03 Patella ulyssiponensis. Length 40mm. North Yorkshire. September 2014.

Highest profile (H/L 34%) in sample of eighteen.

In profile, anterior and posterior slightly convex.

 

SPECIES DESCRIPTION part B BELOW

SPECIES DESCRIPTION part A flic.kr/p/BG8mKq

Key id. features 4Pu flic.kr/p/BG8hhs

OTHER SPECIES ALBUMS www.flickr.com/photos/56388191@N08/collections/

 

GLOSSARY below.

 

Patella_ulyssiponensis Gmelin, 1791

Identification of British patellid limpets.

With the exception of shells with height >50% of length (only P. vulgata grows that high, but many P. vulgata have low shells), shell-exteriors cannot be relied on, and shell-interiors can be confusing. Examination, in good light under magnification, of extended pallial tentacles on living animals is essential for consistent accurate discrimination of the three rock-dwelling Patella species. Best achieved with specimen adhering to underside of supported glass-sheet in black-based container of seawater.

Some morphologically intermediate forms can only be reliably identified by sequencing DNA or allozyme study. Intermediates result from similar environmental factors affecting different species in similar ways and are not hybrids (Sanna et al., 2011 and Sá-Pinto et al., 2007). For the purpose of recording for distribution schemes it is advisable to disregard intermediates unless DNA or allozymes can be employed, especially beyond or on the limits of known distributions. Intermediates most frequent near limit of distributions of P. depressa and P. ulyssiponensis in Isle of Wight , perhaps because conditions not optimal (Fretter and Graham, 1994).

 

Key identification features of typical British specimens.

 

Patella ulyssiponensis

1. Basal half of pallial tentacles has opaque pigment which can be white, off-white, cream or, on large specimens, yellowish or orange. The distal half fades to a translucent tip. Opaque basal half is often distinct from translucent mantle-skirt that they arise from, so it is possible to confuse with P. depressa. It is important to use pallial tentacles in combination with foot-colour/shell-length for identification. Examples at 26Pu flic.kr/p/BGqszN .

2. Foot that is NOT pitch-brown/black or dark khaki. It can be whitish when young 30Pu flic.kr/p/BGqk4q becoming yellowish 31Pu flic.kr/p/BGrKw1 and, sometimes, orange with age 21Pu flic.kr/p/AUuNww . Juveniles under 12mm length may show a blackish internal shadow through the thin pale translucent foot 30Pu flic.kr/p/BGqk4q as they lack gonads above the foot that mask the dark viscera in adults.

 

Similar species

 

Patella vulgata

Extremely variable species; foot colours and nearly all shell-features have overlaps with P. depressa and P. ulyssiponensis.

1. Pigment-less pallial tentacles are slender, translucent and same colour as mantle-skirt they arise from. 40Pu flic.kr/p/BPJ1vQ .

Cautions:

Pallial tentacles of P. vulgata may look white when arise from colourless mantle-skirt in some lighting, but no pigment 41Pu flic.kr/p/AUxuXs .

Translucency and fineness of pallial tentacles of P. vulgata often make discernment difficult, especially when mantle skirt retracted from shell-rim and pallial tentacles viewed against shell 42Pu flic.kr/p/BGtg3y ; often virtually invisible when out of water as may be retracted as well as highly translucent 43Pu flic.kr/p/AUDqUz .

Foot colour of P. vulgata varies greatly, sometimes orange resembling P. ulyssiponensis 53Pu flic.kr/p/BPKsw5.

Shell interior can be white or tinted orange in P. vulgata 53Pu flic.kr/p/BPKsw5 and 44Pu flic.kr/p/BPKJ6G .

 

Patella depressa

[1 & 2 in combination, not singly, are diagnostic of typical specimens but exclude intermediates.]

1. Pigmented pallial tentacles are opaque chalky-white for more than half of extended-length; may have translucent tip; distinctly whiter than buff mantle-skirt from which they arise 45Pu flic.kr/p/BJLMBx . Even when mantle-skirt retracted, pallial tentacles often clearly visible contrasting with the darker mantle 46Pu flic.kr/p/AUxm6u .

