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The Annual Snow Geese migration started last weekend when thousands of these beautiful birds landed just outside Vancouver for their only stop on their way from Alaska to California.
They turn the farmers fields into very noisy blankets of snow
Susan Wood
Title: Professor of Art History
Degrees
Ph.D. Columbia University, New York, NY
Major Fields
Ancient Roman sculpture, portrait sculpture, sarcophagi, and luxury objects
with relief decoration, all from 1st century B.C.E. -- 3rd century C.E.
Publications
Imperial Women: a Study in Public Images, 40 B.C. - A.D. 68. Brill: Leiden,
1999. 2nd edition, paperback, 2000.
Roman Portrait Sculpture, A.D. 217-360: the Transformation of an Artistic
Tradition, Vol. 12 of Columbia Studies in the Classical Tradition. Leiden:
Brill, 1986.
Articles
Sarcophagus, Encyclopedia of Sculpture, Chicago: Fitzroy-Dearborn, 2004,
1516-1521.
Literacy and Luxury: A Papyrus-scroll Winding Device from Pompeii,
Memoirs of the American Academy in Rome XLVI,2001, 23-40. Also
presented as a poster-session at the annual meetings of the AIA/APA,
January 4, 2003.
Mortals, Empresses and Earth Goddesses: Demeter and Persephone in Public
and Private Apotheosis, I Claudia II: Women in Roman Art and Society.
Papers from the Colloquium. Austin: University of Texas Press, 2000, 77-99.
Oral version presented November 2, 1996, at a colloquium at Yale University
Art Gallery.
Goddess or Woman? Bryn Mawr College Alumnae Bulletin, Fall, 1999, 9-12.
Forgotten Women in the Roman Imperial Portrait Group at Béziers,
Archaeological News 21-22 (1996-97), 1-19, also presented at the annual
meetings of the Midwest Art History Society, March 29, 1996 and at the
annual meetings of the AIA/APA, December, 1996.
Diva Drusilla Panthea and the Sisters of Caligula, AJA 99 (1995),
457-482, presented under title of "Sisters and Mothers of Tyrants," at the
annual meetings of the A.I.A./A.P.A., December, 1994.
Alcestis on Roman Sarcophagi - Postscript, Roman Art in Context: an
Anthology, ed. Eve D'Ambra, Prentice Hall: Englewood Cliffs, N.J., 1993,
96-103.
Messalina, Wife of Claudius: Propaganda Successes and Failures of his Reign,
JRA 5 (1992) 221-234.
Memoriae Agrippinae: Agrippina the Elder in Julio-Claudian Art and Propaganda,
AJA 92, 1988.
Isis, Eggheads and Roman Portraiture, JARCE 24, 1988.
Child Emperors and Heirs to Power in Third Century Roman Portraiture,
Ancient Portraits in the J. Paul Getty Museum I: Occasional Papers on
Antiquity 4, 1987.
A Too-Successful Damnatio Memoriae : Problems in Roman Portraiture of the
Third Century, AJA 87 (1983).
The Bust of Philip the Arab in the Vatican: a Case for the Defense, AJA 86 (1982).
An Enigmatic Roman Portrait, Cleveland Museum of Art Bulletin,
LXVIII,No. 8, Oct. 1981.
Subject and Artist: Studies in Roman Portraiture of the Third Century,
AJA 85 (1981).
Alcestis on Roman Sarcophagi, AJA 82 (1978), reprinted with postscript in
Roman Art in Context , 1993, 84-103.
Book Reviews:
Representing Agrippina:Constructions of Female Power in the Early Roman
Empire, by Judith Ginsburg, ed. Eric Gruen, American Philological Association,
2005, forthcoming in Journal of Roman Archaeology 2007 or '08.
Cleopatra and Rome, by Diana E.E. Kleiner, Massachusetts and London:
Belknap Press, 2005, The New England Classical Journal, 33.3, August 2006, 237-240.
Mit Mythen Leben: Die Bilderwelt der römischen Sarkophage, by Paul Zanker
and Bj r rn Christian Ewald, Bryn Mawr Classical Review 2004.11.22.
Death and the Emperor, by Penelope Davies, Cambridge: Cambridge University
Press, 2000, Bryn Mawr Classical Review 00.12.08.
Agrippina: Sex, Power and Politics in the Early Empire , by Anthony A. Barrett,
New Haven, 1996, Bryn Mawr Classical Review 97.3.11.
Antonia Augusta, Portrait of a Great Roman Lady , by Nikos Kokkinos, London,
1992, American Journal of Numismatics 7-8 (1995-96) 293-98.
Porträtreliefs stadtrömischer Grabbauten , by Valentin Kockel, Beiträge zur
Erschließung hellenistischer und kaiserzeitlicher Skulptur und Architektur
Vol. 12, ed. Klaus Fittschen and Paul Zanker, Mainz am Rhein: Verlag
Philipp von Zabern, 1993, Archaeological News 20, 1995 .
Griechische und Römische Kolossalporträts bis zum späten ersten Jahrhundert
n.Chr, by Detlev Kreikenbom, JdI E-H 27 (Berlin and New York, 1992),
forthcoming in AJA 98 (1994).
Ancient Portraiture: Image and Message , ed. Tobias Fischer-Hansen, John Lund,
Marjatta Nielsen and Annette Rathje, Acta Hyperborea 4, Copenhagen 1992,
AJA 97 (1993) 811-812.
Roman Art from Romulus to Constantine , by Nancy H. and Andrew W. Ramage,
Cornell University Press: New York, 1991, AJA 96 (1992) 773-774.
Roman Portraits, by Richard Daniel de Puma, exh. cat., University of Iowa Museum
of Art, 10 Sept. - 30 Oct. 1988, AJA 94 (1990).
Aion in Merida und Aphrodisias , by Andreas Alfoldi, AJA 87 (1983)
Roman Portraits: Aspects of Self and Society, First Century B.C. - Third
Century A.D. , by K. Patricia Erhart, Jiri Frel and Sheldon Nodelman, Art Bulletin,
LXIV (1982).
Selected Public Lectures
An Obscure Family Without Ancestral Images,' or, How to build a dynasty from
scratch, presented at the symposium The Miller Collection of Roman Sculpture,
Intentions and Acquisitions, Minneapolis Institute of Arts, April 17, 2004.
The Incredible, Vanishing Wives of Nero, presented in the colloquium Tyranny
and Transformation, Emory University, Oct. 2000, and in the Peter Wall Seminars,
University of British Columbia, Vancouver, Jan. 28, 2002. Also presented for the
Archaeological Institute of America Visiting Lecturer program at Gainesville, FL.,
October 18, 2005; Tampa, FL, October 19, 2005; and Valparaiso, IN, October 25, 2005.
The Wives of Nero: Public Images on Provincial Coinage, presented at the annual
meetings of the American Philological Association and the Archaeological Institute
of America, Jan. 5, 2002. Abstract: American Journal of Archaeology
Mass Produced Art, an Oxymoron? -- The Case of the Roman Imperial Portrait,
presented 12/29/91 at the annual meeting of the AIA, abstract published
AJA 96 (1992) 349.
High Fashion and Classical Reference: Coiffures of Roman Imperial Wome
from Augustus to Hadrian, presented at the annual meeting of the AIA, 1989,
in a colloquium: "The Role of Costume in Roman Art." Abstract: AJA 94 (1990).
Memoriae Agrippinae: Agrippina the Elder in Julio-Claudian Art and Propaganda,
presented 12/28/86 at the session of the Women's Classical Caucus at the
AIA/APA convention.
Exhibitions
Diva Augusta: Images of Imperial Women in Roman Art, exhibition of coins
and sculpture, Sackler Museum, April 19, 1986-December, 1986.
Collaborated with Professor Ernst Badian on a small exhibition of Roman coins
of the late republic and early empire, spring of 1983.
Courses Taught
Greek Art, Roman Art, Art of the Near East, Critical Thinking and Writing in Art History
If you are interested in Julio Claudian Iconography and portrait study you may enjoy these two links:
Julio Claudian Iconographic Association- Joe Geranio- Administrator at groups.yahoo.com/group/julioclaudian/
The Portraiture of Caligula- Joe Geranio- Administrator- at
Both are non-profit sites and for educational use only.
Streamlined juveniles on Laminaria hyperborea frond, orientated with prow-like anteriors probably facing from whence wave or current impact comes. The width of the blue lines remains fairly constant at 0.1mm to 0.2mm at all growth stages. These juveniles also have a variable number of red-brown rays interspersed between the blue ones, but this is a more frequent feature on adults in holdfasts; Graham & Fretter (1947) only found red-brown rays on a juvenile once in a study of 684 shells. Radula marks on the frond suggest that the limpets swing their heads in an arc as they feed.
A dark chestnut band on the distal face of the horseshoe-shaped pedal-retractor muscle can be seen through the translucent shells of four of these juveniles.
Concise Key id. features: 1Pp flic.kr/p/Z4FxDe
Part 1, SHELL FORMS: 2Pp flic.kr/p/Z4FxAi
Part 2, BODY & ANATOMY, BELOW.
Part, 3 HABITS & ECOLOGY: 4Pp flic.kr/p/Z4Fx9M
Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/
PDF available at www.researchgate.net/publication/346673416_Patella_pelluc...
GLOSSARY below.
Body description (Features visible on live animal.)
The main flesh colour is white or yellowish white. A horseshoe-shaped series of strong muscle bundles make up the pedal-retractor muscle 53Pp flic.kr/p/Z6REoG & 54Pp flic.kr/p/C3widA . Juveniles have a distinct, longitudinal, dark chestnut band on the distal face of the pedal-retractor muscle that can often be seen through the translucent juvenile shell 3Pp flic.kr/p/Z4FxtK , 4Pp flic.kr/p/Z4Fx9M & 5Pp flic.kr/p/YNrZYJ or by dissection 55Pp flic.kr/p/Z6RDUW . The chestnut band fades on adults inside holdfasts 56Pp flic.kr/p/Y8tL5H . Some of the adults on fronds retain a strongly pigmented band 57Pp flic.kr/p/Z6RDtf & 22Pp flic.kr/p/Z51FP4 , but others lose it 58Pp flic.kr/p/C3wgX9 . Although the band fades on holdfast dwellers, the anterior dorsal surface of the foot, below the head, usually becomes yellowish with brown creases. This colouration may extend faintly over more of the foot dorsally 53Pp flic.kr/p/Z6REoG . The head has short stout snout occupied by a large mouth surrounded by thick, white, wrinkled outer lips 59Pp flic.kr/p/Z6RCRd which extend the snout when protruded 60Pp flic.kr/p/Y8tJDM . A pink, internal odontophore and buccal mass can be seen through the translucent, white head 61Pp flic.kr/p/Z6RCAJ . The odontophore is separated from the outer lips by dull orange inner lips that open laterally and close to a vertical line 62Pp flic.kr/p/Z6RCAJ . When they open, the radula with rust-coloured, iron-rich teeth is protruded through the arch of the opaque white jaw 60Pp flic.kr/p/Y8tJDM . The tapered, translucent white cephalic tentacles each have a black eye with a tiny opening on the dorsum of the slightly swollen tentacle-base 61Pp flic.kr/p/Z6RCAJ . The opening is at the apex of an internal cone of black pigment that, because visible through the translucent flesh, gives the false impression of a larger opening. 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-skirt is translucent whitish, often showing the colour of underlying shell when viewed ventrally 63Pp flic.kr/p/Y4Rjnb . The mantle cavity consists of a nuchal cavity over the head 64Pp flic.kr/p/C3wfCW and a groove, containing pallial gills, around the periphery of foot but, unlike other British Patellidae, not around the anterior of the head 65Pp flic.kr/p/Y8tH2Z . The gill-less anterior gap appears (small sample) to be proportionally of greatest extent on juveniles 66Pp flic.kr/p/C3wf4Q . A red (vestigial?) osphradium is located within the nuchal cavity next to each terminal bundle of the pedal-retractor muscle Pp53 flic.kr/p/Z6REoG . The efferent pallial vessel, less whitish than the rest of the mantle skirt, runs around the entire animal at the base of the pallial gills 65Pp flic.kr/p/Y8tH2Z and in front of the head to a point left of the head where its two ends unite in a trunk 64Pp flic.kr/p/C3wfCW that passes through the roof of the nuchal cavity to the heart. The mantle skirt is fringed with translucent, white pallial tentacles that can protrude beyond the rim of the shell when the mantle is fully extended 67Pp flic.kr/p/Y8tGwv . Along the whole length of each side of the dorsal surface of the foot there is a lateral glandular streak 53Pp flic.kr/p/Z6REoG with an overhanging upper lip. The lip has lobe-like retractile tentacles 68Pp flic.kr/p/Z6RA7A and is usually paler than the rest of the foot when the latter is tinted yellowish.
58Pp flic.kr/p/C3wgX9 . The sole is pure white on juveniles and early adults on fronds, often becoming yellowish, especially at the anterior, on frond dwelling, large adults 69Pp flic.kr/p/Y8tEYF . Adults in holdfasts have white soles even when the dorsal surface of the foot is yellowish with brown creases 65Pp flic.kr/p/Y8tH2Z
The intensity of colour on coloured soles is diminished when the sole is expanded laterally 70Pp flic.kr/p/Z9Bf6x . The anterior of the foot is bilaminate with the dorsal lamina extending beyond the sole 59Pp flic.kr/p/Z6RCRd . The anterior-pedal mucous gland is between the laminae. As with other patellids, there is no penis as fertilization is external.
Internal functional anatomy
When the body is removed from the shell the entire mantle is visible. The peripheral mantle-skirt is white translucent and may reveal the white foot below 71Pp flic.kr/p/Zjfznw . The rest of the mantle is semi-transparent with a fine spray of black pigment of varying intensity. Many features of the viscera can be discerned through it.
Blood circulation and respiration
Image 72Pp flic.kr/p/YhjbgA illustrates paragraph 1.
After it has oxygenated organs in the visceral mass, the colourless blood, depleted of oxygen, collects in visceral sinuses. It then passes in vessels through gaps in the pedal-retractor muscle into an afferent branchial vessel that runs through the mantle skirt around the edge of the distal face of the muscle . The afferent branchial vessel distributes blood to all the gill leaflets which re-oxygenate it as it passes through them. The oxygenated blood passes into a large efferent pallial vessel (a.k.a. efferent branchial vessel) and passes forwards on both right and left sides of the animal. The
flow of blood in the efferent pallial vessel (e.p.v.) on the right continues round the front of the head to join the left of the e.p.v. in a trunk that enters the left side of the nuchal cavity to connect with the heart in the pericardial cavity behind the left of the nuchal cavity 55Pp flic.kr/p/Z6RDUW & 73Pp flic.kr/p/Zjfz8y . The heart consists of three parallel chambers; the auricle, ventricle and bulbous aorta. Blood is pumped out via the bulbous aorta to oxygenate organs in the head and visceral hump before returning to the visceral sinuses to recommence the cycle.
The gills consist of a large number of leaflets, alternating large and small, hanging from the roof of the pallial groove 74Pp flic.kr/p/YhjaWs . The leaflets vary in shape with free ends that can be rounded, flat or pointed, but all narrow where they attach to the roof of the pallial groove and have a deep and densely ciliated groove around the rim 75Pp flic.kr/p/YhjaS9 . The respiratory inhalant water current is created by the motion of cilia on each leaflet of the gills drawing water in all around the shell, except at the gill-less anterior (X5000 scanning electron microscope images of cilia on a chiton at flic.kr/p/qQB5zj ). Sediment entering with the water is trapped by mucus from the lateral glandular streak 53Pp flic.kr/p/Z6REoG and carried forwards and out by the exhalant current along the pallial groove. The oxygen-bearing water is drawn across the surface of the leaflets in the opposite direction to the blood flow within, so creating a counter current-system (Fretter and Graham, 1994). The dense cilia in the rim-groove are reported (Fretter and Graham, 1994) to propel debris particles caught on the leaflet surface to the free end where they drop off, but this would seem unlikely for those in holdfasts feeding upside down into the core of the stipe. After passing the leaflets, the current, now exhalant, is propelled by cilia forwards along the pallial groove to exit the gill-less anterior on the right of the animal 76Pp flic.kr/p/ZjfytY & 77Pp flic.kr/p/YhjaDJ . It is unlikely that the red features referred to as the osphradia 53Pp flic.kr/p/Z6REoG have the usually attributed function of water-quality testing as there are no associated ctenidia to forwarn, and they are located in the path of the exhalant water after it has flowed over the pallial gills and shortly before it exits the anterior of the shell. There are anatomical signs that they may be vestiges of a lost double osphradium-ctenidium complex like that still found in Diodora graeca flic.kr/p/neENxW (Spengel, 1881, in Fretter & Graham, 1962, p314). Graham & Fretter (1947) had a 'suspicion' that the leaflets on frond-dwellers are smaller than those on holdfast-dwellers, and that this can be correlated with the greater exposure to water movement of frond dwellers. This seems to be supported by some images 78Pp flic.kr/p/Zjfyby that show large leaflets projecting from the shell of holdfast dwellers, but no leaflets projecting from the shell of frond dwellers. But, measurement of live, expanded, gill area is difficult, and individuals can extend or retract the mantle and gills.
Alimentary and excretory features .
The inner lips of the mouth, described above, open into the buccal cavity. 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 60Pp flic.kr/p/Y8tJDM . 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 pink odontophore 61Pp flic.kr/p/Z6RCAJ & 79Pp flic.kr/p/Zjfxp3 consisting of a right and left bolster which is covered in thick cuticle. Much of a bolster is made of strong cartilage-like material. The odontophore occupies a large amount of the body, 25% of its length. There is a black mark within its anterior half that is visible through the dorsal surfaces of it 80Pp flic.kr/p/ZjfxcQ , the epithelium of the head and the overlying mantle 81Pp flic.kr/p/ZjfwMb , and, on many translucent shells, it underlies and adds to the intensity of a patch of black pigment on the anterior of the shell's interior 82Pp flic.kr/p/ZjfwtL .
The radula is created in a semi-translucent sac 83Pp flic.kr/p/ZjfwgS . Its exposed anterior, widened into a hyaline shield 84Pp flic.kr/p/Zjfwaj , rests on the dorsum of the odontophore 85Pp flic.kr/p/Zjfw5u . The strong, iron-impregnated, unarticulated teeth are firmly fixed in a backwardly inclined position on the radula 86Pp flic.kr/p/ZjfvYC , but the anterior tip of the radula bends over the front of the odontophore so that the front rows of four teeth are inclined forwards like a chisel 85Pp flic.kr/p/Zjfw5u . To feed, the strong muscles of the large 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 60Pp flic.kr/p/Y8tJDM . When applied to Laminaria, the teeth effectively chisel into the tough frond or stipe, 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 60Pp flic.kr/p/Y8tJDM . Like other limpets and some sea snails that graze rock surfaces, P. pellucida has a long, powerful radula, but it is shorter than most, being about 75% the length of the shell 37Pp flic.kr/p/XQh5nv , requiring only a single fold to fit it inside the body 87Pp flic.kr/p/ZjfvNs which is about the same length as it 80Pp flic.kr/p/ZjfxcQ . Other British patellids have radulae between about 100% and 250% of shell length (Fretter & Graham, 1962). 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, so less length/time would be needed to form a radula for grazing alga that is tough, but not as hard as rock. Tooth creation starts at the slightly bifid, white, inner end of the radular sac 83Pp flic.kr/p/ZjfwgS 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 the radula emerges from the sac onto the odontophore 85Pp flic.kr/p/Zjfw5u .
The yellow digestive gland 55Pp flic.kr/p/Z6RDUW & 81Pp flic.kr/p/ZjfwMb composed of a mass of tubules is usually the most obvious organ on the surface of the visceral mass when the shell is removed. 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. Food material passes along the long coiled intestine which is usually white like the consumed white inner parts of Laminaria 81Pp flic.kr/p/ZjfwMb & 87Pp flic.kr/p/ZjfvNs . Faecal boluses pass through the rectum 81Pp flic.kr/p/ZjfwMb and are compressed and bound with mucus to emerge as faecal rods 88Pp flic.kr/p/ZjfvsN from the anus at the rear right of the nuchal cavity 87Pp flic.kr/p/ZjfvNs and are conveyed to, and expelled from, the right anterior of the shell by cilia and the flow of exhalant water 77Pp flic.kr/p/YhjaDJ . Compression of faeces assists removal without fouling the gills. Excreta from the nephridipores by the anus are expelled by the same route. Particulate matter removed by cilia on the gill leaflets, and sediment caught in mucus from the lateral glandular streak, are conveyed along the pallial groove by cilia and exhalant water, to join the anterior expulsion.
Reproductive organs
The gonads are situated between the viscera and foot. During the breeding season, they may spread over much of the viscera 87Pp flic.kr/p/ZjfvNs & 89Pp flic.kr/p/Zjfvq3 , but on juveniles , and on adults out of breeding condition, they are usually hidden or nearly so 55Pp flic.kr/p/Z6RDUW & 82Pp flic.kr/p/ZjfwtL , on an animal removed from the shell. Female ovaries are granular, and male testes have numerous interconnected tubules. Fertilization is external, so the male has no penis. Gametes leave both sexes through the right nephridium (kidney) via its nephridipore at the rear right of the nuchal cavity, and carried from the shell by cilia and the forward flowing exhalant current.
GLOSSARY
afferent (adj. of vessel) = carrying blood etc. towards an organ.
aperture = mouth of gastropod shell; outlet for head and foot.
apex (definition for this account) = position of the larval protoconch (see summit).
branchial (adj.) = of or relating to gills (branchiae).
cephalic = (adj.) of or on the head.
cnidocytes = explosive stinging cells of hydroids, jellyfish, sea anemones etc. en.wikipedia.org/wiki/Cnidocyte
ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.
efferent (adj. of vessel) = carrying blood etc. away from an organ.
ELWS = extreme low water spring tide (usually near March and September equinoxes).
epizoic (of a plant or animal) = growing or living non-parasitically on the exterior of a living animal.
GS1, GS2 etc. = Growth Stage 1 (planktonic veliger larva), Growth Stage 2 (newly settled juvenile) etc.
GS5f = Growth Stage 5 (late adult) living on Laminaria frond.
GS5h = Growth Stage 5 (late adult) living in Laminaria holdfast.
GS5s= Growth Stage 5 (late adult) living on Laminaria stipe.
haemocoel = system of interconnected spaces (sinuses) containing blood within body of a mollusc.
holdfast = rootlike in appearance, but not in function, tendrils attaching seaweed to the substrate. (a.k.a. hapteron).
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).
osphradium (pl. osphradia) = organ for testing water quality (chemical and/or for particles) usually near approach of inhalant current to ctenidium or pallial gills. Structure varied; including comblike, papillate or ribbing.
pallial (adj.) = of, relating to, or produced by the mantle (pallium).
periostracum = thin horny layer of chitinous material often coating shells.
phylogenetic (of development) = of change due to genetic make up.
resorb = absorb again that which was previously produced.
resorption = the process of absorbing again that which was previously produced.
stipe = stem of some brown seaweeds that supports the fronds and may contain a core of cells that transports sugars and nutrients within the alga.
summit (definition for this account) = highest point of the shell above the substrate (see apex).
trochophore = spherical or pear-shaped larva that moves with aid of girdle of cilia that beat to cause rotation. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for patellid limpets, most Trochidae and Tricolia pullus, and, with no veliger, chitons.
veliger = shelled larva of marine gastropod or bivalve mollusc which feeds and swims by beating cilia of a velum (small on P. pellucida).
I was walking through Sails pavilion, started to take their picture, and they shouted "Flash!" and motioned me to join them.
Juvenile (GS3) in pit eaten into Laminaria stipe. A dark chestnut band on the distal face of the horseshoe-shaped pedal-retractor muscle can be seen through the translucent shell.
Concise Key id. features: 1Pp flic.kr/p/Z4FxDe
Part 1, SHELL FORMS: 2Pp flic.kr/p/Z4FxAi
Part 2, BODY & ANATOMY: 3Pp flic.kr/p/Z4FxtK
Part, 3 HABITS & ECOLOGY, BELOW.
Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/
GLOSSARY below.
Habits and ecology
Occurs on rocky shores, usually where Laminaria is present. Some wave action or current is preferred; it is often scarce or absent on extremely sheltered shores. It may occur in holdfasts on exposed shores where few, if any, can be found on fronds in some months. A current of 1.3 m/s (2.9 km/h) was found to be optimal for those on Saccorhiza fronds at Loch Hine, Eire, with a marked decline in numbers at lower and higher speeds (Ebling, 1948, in Kain & Svendsen, 1969), but it is difficult to be precise as other factors such as depth and competition for space by encrusting epibiota on the fronds can affect numbers. Depth limits are LWST to, presumably, the depth where Laminaria growth ceases, but presence/frequency within that zone varies. In the Isle of Man, the percentage of occupied holdfasts of large L. hyperborea was about 50% at 1m below LWST [where wave action is strongest], less than 10% at 11m and 0% at 20m (Kain & Svendsen, 1969), but abundance is affected by the interplay of other factors, including whether the local population utilizes holdfasts or, as in Norway, not.
Occurs and feeds primarily on Laminaria spp. and Saccorhiza and, when young, on diatoms etc caught on the surface of Laminaria 3Pp flic.kr/p/Z4FxtK . Newly settled juveniles, less than 4mm long, feed on small red algae, such as Rhodymenia palmata, and on calcareous red algae encrusting rocks 2Pp flic.kr/p/Z4FxAi . Other plants sometimes eaten, mainly by juveniles, include Alaria, Himanthalia 90Pp flic.kr/p/Z3ib4q and Fucus serratus 91Pp flic.kr/p/ZmLpYy (Wigham & Graham, 2017). It is uncertain whether these foodplants are adequate for development as adults are only occasionally found on them. They may be those that have failed to reach Laminaria or have been swept off it by storms 95Pp flic.kr/p/CYbTbS . The hard iron-mineralized teeth of the radula 86Pp flic.kr/p/ZjfvYC , about 75% length of shell 80Pp flic.kr/p/ZjfxcQ , enables larger specimens to eat, and excavate caves in, the base of a Laminaria stipe 92Pp flic.kr/p/ZmLoEm .
Defence: When on Laminaria fronds or stipes, the translucent juvenile shells show the colour of the underlying alga and the dark chestnut band on the muscle. This, and the brown shell-colour of adults, is cryptic when on brown algae, except for the iridescent blue/green rays 3Pp flic.kr/p/Z4FxtK . The colour of the rays is created by the light interference of zig-zag lamellae of calcite selectively reflecting blue/green in water. Saturation of the blue/green is intensified, and contrast with the visible white body within the shell is increased, by black, non-crystalline, colloidal particles underlying parts of the rays (Li et al., 2015) 17Pp flic.kr/p/YNK8Wo & 19Pp flic.kr/p/Z4Y4Cv . If the shell is rotated, different lines appear and disappear as the light's angle of incidence on them changes (Li et al., 2015, “supplementary movie1” at www.nature.com/articles/ncomms7322#supplementary-information ). Flashing on and off of the rays as the Laminaria waves about and changes the angle of light incidence, may distract from the animal's outline, or it may camouflage by resembling neighbouring iridescent weeds such as Chondrus crispus 93Pp flic.kr/p/ZmLnQA and en.wikipedia.org/wiki/Chondrus_crispus#/media/File:Chondr... .
Other species, such as Lacuna vincta and Steromphala cineraria take advantage of pits made by P. pellucida to feed on the exposed, nutritious core of Laminaria stipes 25Pp flic.kr/p/YNN5QC .
Li et al. (2015) suggested that P. pellucida may have Batesian mimicry of nudibranchs with iridescence assumed to warn of repugnant secretions or stinging sequestered cnidocytes. But Batesian mimics are usually less numerous than their models as predators learn from the more numerous example and apply their learning to all. Iridescent nudibranchs are usually much less numerous than P. pellucida, so are unsuitable as models to mimic. Adults concealed in holdfasts have little need for camouflage or warning colouration, and are often coated with epizoic growths 92Pp flic.kr/p/ZmLoEm . The use of the rays for sexual attraction in a non-copulating species is unlikely, especially as the rays become much less obvious at maturity, and their primitive eyes, almost certainly, cannot distinguish the rays.
Breeds most months, with maximum in winter and spring; November to February in Plymouth. No copulation; female releases thousands of individual, planktonic ova with gelatinous coverings that swell on contact with water. Ova are fertilized by sperm shed into water by males. Eggs soon hatch into shell-less, rotating, planktonic trochophore larvae (stage passed within egg by most less “primitive” spp.)
Development: shell type numbers below refer to those in Part 1 - Shell Description.
After a few days, the trochophore larvae metamorphose into planktonic veligers with a weakly developed velum for swimming and food capture, and a slightly coiled shell (GS 1) 1Pp flic.kr/p/Z4FxDe .
After a short pelagic life, the veligers settle on the substrate and metamorphose into the juvenile limpet form (GS2) . Initially, they feed on small red weeds and can be found on rock surfaces 2Pp flic.kr/p/Z4FxAi . By the time they attain shell length 4mm the radula is strong enough to rasp Laminaria as well as scrape up diatoms and other microscopic organisms that have settled on the fronds 3Pp flic.kr/p/Z4FxtK . To reach the Laminaria, the animals secrete mucus to form a 'sail' many times the size of the shell. The sails bring the animals to near neutral buoyancy and catch any water movement so they readily lift off from the substrate. As 1m² substrate carrying a Laminaria bed has about 8 to 12m² of Laminaria surface (Vahl, 1983), there is a good chance that the sails will strike a Laminaria plant and stick to it, as the mucus is a strong instant underwater adhesive. (While manipulating a supine specimen in water for photography, the 0.5mm wide tip of my forceps struck the invisible mucus being exuded. When I lifted the forceps, the animal followed with a piece of adhering Laminaria four times its weight, and was detatched only with difficulty). Any that fail to contact Laminaria, or a sufficient substitute, will die; the scarcity of the species in very sheltered conditions may be because of the lack of water movement sufficient for lift off. The great majority of the survivors (juveniles GS3) take up residence on the frond where their position is maintained by negative geotaxy (Vahl,1983) and their orientation may be prow-like anterior towards on coming wave action or current 3Pp flic.kr/p/Z4FxtK , but the evidence for the cause of orientation is not clear as the movement of waves over waving fronds is difficult to ascertain. A few of the settling juveniles land on the stipe or get into a holdfast where they initially feed on a finger of the holdfast 6Pp flic.kr/p/Z4FqqB . All, regardless of where they live, have similar juvenile shells, except that those in holdfasts may start to develop a rougher surface 9Pp flic.kr/p/Yss7so . The extremely low profile of a smooth, juvenile shell on a frond or stipe, orientated with narrow anterior facing the current, has minimal drag 3Pp flic.kr/p/Z4FxtK , and the broad foot with strongly adhesive mucus has a very firm grip, so wave backwash up to 20m/s (c.70km/h) can be withstood at this stage (Denny, 1984, in Fretter & Graham, 1994). The low, streamlined shell profile is maintained by loss of shell material at the anterior as the posterior grows. The loss may be caused by physical wear, but as the substrate is plant surface it seems unlikely. Resorption locally by the anterior of the mantle is a possibility.
Sexual maturity is reached at shell lengths of about 5 mm and upwards (Graham & Fretter, 1947). A change from shell loss to growth at the anterior commences shortly after maturation, at shell length 7 or 8mm. By 10mm length there is a considerable band of new shell around the whole shell with encircling growth lines, parallel to the substrate, (early adult GS4) that have an angular unconformity where they meet the earlier tilted growth lines 15Pp flic.kr/p/YNKaz3. Blue lines are usually fewer, less distinct or absent on the new shell. The profile, viewed from the side, becomes a higher dome with a nick on the anterior profile where the convex early surface meets a nearly straight new surface 15Pp flic.kr/p/YNKaz3 . Drag in water currents becomes much greater than on the low profiles of GS3 shells, and most on the exposed frond are swept off before they reach 11mm length to die or, possibly, reach other Laminaria in deeper, calmer water with the aid of a mucus sail.
In very sheltered waters with small amounts of wave action, some on fronds survive to lengths of 14mm or 15mm and form impressive, smooth, high, conoid shells resembling a Phrygian cap (GS5) 20Pp flic.kr/p/Z4Y3uZ . But this form is relatively scarce, though easily seen when present, as the sheltered conditions required for its survival are not conducive to large populations of the species. On both sheltered shores and more exposed one, a few individuals find less turbulent conditions on the stipe 24Pp flic.kr/p/YsLJPW which has a much shorter arc of movement, diminishing to zero at its base, than the fronds that thrash back and forth in storms through a curve with about 2m diameter. The shell may resemble GS5, but if a wide pit is eaten into the stipe the newly deposited shell may flare out more widely so that the conoid has a lower profile with a break in slope at the junction of new and earlier shell 26Pp flic.kr/p/YMdFeA .
By far the largest number of those who survive into (GS5) are those who found their way into holdfasts at an early stage and have grown secure from wave impact, unless the plant is torn away. On parts of some shores, including exposed ones, about 50% of Laminaria holdfasts may be inhabited. Occupation is usually restricted to a single adult (GS4 or 5h) per holdfast . Occasionally, when several holdasts are intermingled, one pit make break through into another 94Pp flic.kr/p/ZmLn1u . For those on fronds, lifespan is about a year or less. Those in holdfasts may live for two or more years, if the plant survives. Occasional stranded specimens, perhaps from holdfasts cast up from deep calm water, have exceptionally large shells with growth rings suggesting an age of four years 25.1Pp flic.kr/p/YXMQGC .
The absence from Norway of P. pellucida living in holdfasts, and of the associated distorted shell form lacking blue rays on most of the adult growth, suggests a lack of genetic interchange between Britain and Norway. It appears that the short planktonic larval stage is insufficient to survive the time needed for it to drift from Britain to Norway.
Distribution and status
Iceland and Murman Coast (N. Russia) to Straits of Gibraltar. Not resident further into Baltic than Øresund, south-west Sweden or continental coast of North Sea apart from on occasional strandings of washed in Laminaria. GBIF map www.gbif.org/species/5728509
Frequent around Britain and Ireland on hard substrate where Laminaria is present. Both P. pellucida and Laminaria are absent or rare in Liverpool Bay and Flamborough Head to Kent apart from occasional individuals washed in from other areas. Often overlooked at times when only those hidden in holdfasts are present. U.K. distribution map NBN species.nbnatlas.org/species/NHMSYS0021056396
Acknowledgements
I (I.F.S) should like to thank Debbie Evans, Dr Marco Faasse, David Fenwick, Allan Rowat and Neil Ward for information and use of their images, and Dr Ivan Nekhaev and Dr Julia Sigwart for advice with the text and interpretation of the images. I am extremely grateful to my co-authors Erling Svensen and Paula Lightfoot for their invaluable contributions of images, information and constructive criticism. Any errors or omissions are my responsibility.
Links and references
Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 2 (1849), van Voorst, London. (As Acmaea virginea; Free PDF at archive.org/stream/historyofbritish02forb#page/428/mode/2up Use slide at base of page to select pp.429-433.)
Fretter, V. and Graham, A. 1962. British prosobranch molluscs. Ray Society, London.
Graham, A. 1988. Molluscs: prosobranch and pyramidellid gastropods: keys and notes for the identification of the species. Brill & Backhuys, for Linn. Soc. