan Verheyen for use of their images and Peter H. van Bragt for help with literature.

 

References and links

AlgaeBase Codium fragile (Suringar) Hariot 1889 accessed 10 May 2021 www.algaebase.org/search/species/detail/?species_id=3638

 

Brodie, J. A., Maggs, C. and John, D. M. (eds.). 2007. Green Seaweeds of Britain and Ireland. British Phycological Society.

 

Forbes, E. & Hanley S. 1853. A history of the British mollusca and their shells. vol. 3, London, van Voorst. archive.org/details/historyofbritish03forbe/page/614/mode...

 

Garstang, W. 1890. A complete list of the Opisthobranchiate Mollusca found at Plymouth. J. mar. biol. Ass. U.K., 1:399–457.

plymsea.ac.uk/id/eprint/50

 

Hughes, S.L., Holliday, N.P., Kennedy, J., Berry, D.I., Kent, E.C., Sherwin, T., Dye, S., Inall, M., Shammon, T. and Smyth, T. 2010. Temperature (Air and Sea) in MCCIP Annual Report Card 2010-11, MCCIP Science Review, 16pp. www.mccip.org.uk/arc

 

Jeffreys, J.G. 1869. British conchology. vol. 5 . London, van Voorst.

archive.org/details/britishconcholog05jeffr/page/31/mode/1up

 

Taylor, D.L. 1968. Chloroplasts as symbiotic organelles in the digestive gland of Elysia viridis (Gastropoda, Opisthobranchia). J. mar. biol. Ass. U.K., 48 (1): 1 - 15. Abstract: www.cambridge.org/core/journals/journal-of-the-marine-bio...

 

Thompson, T.E. 1976. Biology of opisthobranch molluscs 1. London, Ray Society.

 

Trowbridge, C. D., Hirano, Y. J. and Hirano, Y. M. 2010. Sacoglossan opisthobranchs on northwestern Pacific shores: Stiliger berghi Baba, 1937, and Elysia sp. on filamentous red algae. Veliger 51: 43-62. www.researchgate.net/publication/235703273_Sacoglossan_Op...

  

Trowbridge, C. D, and Todd, C. 2001. Host-plant change in marine specialist herbivores: ascoglossan sea slugs on introduced macroalgae. Ecological Monographs, 71 (2): 219–243. Ecological Society of America.

www.researchgate.net/publication/250075515_Host-Plant_Cha...

 

Van Bragt, P. H. 2004. The sea slugs, Sacoglossa and Nudibranchia (Gastropoda, Opisthobranchia), of the Netherlands. Vita Malacologica, 2: 3 - 32 and Pl. 1 -10.

 

Current taxonomy; World Register of Marine Species www.marinespecies.org/aphia.php?p=taxdetails&id=139686

 

GLOSSARY

chloroplast = organelle in the cytoplasm of a plant or algal cell which contains chlorophyll that photosynthesises to capture and store the energy from sunlight.

 

coenocytic = (of algae) with parts made up of multinucleate, large masses of cytoplasm enclosed by the wall of each large cell.

dendritic = branching like boughs, branches and twigs of a tree.

 

parapodial lobes = flaps of the parapodium, lateral outgrowths of foot, which extend up the sides of some sea slugs.

 

propodial = at the front of the foot.

radula = chitinous ribbon of teeth

rhinophore = chemo-receptor tentacle; nudibranch and most sacoglossan sea slugs have a pair on top of the head.

 

siphonaceous = (of algae) entire thallus (‘plant’) is coenocytic with no internal cell walls subdividing the cytoplasm.

utricle = swollen cortical sac-like portion of filaments in Codium and many related green algae.

 

vascular plants = plants which, unlike algae, have vascular tissues to transport water and nutrients through the plant, true absorptive roots and leaves specialized in photosynthesis. Usually terrestrial or in freshwater; a few, such as Zostera, live in the sea.

 

veliger = shelled larva of marine gastropod or bivalve mollusc which moves by action cilia on a velum (bilobed flap).

 

Typical sizes in Britain (adults usually 8-12 mm high). Convolute shell, i.e. all earlier whorls concealed by enveloping final whorl.

1: smallest specimen palest as pigmented layer deposited by external mantle is thinner than on larger older specimens.

2: shell broadest towards apical end (posterior of animal).

3: slight mound indicates position of hidden apex.

Heights (longest shell-dimensions) 8.7 mm, 9.6 mm, 11.2 mm. west Scotland. April 1976.

 

Full SPECIES DESCRIPTION BELOW

Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/

 

Trivia arctica (Pulteney, 1799)

Revised December 2023.

 

Synonyms: Cypraea arctica Pulteney, 1779 ; Cypraea europaea Montagu, 1808 [= aggregate of T. monacha and T. arctica in Forbes & Hanley, Jeffreys, and many authors pre-1925]; Cypraea europaea var. minor Marshall, 1893; Trivia mollerati Locard, 1894.

Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=141744

Meaning of name: (Latin) Trivia = a common thing; arctica = northern.

Vernacular: Northern cowrie, Unspotted cowrie (English); Cragen fair y gogledd (Welsh); Ongevlekt koffieboontje (Dutch); Nordlig kauri (Danish). Sometimes “Arctic cowrie” is used, but a misnomer as not a typical Arctic species, just a few records beyond Arctic Circle in Norway where Atlantic Drift brings anomalous temperate water far north.

Names applied to both T. monacha and T. arctica: European cowrie, nun, sea-cradle, maiden, stick-farthing, (English); Groatie-buckie (Scots); Cragen fair (Welsh); Europäische Kauri (German); Pucelage; Pou-de-mer; Porcelaine puce; Grain de café (French); Kaffebønne (Norwegian); Freirinha (Portuguese); Porcelanita (Spanish).

 

GLOSSARY below.

 

Adult shell description

In Britain, adult T. arctica are usually from 8 mm to 12 mm high (longest dimension of shell) 01Ta flic.kr/p/Cfnfpb. They are broadest towards the apical end. In the Mediterranean they are usually smaller; Vayssière (1923) in Lebour (1933) gives height extremes of 6-12 mm at Marseilles. The shell is ovoid with a flatter apertural/ventral face 02Ta flic.kr/p/D5AdRz , likened in its vernacular names to a coffee bean (Dutch, French, Norwegian) or kernel of oats (Scots). The shell is convolute with all earlier whorls hidden from view by the enveloping final whorl; a slight pimple or mound on posterior end sometimes indicates the position of the hidden apex 01Ta flic.kr/p/Cfnfpb. It is solidly built with an adult sculpture of 20-25 ribs crossing the entire shell with a few short intervening ribs. The intervening grooves are the same width as the ribs. The ribs of left and right sides are perfectly aligned where they meet with no discontinuity on the dorsum (van Nieulande et al., 2022 & 27.1Ta flic.kr/p/2pkGM2T . There is a thickened white labial varix on the left 02Ta flic.kr/p/D5AdRz .

The aperture is a gently bowed slit positioned ventrally on the living animal, and it extends the entire height of the shell. The outer (palatal) lip of the aperture is curved out of sight into the interior of shell 03Ta flic.kr/p/CKKP6m . The columellar region is a concave furrow and its ribs protrude as teeth. An expansion of the aperture slit at the anterior forms an inhalant siphonal canal, and narrower expansion at the posterior forms an exhalant canal. The adult shell is opaque white internally and externally, apart from a thin external pinkish layer deposited by the external mantle in grooves dorsally and laterally; the ribs receive less pigment so are paler than the grooves 03Ta flic.kr/p/CKKP6m . The ventral surface and labial varix are white 02Ta flic.kr/p/D5AdRz . Shells of live animals are glossy and lack erosion or epizooic growths as they are protected and maintained by the expanded mantle depositing shell material on the exterior 04Ta flic.kr/p/D3j1Ws . There is no operculum or periostracum on adults.

Post-veliger shell development

The veliger larva metamorphoses when its shell is about 1.25 mm diameter (Lebour, 1933). The early juvenile shell is flimsy, smooth, white and has a typical gastropod aperture and spire. At this stage it is not possible to differentiate the shell from that of T. monacha 04.1Ta flic.kr/p/2pjL6Za unless the diagnostic foot is visible 04.2Ta flic.kr/p/2pjLJAh . As it grows, the spire is completely enveloped by the final whorl. Post-veliger juvenile shells grow in the normal three-layered helical fashion of most other snails (Meyer & Paulay, 2005). This changes after about six months when: i) the spire is completely enveloped by the body whorl, ii) the shell is thickened mainly internally, but also externally, with layers of differing crystalline structure, iii) the ribs act as teeth along both sides of the narrowed aperture, iv) the ribs and grooves complete their formation ventrally and dorsally on the body-whorl. The shell now has adult form, but is pure white as the outer pinkish layer has not yet been deposited 04.3Ta flic.kr/p/2pkpebK .

Adult shell development is completed by deposition externally of a thin, outermost pinkish layer mainly in the grooves, and ventrally the shell remains white.

 

Body description

The cephalic tentacles are long, slender and translucent white 10Ta flic.kr/p/CKKHdQ to mustard-yellow 11Ta flic.kr/p/CDnCcB , usually with opaque, hyphen-like streaks of yellow. The large inhalant siphon is a rolled extension of the mantle 09Ta flic.kr/p/DcSQig coloured whitish 12Ta flic.kr/p/D3iU6U to pale yellow 13Ta flic.kr/p/CfuduK ; often with stronger yellow at the tip and sometimes opaque white or yellow marks. The siphon protrudes, often held high, from a short, wide expansion of the aperture slit at the anterior which acts as a siphonal canal 09Ta flic.kr/p/DcSQig & 13Ta flic.kr/p/CfuduK . The exhalant siphon is formed by a fold of mantle resting within an expansion of the aperture slit forming the posterior siphonal canal 07Ta flic.kr/p/Cfn8gU . The much thickened and lobulated mantle can expand over the entire exterior 12Ta flic.kr/p/D3iU6U . In Britain, when stretched to full extension, the mantle is often translucent enough for the shell to be discerned under it. Its general colour is whitish, brownish or orange-brown. It is palest ventrally and usually greyed by a spray of very fine grey particles which may locally aggregate into small blotches 12Ta flic.kr/p/D3iU6U , and occasionally form lines aligned with grooves of shell. The mantle rim is usually pale yellow 12Ta flic.kr/p/D3iU6U or whitish and is often unobtrusive 04Ta flic.kr/p/D3j1Ws . There are usually several pitch-brown/black pigment blotches near, or interrupting, the yellow/white rim 10Ta flic.kr/p/CKKHdQ . On the fully expanded mantle the blotches are often mistaken for the similar dorsal blotches on the shell of T. monacha 12Ta flic.kr/p/D3iU6U .

Colour saturation varies between individuals, and on any individual increases with degree of mantle contraction 14Ta flic.kr/p/DcSran . Specimens from southern Europe usually have more saturated colours and sometimes have a dark brown mantle. Light yellow or whitish papillae often protrude from the mantle. They vary in size, shape and number and are occasionally “hedgehog-like” 15Ta flic.kr/p/Cfuc4Z ; sometimes absent 11Ta flic.kr/p/CDnCcB and sometimes extremely prominent and branched. They are usually more prominent on juveniles (Lebour, 1933). Post-veliger juveniles have paler body pigmentation and at the earliest stages can be entirely white 04.2Ta flic.kr/p/2pjLJAh . The mantle on later juveniles is translucent, yellowish with minute blackish purple particles which coalesce into blotches near the mantle edge, only when adult 31Ta flic.kr/p/DcJu9q . Juveniles often have yellow tipped papillae on the mantle and minute dark spots on the body and base of siphon, and sometimes pale yellow flecks on siphon and tentacles (Lebour, 1933).

The foot at all stages can extend beyond the shell by more than 50% of shell-length 16Ta flic.kr/p/CDnwTF . It is translucent, whitish with varying amounts and intensity of yellow 13Ta flic.kr/p/CfuduK or orange-red 17Ta flic.kr/p/CKKznQ tinting. The dorsal surface of the foot has a distinct, broad, peripheral chamfer 13Ta flic.kr/p/CfuduK , often with some irregular, opaque, yellow 10Ta flic.kr/p/CKKHdQ or whitish 12Ta flic.kr/p/D3iU6U blotches but not extensive well-defined lines. The chamfer narrows at the posterior tip, often giving it a flat 18Ta flic.kr/p/D5zWZK or concave 15Ta flic.kr/p/Cfuc4Z outline which is frequently marked with about 6 short yellow streaks. The anterior of the foot is bilaminate 19Ta flic.kr/p/CKKxxs .

The sole is coloured as the dorsum of the foot or paler 19Ta flic.kr/p/CKKxxs , but without opaque marks, though those on the dorsal surface may show through it 20Ta flic.kr/p/D5zUR6 . It has a median groove containing a posterior pedal mucus gland 07Ta flic.kr/p/Cfn8gU . In the anterior half of the sole on females there is a ventral pedal gland the opening of which often has a more saturated colour 21Ta flic.kr/p/D3iJt7 . A transverse fold allows the anterior of the foot to fold back on itself to bring the ventral gland forwards 22Ta flic.kr/p/Cfu4CX . Unlike most gastropods which have a single columellar muscle/pedal retractor muscle, T. arctica has two because of its expanded body whorl.

A large flat leaf-like penis arises behind and below the right tentacle on males (Lebour, 1933).

Key identification features

Trivia arctica

1) Adult pink shell has no pitch-brown/black dorsal marks 10Ta flic.kr/p/CKKHdQ but dark dorsal blotches on rim of fully extended mantle of adult T. arctica are often confused with similar marks on shell of T. monacha.

2) The dorsal surface of the foot of T. arctica at all stages is whitish to yellowish or reddish orange, often with some irregular opaque marks, but is not covered by a network of opaque yellow or white lines 12Ta flic.kr/p/D3iU6U . * Most reliable diagnostic feature.

3) Post veliger juveniles with smooth white shells 04.1Ta flic.kr/p/2pjL6Za cannot be differentiated from juvenile T. monacha, unless the dorsal surface of the foot is seen not to be covered by a network of white or yellow lines 04.2Ta flic.kr/p/2pjLJAh .

4) Final stage juveniles of both T. arctica and T. monacha have adult-like ribs but are white and lack pigment blotches 04.3Ta flic.kr/p/2pkpebK . T. arctica can be identified by the dorsal surface of the foot lacking a network of lines, or by the perfect dorsal alignment dorsally of the shell ribs from left and right sides 23Ta flic.kr/p/2nuWGWu . The same applies to bleached dead adult shells.

5) Extended mantle of T. arctica has pitch-brown/black dorsal marks (vary in size and number, but often three) where edges meet 12Ta flic.kr/p/D3iU6U . Juvenile has grey/black particles that do not coalesce to form dark discs elsewhere on mantle. (Lebour, 1933).

6) Large flat leaf-like penis on males of T. arctica. (Lebour, 1933).

7) Veliger larvae of T. arctica have yellowish intestines, and very little dark pigment on sides of stomach; always has less pigment than T. monacha larvae. Late stage veligers have velum of four long, thin lobes 24Ta flic.kr/p/CDnozB (Lebour, 1933).

8) 3.5mm post-veliger juveniles of T. arctica have yellowish (not orange or bright yellow) soft-parts with minute dispersed blackish-purple spots on exposed mantle, not congregated into disc-shaped groups (Lebour, 1933).

9) Transparent egg capsules of T. arctica, unknown until 2017, are embedded in compound ascidian with neck projecting from surface 25Ta flic.kr/p/Cfu1R4 & 21.1Ta flic.kr/p/234LSrM , veligers in plankton from January to May in southern England 24Ta flic.kr/p/CDnozB .

 

Similar species

Trivia monacha (da Costa, 1778)

1) Adult shell has three pitch-brown/black dorsal marks 27Ta flic.kr/p/CDnkwn .

2)The dorsal surface of the foot of T. monacha at all stages is orange/yellow covered by a network of opaque yellow or white lines 27Ta flic.kr/p/CDnkwn . * Most reliable diagnostic feature.

3) Juveniles with smooth white shells 04.1Ta flic.kr/p/2pjL6Za cannot be differentiated from T. arctica, unless the dorsal surface of the foot is covered by a network of white or yellow lines 27Ta flic.kr/p/CDnkwn .

4) Final stage juveniles of T. arctica and T. monacha both have ribs, are white and lack dark blotches 27.1Ta flic.kr/p/2pkGM2T . T. monacha can be distinguished by network of lines on foot, or by the dorsal misalignment of some shell ribs from left and right sides 23Ta flic.kr/p/2nuWGWu . The same applies to bleached dead adult shells. Rare exceptional T. monacha lack misalignment.

5) Extended mantle of T. monacha is varied but usually has an unbroken orange border at the edge not accompanied three large pitch-brown/black blotches on the mantle 27Ta flic.kr/p/CDnkwn .

6) Filiform, cylindrical penis on males (Lebour, 1933).

7) Veliger larvae have almost black intestines & stomach, and dark digestive gland. Late stage veligers have slight lateral bay in the vela, but insufficient to change them into four long thin lobes 24Ta flic.kr/p/CDnozB (Lebour, 1933).

8) 3.5mm (and larger) post-veliger juveniles have orange or bright yellow soft parts 28Ta flic.kr/p/Day2bu , and grey/black particles that coalesce to form spots grouped into dark discs scattered over mantle 29Ta flic.kr/p/CftVz2 (Lebour, 1931 & 1933).

9) Egg capsules with orange eggs embedded in compound ascidian with neck projecting from surface, ( veligers April to September in S. England) 25Ta flic.kr/p/Cfu1R4 .

 

Marsenia perspicua (Linnaeus, 1758) 30Ta flic.kr/p/CDnfUX

Inhalant siphon and sometimes roughened surface resemble Trivia.

Mantle halves fused so never retract to expose shell.

Fragile, white, internal, ear-shape shell.

Transparent egg-capsules with white eggs embedded in compound ascidian with lid flush with surface apart from rim 25Ta flic.kr/p/Cfu1R4 & 26Ta flic.kr/p/Cfu178 .

 

Simnia patula (Pennant, 1777) 31.1Ta flic.kr/p/2pmaPvE

Juvenile shells of T. arctica might be mistaken for S. patula.

Shell drawn out into anterior and posterior siphonal canals.

Two sides of exterior mantle meet on right side of shell, not along median line.

Mantle white or orange with orange or red transverse lines.

S. patula lives 15-75 m deep and not intertidally.

 

Erato voluta (Montagu, 1803) 32Ta flic.kr/p/2nbgWAZ

Strong shell retains exposed spire throughout life.

Animal narrower at anterior, reflecting the shape of the concealed shell.

Stout inhalant siphon and foot are pink or whitish with red spots.

White spots on tentacles.

When fully extended, two sides of dark papillate mantle meet at dorsal median line.

 

Exotic cowries

Attractive tropical cowries and smaller, duller ones used in school bean-bags and historically used as currency are dropped by humans on beaches, and washed up in the Netherlands from historical shipwrecks.

 

Habits and ecology

T. arctica is usually found near its compound and unitary ascidian prey on hard substrate at LWS and more frequently sublittorally to 100 m in Norway and 1000 m in southern Europe (Fretter & Graham, 1981). It feeds on Diplosoma listerianum especially var. gelatinosum, the preferred food near Plymouth (Lebour, 1933); on Polyclinum aurantium, the preferred food in Brittany (Pelseneer, 1926), Botryllus schlosseri, especially its yellow and orange forms, Trididemnum, Botrylloides leachi and the unitary Ciona intestinalis and Corella parallelogramma 08.2Ta flic.kr/p/2cQ7E8T & 22.1Ta flic.kr/p/2bpJEk6 .

It examines the surface of the ascidian with its inhalant siphon and, from a pouch in its head, extends a proboscis containing radula and jaws to cut through the test to expose the zooid. Both test and zooid are ingested, and fragments of indigestible test are voided in the faecal rods or pellets. Unitary ascidians, such as Corella parallelogramma 22.1Ta flic.kr/p/2bpJEk6 and Ciona intestinalis (D. Kipling, 2018. pers. comm. 11 Nov.) are sometimes eaten by forcing the proboscis into them through the oral siphon, avoiding the need to bite through the indigestible test.

The body is very pliable and can withdraw into/extend from the narrow aperture with speed and ease. The siphon is usually extended first to test the water 14Ta flic.kr/p/DcSran .

The anterior pedal gland in the bilaminate anterior edge of the foot 19Ta flic.kr/p/CKKxxs , and posterior pedal gland in the median groove of the sole, produce mucus to assist movement, and many other glands in the sole and mantle exude a variety of secretions, not all mucal, and some probably repugnatory. The female has a yellow opening to a ventral pedal gland in the anterior half of her foot. The foot can fold up at a right-angle on a traverse line in front of the gland to position the gland on a leading edge for its protrusion and operation in egg capsule formation 05Ta flic.kr/p/D3j1pq & 22Ta flic.kr/p/Cfu4CX.

Respiratory water is taken in through a long inhalant siphon projecting from the anterior siphonal canal of the shell and passes into the mantle cavity where an osphradium tests the water-quality before passing it through the ctenidium. Water leaves the shell via an exhalant siphon in the posterior siphonal canal.

T. arctica breeds, at Plymouth, from late autumn to spring. The female is fertilized internally by the large flat leaf-like penis of the male. Until 2017, egg laying had not been recorded but was assumed to be similar to that of T. monacha (Fretter & Graham, 1981; and Wigham & Graham, 2017). In March 2017, a Belgian diver, Stefan Verheyen, photographed laying egg capsules by T. arctica 21Ta flic.kr/p/D3iJt7 & 21.1Ta flic.kr/p/234LSrM , and the details were, as anticipated, similar to those of T. monacha. The egg-capsule is transparent showing the crowded orange ova within. It is inserted in a hole bitten into the compound ascidian Diplosoma listerianum, a food favoured by it and T. monacha, and possibly other compound ascidians. The female protrudes the ventral pedal gland embedded in her sole to drive the capsule into the hole and give it its final shape with the two lobes of its bifid tip 25Ta flic.kr/p/Cfu1R4 . The capsule is a spheroidal flask with a funnel-shape neck which protrudes well above the surface of the ascidian, but the neck is easily overlooked as its colourless transparent nature makes it almost invisible 25Ta flic.kr/p/Cfu1R4 .

The eggs hatch into planktonic echinospira larvae with a velum with four long lobes. Larvae were taken in plankton nets by Lebour in coastal waters from January to May, while T. monacha larvae were taken from April to September (Fretter & Graham, 1962) 24Ta flic.kr/p/CDnozB . An echinospira larva has a 'double shell'; the exterior one is flimsy, transparent, colourless and shiny. Fretter & Graham (1962) interpreted the exterior one as the periostracum layer separated from the inner calcareous shell. The intervening gap is filled with seawater and helps reduce the specific gravity of the larva to near neutral buoyancy, and the increased surface area slows the rate of sinking, so easing the effort needed to orientate and maintain position in the water column (McCloskey, 1972). The inner calcareous shell contains the larval animal. Though T. arctica has smaller adults than T. monacha, its larvae are larger at equivalent stages and its vela are more developed probably because it lives in deeper off-shore waters and needs more power to maintain position in the water column.

At metamorphosis, the larval operculum and outer shell/periostracum are shed and the mantle spreads over the exterior of the inner shell. “The number of old [adult] shells taken surprisingly exceeds that of the young.” (Forbes & Hanley, 1853). This quote might be explained by poor survival of thin, fragile, dead juvenile shells on strandlines, but live juveniles are much rarer than live adults on suitable shores, although, when present, several may be found at the same location. Divers seem to see juveniles more often 31Ta flic.kr/p/DcJu9q . Juveniles assume adult form with ribbed pink shells about 6 months after metamorphosis.

Distribution and status

T. arctica occurs from northern Norway to Gibraltar and the western Mediterranean, but is absent from the Baltic and Danish and German coasts apart from dead shells in the vicinity of Helgoland, GBIF map www.gbif.org/species/5192808 . It lives on hard substrate around most coasts of Britain and Ireland but is absent or scarce in the north-east Irish Sea, from Flamborough Head to Kent and much of the east coast of Scotland. U.K. map NBN species.nbnatlas.org/species/NBNSYS0000178458 .

 

Acknowledgements

For help with specimens, images, information and/or literature, I gratefully thank Maëlan Adam, Jim Anderson, Nils Aukan, Karen Boswarva, Pierre Corbrion, Dick Hoeksema, David Kipling, Jan Light, Paula Lightfoot, Chris Rickard, Stefan Verheyen and Dawn Watson.

 

Links and references

Browne, E.T. 1898. On keeping medusae alive in an aquarium. J. Mar. Biol. Ass. 5 (2): 176-180. [Description of “plunger jar” used by Lebour to rear Trivia] plymsea.ac.uk/192/

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853), London, van Voorst. (As Cypræa europæa [agg.]); pp. 495-497. archive.org/stream/ahistorybritish05forbgoog#page/n508/mo...

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

Fretter, V. and Graham, A. 1981. The prosobranch molluscs of Britain and Denmark. Part 6 – Cerithiacea, Strombacea, Hipponicacea, Calyptraeacea, Lamellariacea, Cypraeacea, Naticacea, Tonnacea, Heteropoda. J. Moll. Stud. Suppl. 9: 285-363.

 

Graham, A. 1988. Molluscs: prosobranch and pyramidellid gastropods. Synopses of the British Fauna (New Series) no.2 (Second edition). Leiden, E.J.Brill/Dr. W. Backhuys. 662 pp.

 

Høisæter, T. 2009. Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna norvegica 28: 5-106. www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/563

 

Jeffreys, J.G. 1862-69. British conchology. vol. 4 (186). London, van Voorst. (As Cypræa europæa agg.) archive.org/stream/britishconcholog04jeff#page/402/mode/2up .

 

Lebour, M.V. 1931. The larval stages of Trivia europea. J. Mar. Biol. Ass. 17 (3): 819-832. [Aggregate species, but nearly all details are of T. monacha.] plymsea.ac.uk/698/

 

Lebour, M.V. 1933. The British species of Trivia: T. arctica and T. monacha. J. Mar. Biol. Ass. 18 (2): 477-484. plymsea.ac.uk/782/

 

Lebour, M.V. 1935. The echinospira larvae of Plymouth. Proc. zool. Soc. Lond. 163-174.

 

Lebour, M.V. 1937. The eggs and larvae of the British prosobranchs with special reference to those living in the plankton. J. mar. biol. Ass., 22: 105 – 166. plymsea.ac.uk/953/

 

McCloskey, L.R. 1972. Development and ecological aspects of the echinospira shell of Lamellaria rhombica Dall (Prosobranchia; Mesogastropoda). Ophelia 10 (2): 155-168. Preview www.tandfonline.com/doi/abs/10.1080/00785326.1972.10430111

 

McKay, D. & Smith, S.M. 1979. Marine mollusca of East Scotland. Royal Scottish Museum, Edinburgh.

 

Meyer, C. & Paulay, G. 2005. Shell microstructure. Cowrie Genetic Database Project, Florida Museum of Natural History. www.flmnh.ufl.edu/cowries/microstructure.html

 

Pelseneer, P. 1926. Note d'embryologie malacologique. Ponte et développement de Cypræa europea, etc. Bull. Biol. de la France et de la Belgique 60 (1): 88-112. [Cited in Lebour, 1933, as having mistakenly interchanged descriptions of penes of T. monacha and T. arctica]

 

Pelseneer, P. 1932. La métamorphose préadulte des Cypræidæ. Bull. Biol. de la France et de la Belgique 66 (2): 149-163. [Cited in Lebour, 1933, as having corrected mistaken interchange made in 1926 of descriptions of penes of T. monacha and T. arctica]

 

Van Nieulande, F.A.D., Hoeksema, D.F., Nijhuis, H.W. & Rijken, A.C. 2022. De fossiele schelpen van de Nederlandse kust II, deel 17. Velutinidae, Triviidae, Eratoidae en Ovulidae Spirula 431: 16 – 25. www.researchgate.net/publication/360897905_De_fossiele_sc...

 

Vayssièrre, A. 1923. Recherches Zoologiques et anatomiques sur les mollusques de la Famille des Cypræidés. Annls Mus. Hist. nat. Marseille Zoologie. 18: 1-120. (In Lebour, 1933.)

 

Verheyen, S. & Smith, I.F. 2018. Discovery of the egg capsule of Trivia arctica (Pulteney, 1799) Mollusc World 46: 8-9 Conchological Society of Great Britain and Ireland. conchsoc.org/MolluscWorld46

 

Wiese, V. and Janke, K. 2021. Die Meeresschnecken und –muscheln Deutschlands Wiebelsheim, Quelle & Meyer.

 

Wigham, G.D. & Graham, A. 2017. Marine gastropods 2: Littorinimorpha and other, unassigned, Caenogastropoda. Synopses of the British Fauna (New Series) no.61. (344 pages). Field Studies Council, Telford, England.

  

Glossary

aperture = mouth of gastropod shell; outlet for head and foot.

cephalic = (adj.) of or on the head.

columella = solid or hollow axial “little column” around which gastropod shell spirals

 

columellar = (adj.) of or near central axis of spiral gastropod.

convolute = (adj.) body whorl of shell envelopes and conceals the spire.

ctenidium = comb-like molluscan gill; usually an axis with a row of filaments or lamellae on one or two sides.

 

dorsoventrally flattened = pressed flat from above and below like a pancake.

echinospira = special form of drifting larva with an inner and outer shell, and the intervening space filled with sea water.

 

epizooic = (adj.) of non-parasitic organisms living on surface of animals.

ELWS = extreme low water spring tide (usually near March and September equinoxes).

filiform = threadlike.

height = (of gastropod shells) distance from apex of spire to base of aperture but, as apex concealed, the longest dimension on Trivia.

 

labial varix = especially strong or broad costa (rib) along or near outer lip of aperture.

mantle = sheet of tissue which secretes the shell and forms a cavity for the gill in most marine molluscs. Confined to the shell-interior of most British shelled-gastropods, but can also cover exterior on Trivia.

 

operculum = plate of horny conchiolin used to close shell aperture; absent from Trivia .

osphradium = organ for testing water quality usually near ctenidium (gill).

papilla = (pl. papillae) small cone-shaped protrusion of flesh.

papillate = covered in papillae

periostracum = thin horny layer of chitinous material often coating shells.

plankton = animals and plants that drift in pelagic zone (main body of water).

suture = groove or line where whorls of gastropod shell adjoin.

test = (of ascidian) a.k.a. tunic; outer cellulose sheath containing zooid.

umbilicus = cavity up axis of some gastropods.

veliger = shelled larva of marine gastropod or bivalve mollusc which swims by beating cilia of a velum (bilobed flap).

  

Solar Plexus: The Secret Gravitational System

ISBN: 1456300474

 

Whiffs of Bliss

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RESOURCES / BIBLIOGRAPHY:

 

1 Abraham | Esther & Jerry Hicks

Law of Attraction in Action [series]

The Vortex

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2Paris Hilton

Confessions of an Heiress: A Tongue-in-Chic Peek Behind the Pose (p.10)

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3 Michael J. Losier

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4 Gravity | Gravitation | Gravitational Waves + Radiation

 

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•Gravitation

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•Gravitational Waves

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science.nasa.gov/science-news/science-at-nasa/2008/19mar_...

 

•Gravitational Radiation

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5 Vibration | Schumann Resonance

 

•Vibes: www.google.com/dictionary?aq=f&langpair=en|en&q=vibration&hl=en

 

•Schumann Resonance: www.earthbreathing.co.uk/sr.htm

  

6 Sonia Ricotti

The Law of Attraction, Plain and Simple

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7 Anthony Robbins

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8 Alan Cohen

Why Your Life Sucks, and What to Do About It

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9 Florence Scovel Shinn

The Wisdom of Florence Scovel Shinn: The Game of Life and How to Play It

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10 Karla McLaren

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Candace Pert

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11 Story of Stuff

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12 The Quantum Activist [DVD]: quantumactivist.com/

Amit Goswami: www.amitgoswami.org

  

13 Cocos Island | Blue Planet

 

•Cocos Island: Discover Planet Ocean: The World Beneath [DVD]

whc.unesco.org/en/list/820

 

•Blue Planet: dsc.discovery.com/tv/blue-planet/blue-planet.html

www.blueplanetbiomes.org

www.imdb.com/title/tt0296310

  

14 Ramtha

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God Only Knows What You Know [CD]

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15 Fred Alan Wolf

Mind into Matter: A New Alchemy of Science and Spirit

Dr. Quantum’s Little Book Of Big Ideas: Where Science Meets Spirit

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16 What the Bleep Do We Know?! [DVD] | Down the Rabbit Hole [DVD]

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•John Hagelin

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•Stuart Hameroff

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•Jeffrey Satinover

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17 The Truman Show [DVD]

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•Star Wars

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18 Canticle to the Cosmos [DVD]

Brian Swimme

www.brianswimme.org

  

19 Dr. Joseph Murphy

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20 Space Tourism

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www.spacetourismsociety.org/Space_Tourism_Society/Welcome...

  

21 Entanglement

plato.stanford.edu/entries/qt-entangle/

www.youtube.com/watch?v=Jh8uZUzuRhk

www.youtube.com/watch?v=9lOWZ0Wv218

  

22 David Hawkins

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robertdecker.com/hawkins/welcome.htm

www.beyondtheordinary.net/drhawkins.shtml

  

23 TAO

 

•Fritjof Capra

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www.fritjofcapra.net

 

•Benjamin Hoff

The Tao of Pooh

  

24 Caroline M. Sutherland

The Body Knows

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25 Deepak Chopra

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26 Eckhart Tolle

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27 Deanna Davis

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28 Louise Hay

Heal Your Body

 

You Can Heal Your Life [DVD]

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www.youcanhealyourlifemovie.com

 

Gregg Braden

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29 Kristen & David Morelli

www.everythingisenergy.com

  

30 Max Planck [Planck Scale]

www.pbs.org/wgbh/aso/databank/entries/bpplan.html

www.mpg.de/english/

  

31 The History Channel

The Universe: “Gravity” [Season 2]

www.history.com/shows/the-universe/episodes/season-2

www.history.com/shows/the-universe

 

The Universe: “Ask”

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32 Bruce Lipton: Biology of Belief

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33 Magnetite: wordnetweb.princeton.edu/perl/webwn

 

Magnetite in Human Tissues: A Mechanism for the Biological Effects of Weak ELF Magnetic Fields

Joseph L Kirschvink, Atsuko Kobayashi-Kirschvink, Juan C Diaz-Ricci, and Steven J Kirschvink

Division of Geological and Planetary Sciences, The California Institute of Technology,

Pasadena, California (J. L. K., A. K. -K., J. C. D.); Department of Mathematics, San Diego State University,

San Diego, California (S. J. K.)

www.pnas.org/content/89/16/7683.full.pdf

  

34 Electromagnetism

www.google.com/dictionary?langpair=en|en&q=Electromagnetism&hl=en&aq=f

hyperphysics.phy-astr.gsu.edu/hbase/magnetic/elemag.html

www.britannica.com/EBchecked/topic/183324/electromagnetism

www.phy.syr.edu/courses/modules/LIGHTCONE/maxwell.html

  

•Electricity's Attraction [DVD]

store.discoveryeducation.com/product/show/48342

  

35 Sir Isaac Newton

Principia

 

www.newton.ac.uk/newton.html

www.fordham.edu/halsall/mod/newton-princ.html

csep10.phys.utk.edu/astr161/lect/history/newtongrav.html

  

36 Neil deGrasse Tyson

My Favorite Universe [DVD]

The Teaching Company: 12 Lectures

On Being Round

  

37 Hannah Holmes

The Secret Life of Dust

www.hannahholmes.net

  

38 GRAVITATIONAL WAVE OBSERVATORIES

www.aei.mpg.de/english/research/observatories/index.html

 

•Laser Interferometer Space Antenna (LISA): lisa.nasa.gov/

 

•LIGO: www.ligo-la.caltech.edu/

 

•Fermilab: www.fnal.gov/

 

•CERN: www.cern.ch

public.web.cern.ch/public/en/science/higgs-en.html

  

39 Travis S Taylor

The Science Behind The Secret: Decoding the Law of Attraction

  

40 Potential & Kinetic Energy

hyperphysics.phy-astr.gsu.edu/hbase/gpot.html

  

41 Albert Einstein: Theory of Relativity

 

•Relativity: The Special and General Theory, XIX - The Gravitational Field (p. 74)

By Albert Einstein, Robert W. Lawson

 

•Theory of Relativity: Three Hundred Years of Gravitation

Stephen W. Hawking, W. Israel

 

•PBS: www.pbs.org/wgbh/nova/einstein/relativity/

 

•Max Born: Einstein’s Theory of Relativity

www.hawking.org.uk/index.php/about-stephen

  

42 Brian Greene

The fabric of the Cosmos: Space, Time, and the Texture of Reality

www.columbia.edu/cu/physics/fac-bios/Greene/faculty.html

  

43 Ed Fomalont, Astronomer of the National Radio Astronomy Observatory (NRAO)

Sergei Kopeikin, Physicist at the University of Missouri-Columbia

www.nrao.edu/pr/2003/gravity/

www.csa.com/discoveryguides/gravity/overview.php

  

44 Lightspeed relative to Gravity

fascistsoup.com/2010/05/14/the-speed-of-gravity-why-einst...

www.lbl.gov/Science-Articles/Archive/Phys-speed-of-gravit...

www.metaresearch.org/cosmology/speed_of_gravity.asp

www.desy.de/user/projects/Physics/Relativity/GR/grav_spee...

  

45 An Attempt to Prove the Motion of the Earth by Observations

By: Robert Hooke (1674), Fellow of the Royal Society.

*Senec. Nat. Qu. lib. I. cap. 30.

roberthooke.com/motion_of_the_earth_001.htm

www.roberthooke.org.uk/

www.bbc.co.uk/history/british/civil_war_revolution/hooke_...

  

46 “Dark Energy,88 Dark Matter87 & the Unknown Cosmos:”

www.youtube.com/watch?v=pHXv-NuSnP0

 

•Rhawn Joseph, Ph.D.

Astrobiology: The Origin of Life and the Death of Darwinism

www.brainmind.com/astrobiology.html

  

47 William Bryant Logan

Dirt: The Ecstatic Skin of the Earth

  

48 Leonard Susskind

See: String Theory

www.stanford.edu/dept/physics/people/faculty/susskind_leo...

 

The Cosmic Landscape: String Theory and the Illusion of Intelligent Design

www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/...

  

49 String Theory

www.damtp.cam.ac.uk/research/gr/public/qg_ss.html

superstringtheory.com/

wordnetweb.princeton.edu/perl/webwn

 

Unified Field Theory

www.pbs.org/wgbh/nova/elegant/everything.html

www.britannica.com/EBchecked/topic/614522/unified-field-t...

  

50 William Gilbert (1544-1603)

galileo.rice.edu/sci/gilbert.html

 

SAO/NASA Astrophysics Data System (ADS)

Title: Cosmology and the Magnetical Philosophy 1640-1680

Authors: Bennett, J. A. | William Gilbert

Journal: JOURNAL FOR THE HISTORY OF ASTRONOMY

V. 12, P. 165, 1981 (pp. 165-166) Bibliographic Code: 1981JHA....12..165B

adsabs.harvard.edu/full/1981JHA....12..165B

  

51 M Theory

wordnetweb.princeton.edu/perl/webwn

 

Elegant Universe | Nova

www.pbs.org/wgbh/nova/elegant/

   

52 Edward Witten

Superstring Theory: Volume 1 + 2, Introduction (Cambridge Monographs on Mathematical Physics)

 

Institute for Advanced Study

www.sns.ias.edu/~witten/

  

53 Brian Cox

Wonders of the Solar System, BBC:

•What on Earth is Wrong with Gravity? [DVD]

•Do You Know What Time It Is? [DVD]

www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/...

 

University of Manchester, School of Physics and Astronomy

www.manchester.ac.uk/research/brian.cox/

  

54 NASA | ESA | LISA | GOCE

 

•NASA: National Aeronautics and Space Administration: www.nasa.gov/

 

•ESA: European Space Agency: www.esa.int

www.esa.int/esaSC/SEMDYI5V9ED_index_0.html

 

•LISA: Laser Interferometer Space Antenna: lisa.nasa.gov/

 

•GOCE: Gravity-Mapping Satellite

www.guardian.co.uk/science/video/2009/mar/15/goce-gravity...

www.esa.int/SPECIALS/GOCE/SEMY0FOZVAG_0.html

  

55 Jim Schenk

What Does God Look Like in an Expanding Universe?

  

56 Dr. Wayne Dyer

www.drwaynedyer.com

  

57 Bashar | Darryl Anka

www.bashar.org

  

58 Richard Dawkins

The Selfish Gene

 

•The Genius of Charles Darwin [DVD]

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59 Girl Interrupted [DVD]

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60 The Intention Experiment

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61 Ronald Mallett

Time Traveler

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62 Walter Wangerin, Jr

The Four Acts of Prayer [DVD]

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63 Neale Donald Walsch

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64 Hyperspace | BBC (2002)

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65 Yes [DVD]

Sally Potter

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66 The Sedona Method

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67 Robert Tennyson Stevens

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68 Cesar Millan | Dog Whisperer

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69 Georges Brossard

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70 Joseph Campbell

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71 Joe Vitale

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72 Jack Canfield

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73 Rhonda Byrne

The Secret | The Power

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74 Gene Landrum

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75 Contrast

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www.google.com/dictionary?aq=f&langpair=en|en&q=Contrast+&hl=en

  

76 Theron Q. Dumont | William Walker Atkinson (1862-1932)

The Solar Plexus or Abdominal Brain [Public Domain]

  

77 The Moses Code [DVD]

www.themosescode.com

  

78 The Matrix [DVD]

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79 The Riches [DVD]

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80 Position BE = ACTING

 

•Darryl Hickman

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81Michael Bernard Beckwith

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82James Allen

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83Neville Goddard

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www.nevillelecturehall.com/

  

84 Stephan Martin

Cosmic Conversations: Dialogues on the Nature of the Universe and the Search for Reality

cosmicconversations.org/default.aspx

  

85Pheromones

www.google.com/dictionary?langpair=en|en&q=Pheromone&hl=en&aq=f

www.cals.ncsu.edu/entomology/schal_lab/ChemicalEcology

  

86Thermodynamics

www.google.com/dictionary?langpair=en|en&q=thermodynamics&hl=en&aq=f

puccini.che.pitt.edu/~karlj/Classes/CHE2101/

ecee.colorado.edu/~bart/book/book/chapter1/ch1_4.htm

  

87Dark Matter

wordnetweb.princeton.edu/perl/webwn

www.youtube.com/watch?v=nJN2X3NrQAE imagine.gsfc.nasa.gov/docs/science/know_l1/dark_matter.html

www.google.com/dictionary?langpair=en|en&q=Dark+Matter&hl=en&aq=f

  

88Dark Energy

www.google.com/dictionary?langpair=en%7Cen&q=Dark+Ene...

www.youtube.com/watch?v=pHXv-NuSnP0

  

89Black Holes

wordnetweb.princeton.edu/perl/webwn

www.google.com/dictionary?langpair=en|en&q=black+hole&hl=en&aq=f

curious.astro.cornell.edu/blackholes.php

www.pbs.org/wnet/hawking/strange/html/blackh.html

www.abc.net.au/pm/content/2004/s1159816.htm

 

www.google.com/search?q=Black+Holes&hl=en&prmd=iv...

univ&tbs=bks:1&tbo=u&ei=gxjnTOn4HY-usAOK7LSxCw&sa=X&oi=book

_group&ct=title&cad=bottom-3results&resnum=22&ved=0CKEBELADMBU

 

Leonard Susskind48

The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics

 

Stephen W. Hawking41

Hawking On the Big Bang and Black Holes

 

Stephen W. Hawking, Roger Penrose

The Nature of Space and Time

  

90Messenger Particles

www.google.com/dictionary?langpair=en|en&q=messenger+particle&hl=en&aq=f

www.pbs.org/wgbh/nova/elegant/glossary.html

  

91Spirals

www.physorg.com/news97227410.html

science.howstuffworks.com/environmental/life/evolution/fi...

www.mathematische-basteleien.de/spiral.htm

 

•PI: www.pithemovie.com/ [DVD]

  

92Quantum Nonlocality

www.braungardt.com/Physics/Quantum%20Nonlocality.htm

www.scientificamerican.com/article.cfm?id=nonlocality-fro...

  

93Multiverse

www.google.com/dictionary?aq=f&langpair=en|en&q=multiverse&hl=en

www.astronomy.pomona.edu/Projects/moderncosmo/Sean's%20mu...

  

94Magnetic Storm [DVD]

www.pbs.org/wgbh/nova/magnetic/

  

95TIME

www.time.gov

tycho.usno.navy.mil

www.haystack.mit.edu/geo/index.html

 

•Navstar Global Positioning System (GPS)

www.fas.org/spp/military/program/nav/gps.htm

  

96Cosmology

www.google.com/dictionary?langpair=en|en&q=Cosmology&hl=en&aq=f

  

97Darwin, Charles

The Origin of Species [Public Domain] pp. 512-520; 529

  

98Nisargadatta Maharaj

www.nisargadatta.net

  

99Posidonius (c.135–c.51 B.C) Greek

Sumpatheia: Cosmic Sympathy

en.wikipedia.org/wiki/Posidonius

encyclopedia2.thefreedictionary.com/Posidonius+of+Rhodes

www.google.com/dictionary?langpair=en|en&q=sympathy&hl=en&aq=f

  

100Nicholas Copernicus

De Revolutionibus Orbium Coelestium

On the Revolutions of the Heavenly Spheres

 

www.fordham.edu/halsall/mod/1543copernicus2.html

zebu.uoregon.edu/~soper/Orbits/copernicus.html

homepages.wmich.edu/~mcgrew/kuhn.htm

 

books.google.com/books?id=vFcqRuHLMwEC&printsec=front...