2. Sole of foot pitch-brown 47Pu flic.kr/p/AUDiJH to black 46Pu flic.kr/p/AUxm6u .

3. On shell-interior, whitish projecting points of ribs have short, unglazed, chalky, pure-white central line, but reduced or lacking where projecting points of ribs eroded 48Pu flic.kr/p/BS4e7v . [This feature recently recognised by S. Payne, and applies to all in large sample examined by IFS. Unsure yet if universal on P. depressa and exclusive of P. vulgata and P. ulyssiponensis.]

Caution:

Shell interior can be orange-cream in P. depressa 49Pu flic.kr/p/BixiVz

 

Patella caerulea Linnaeus, 1758.

Does not occur in Britain. In Iberia and Mediterranean, separation from it of some specimens of P. ulyssiponensis could not be achieved with foot colour and shell morphology by Sanna et al. (2011) who relied on the use of DNA sequencing. They did not mention attempting the use of pallial tentacle colour on live specimens; it may be worth investigation. See Sanna et al. for images of P. caerulea.

 

Habits and ecology

P. ulyssiponensis is a southern species which reaches its northern limit in south-west Norway and locally at cold winter-sea areas of Baltic, North Sea and north-east Irish Sea. It lives on rocky shores with Ballantine (1961) wave exposure scale 1- 4 or 5 where turbidity does not prevent algal growth. It is often the dominant species of limpet at mid- and low-tide levels on extremely and very exposed shores (scales 1 & 2). It can be common on exposed (scale 3) lower shores, and present on semi-exposed shores (scale 4) but largely confined to lower levels or to pools lined with encrusting calcareous algae at higher shore levels. On fairly sheltered (scale 5) shores it is absent or confined to pools. It is usually found on bedrock, not on shingle or loose boulders, and it extends into the sublittoral zone. It is unable to produce very large, thick, high-domed shells, like those of some P. vulgata 50Pu flic.kr/p/AUDcK8 , to resist desiccation on drained rock on upper shores. P. ulyssiponensis is reported to be a consistently homing species (Branch, 1981a); adults always after feeding-excursions seeking to return to same position where a deep home-scar can be developed when substrate is relatively soft encrusting calcareous algae 7Pu flic.kr/p/AUibCP . Differences in amount of opaque, white, porcelaneous material on interior of shells at different localities may be due differences in suitability of environment 15Pu flic.kr/p/AUm6kt . Locomotion by retrograde waves alternating on each side (ditaxic) of sole; muscles alternately compress/relax against blood trapped between them to create waves. Feeding: most frequently grazes on calcareous encrusting algae and Corallina, ingesting the algae and organic deposits on their surface. Grazing is facilitated by powerful muscles in large buccal mass, and by rust-coloured iron-reinforced teeth on long radula with plentiful replacements for worn teeth 36Pu flic.kr/p/AUvMhW . Length varies seasonally; shorter when wear of active feeding exceeds growth rate. Patella spp. wear out up to two rows of teeth per day (Sigel, 2008 ). About four rows of teeth are in contact with substrate during feeding; loose particles are retained by rim of surrounding jaw# and the licker 38Pu flic.kr/p/BJKboP which sweeps them up at the end of the radula stroke. Long coiled intestine compacts faeces (often yellowish from high lime content obtained from calcareous algae) 35Pu flic.kr/p/BivTv4 into firm faecal strings that will not contaminate gills in pallial groove; compensates for adults lacking hypobranchial gland to produce mucus to bind particles exiting from nuchal cavity. Cilia on roof of nuchal cavity and side of foot conduct faecal matter from anus in nuchal cavity to middle of right side 24Pu flic.kr/p/BS1DhR . Faeces and debris accumulate there until periodic sharp contraction of pedal-retractor muscle clamps shell down and forcefully flushes water and waste out of shell (Fretter & Graham 1962 & 1994). When limpets removed from rock, accumulated pile of faecal strings often found in position. Cilia also create inhalent water-current from left of head through nuchal cavity, where urogenital openings located, and thence carry excreta and ova/sperm to exterior. Colourless interior shell-layers may be stained orange by digestive gland when feeding on red algae in both P. ulyssiponensis 4Pu flic.kr/p/BG8hhs and P. vulgata 43Pu flic.kr/p/AUDqUz Predators reported to be able to dislodge P. vulgata shells probably take P. ulyssiponensis too; they include gulls (Larus spp.), oystercatchers (Haematopus ostralegus), crabs, starfish and rats. Nucella lapillus bores through the shell, usually to the pedal-retractor muscle where the adjacent viscera are accessible obliquely to its radula without having to bore through the thick amphora# shell-layers covering the viscera 51Pu flic.kr/p/AUDb42 . Boring takes several days, but is rewarded with a large food supply, providing the Nucella isn't dislodged before completion . Respiration: gill-cilia create gentle local inhalent respiratory water currents all around perimeter of animal from adjacent shell-rim onto gills, and exhalent currents below gills back to shell-rim 24Pu flic.kr/p/BS1DhR (Yonge & Thompson, 1976). Densely ciliated groove on stalk and rim of each gill-lamella catches and removes large particles of detritus that would clog gill (Fretter & Graham, 1994) 25Pu flic.kr/p/BGqt5A . Blood passes from viscera and foot via vessels through gaps in encircling pedal-retractor muscle 23Pu flic.kr/p/BGqwhs into gills for oxygenation, and thence into encircling efferent pallial vessel in mantle-skirt, which carries blood to left of nuchal cavity and through its roof to elongated heart behind left of cavity 52Pu flic.kr/p/BpVk1S for recirculation to head, foot and viscera (Fretter & Graham, 1994). On shells with thick porcellaneous interior layers, efferent pallial-vessel leaves a mark where it passes through gap in gills to enter nuchal cavity 1Pu flic.kr/p/BpzHx5 & 14Pu flic.kr/p/BpCkES . Breeding season varies geographically; June-September N.E. England, June-November S.W. England, and precise timing varies year to year (Fretter & Graham, 1994). External fertilization, so close proximity of sexes required for success. Sperm and ova shed into water column, ova individually. 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 planktonic-life, settling on lower shore and assuming limpet form. Spat, when 1mm long, have eight radiating ridges; P. vulgata has five ridges on right, four on left. P. depressa has ten (Fretter & Graham, 1994). Some move to mid-tide level when shell-length 5mm.

 

Distribution and status

Mediterranean, Black Sea and North-east Atlantic from Morocco to Shetland and Bergen, Norway (Høisæter, 2009). Not in the colder waters of a) the Baltic b) North Sea from Stavanger to Le Havre and from Flamborough to Beachy Head c) north-east of Irish Sea from Kircudbright or Dumfries to Anglesey.

GBIF map www.gbif.org/species/5190390 ; Belgian and Dutch records are from flotsam (Fretter & Graham, 1994, p.464) and records on Macaronesian islands are misidentified P. aspera Röding, 1798 (“note” at www.marinespecies.org/aphia.php?p=taxdetails&id=456570)

U.K. distribution map NBN species.nbnatlas.org/species/NHMSYS0021056398

 

Acknowledgements

I gratefully acknowledge Dr Sebastian Payne for information, discussion and help during shore-work. Any errors or omissions are the responsibility of the author.

 

Links and references

 

Akşit, D. & Falakil Mutaf, B. 2011. The external morphology of the gill of Patella caerulea L. (Mollusca: Gastropoda). Turk. J. Zool. 35(4) 603-606. Tübitak. Turkey. PDF contains SEM images of gill.

www.google.co.uk/search?q=patella+gill+ciliated+groove&am...

 

Backeljau, T. 1986. Lijst van de recente mariene mollusken van Belgie Koninklijk Belgisch Instituut voor Natuurwetenschappen, Brussels.

PDF at www.marinespecies.org/imis.php?module=ref&refid=4414

 

Barber, A.H., Lu, D. & Pugno, N.M. 2015 Extreme strength observed in limpet teeth The Royal Society.

rsif.royalsocietypublishing.org/content/12/105/20141326

 

Branch, G.M. 1981a. The biology of limpets. Oceangr. Mar. Biol. Ann. Rev. learning.watfordboys.org/mod/resource/view.php?id=4730

 

Branch, G.M. 1981b. The biology of limpets. Oceangr. Mar. Biol. Ann. Rev. www.google.co.uk/search?q=Patella+vulgata+blood+circulati...

 

Cohen, A.L. & Branch, G.M. 1992. Environmentally controlled variation in the structure and mineralogy of Patella granularis shells from the coast of southern Africa: implications for palaeotemperature assessments. Palaeogeography, palaeoclimatology, palaeoecology, 91: 49-57. www.whoi.edu/fileserver.do?id=163844&pt=2&p=36767

 

Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1849), London, van Voorst. (As Patella athletica; PDF at archive.org/stream/historyofbritish02forb#page/424/mode/2up Use slide at base of page to select pp.425-429.)

 

Fretter, V. and Graham, A. 1962. British prosobranch molluscs. London, Ray Society.

 

Fretter, V. and Graham, A. 1994. British prosobranch molluscs. Revised and updated edition. London, Ray Society.

 

Gmelin, J.F. (1791) Vermes. In Gmelin J.F. (Ed.) Caroli a Linnaei Systema Naturae per Regna Tria Naturae, Editio Decima Tertia, Aucta Reformata. Tome 1, Pars 6 (Vermes). G.E. Beer, Lipsiae [Leipzig], pp. 3021-3910., available online at www.biodiversitylibrary.org/item/83098#5 Original description on p.692 of PDF .

 

Goshima, S., Ilano, A.S., Ito, A. & Nakao, S. 2002. Seasonal and tidal-height variations in body weight and radular length in Nodilittorina radiata (Eydoux & Souleyet, 1852). J. Mollus. Stud. 68: 197-203.

PDF at mollus.oxfordjournals.org/content/68/3/197.full.pdf+html

 

Graham, A. 1988. Prosobranch and pyramidellid gastropods. London.

 

Høisæter, T. 2009. Distribution of marine, benthic, shell bearing gastropods along the Norwegian coast. Fauna Norvegica 28: 5-106.

pdf at www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/563

 

Jeffreys, J.G. 1862-69. British conchology. vol. 3 (1865). London, van Voorst. (As Patella vulgata var. 4 depressa, incorrectly attributed to Pennant.); Free PDF at archive.org/stream/britishconcholog03jeff#page/236/mode/2up . Use slide at base of page to select pp.237.

 

MacClintock, C. 1967. Shell structure of patelloid and bellerophontid gastropods (Mollusca). Peabody Museum of Natural History, Yale University. Bulletin 22. pdf at

www.google.co.uk/?gws_rd=ssl#q=MacClintock%2C+C.+1967.+Sh....

215 pages, may take a few minutes to download. Contents on page v.(= p.6 of pdf). To find pages on pdf add 1 to Roman numerals, and add 11 to modern numerals.

 

Pennant, T. (1777). British Zoology, vol. IV. Crustacea. Mollusca. Testacea. London. i-viii, 1-154, pls. 1-93.,

Page 142 biodiversitylibrary.org/item/127011#page/168/mode/1up

Pl. 89 fig.146. biodiversitylibrary.org/item/127011#page/361/mode/1up

 

Sanna, D., Dedola, G. L., Lai, T., Curini-Galletti, M. & Casu, M. 2011. PCR-RFLP: A practical method for the identification of specimens of Patella ulyssiponensis s.l. (Gastropoda: Patellidae), Italian Journal of Zoology,

pdf at www.researchgate.net/publication/233126771_PCR-RFLP_A_pra...

 

Sá-Pinto, A., Branco,M., Harris, D.J. & Alexandrino, P. 2005. Phylogeny and phylogeography of the genus Patella based on mitochondrial DNA sequence data. J. Exp. Mar. Biol. Ecol. 325: 95-110.

 

Sá-Pinto, A., Alexandrino, P. & Branco,M. 2007. High genetic differentiation with no evidence of hybridization between four limpet species (Patella spp.) revealed by allozyme loci. Scientia Marina 71(4): 801-810. Barcelona. pdf at www.vliz.be/imisdocs/publications/131981.pdf

 

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=140684

 

GLOSSARY

 

amphora – (on interior of limpet shell) Roman amphora-shaped area enclosed by scars of pedal-retractor muscle and anterior mantle-attachment.

 

anteroposterior – (of linear feature) aligned from anterior to posterior.

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

apex - earliest formed part of a gastropod shell, the summit of the cone. (In this limpet-account restricted to the exterior of the shell, and “vertex” used for the interior.)

 

auct. - (abbreviation of “auctorum” = “of authors”) name, often of another valid species, used in error for this one by other author(s). en.wikipedia.org/wiki/Auctorum

 

cephalic – (adj.) of or on the head.

 

cilia – (pl.) microscopic linear extensions of membrane that move in rhythmic waves to create locomotion, or move particles and liquids e.g. inhalent water currents. (“cilium” singular). (Electron scanning microscope image at flic.kr/p/qQB5zj )

 

ciliary – (adj.) relating to or involving cilia.

coll. – in the collection of (named person or institution) (compare with legit).

conoid – shaped like a cone.

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).

 

epithelium – membranous covering of internal and external surfaces of animal's body, e.g. skin and lining of tubes and cavities.

 

head scar – term used by many British authors for patch of different shell-material, and often different colour, near vertex of interior of limpet shell; misnomer as the mobile head, free of any attachment to the shell or mantle-roof of the nuchal cavity cannot make a scar. A preferable term is “vertex patch”.

 

height – (of limpet) perpendicular distance from apex to plane of aperture-rim (best measured with callipers).

 

hyaline shield – transparent sheet of chitin at anterior of radula that rests on bolsters of odontophore; attachment point for retractor muscles of radula; helps guide food particles into mouth.

 

jaw - unarticulated chitinous structure that encloses inner lips of Patella spp. at sides and anterior.

legit – (abbreviation; leg.) collected/ found by (compare with coll.)

licker - cuticularized structure with plate-like ridges and deep transverse grooves at tip of radula of Patella spp.; retains and sweeps up food particles.

 

Macaronesia – Madeira, Canary Islands, Cape Verde Islands and Azores.

 

mantle – sheet of tissue covering visceral mass of molluscs. Secretes shell of shelled species, and forms part or all of dorsal body surface (notum) of those without shells. (See mantle skirt.)

 

mantle skirt – extension on gastropods of mantle proper as a flap roofing a cavity containing gills, genital and renal openings, anus etc. On limpets, skirt and cavity extend around periphery of animal.

 

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).

nuchal – (adj.) of nape of the neck.

nuchal cavity – cavity roofed by mantle skirt that contains head of limpet; part of mantle cavity (remainder consists of pallial groove on each side of body).

 

ovoid – egg-shaped, (as a solid or in outline).

ovate – egg-shaped, (as a solid or in outline).

 

pallial groove band – shell material deposited on interior of shell by strip of black mantle roofing the pallial groove that contains the gills. On British Patella spp. it is often clouded-white.

 

pedal retractor muscle – strong muscle that retracts foot into shell of most gastropods, but on limpets is used to clamp shell to substrate, a.k.a. “foot muscle”.

 

porcellaneous – resembling vitreous glazed ceramic material.

 

retrograde - (of locomotion waves on foot) waves travel from anterior to posterior.

scar – mark on shell made by attachment point of muscle or other body part.

 

skirt shell layer - shell material deposited on interior of shell by mantle skirt. On British Patella spp. colourless when deposited, and clouded white, or transparent showing the colours of the outer layer. Crystalline structure causes short lines of blue iridescence parallel to the aperture rim on all four British species of Patella when the light is right.

 

tricuspid - (of tooth) having three points.

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.

 

unicuspid - (of tooth) having a single point.

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

 

vertex – angle at highest point on interior of limpet-shell. [Synonym of “apex”, chosen (by IFS) to help avoid confusion with the highest point, apex, on the exterior. In classical Latin “vertex” was used for the “pole of the heavens”, obviously only seen from below.]

 

vertex patch –layer of different shell-material, and often different colour, at vertex of interior of limpet shell. (See “head scar”.)

Done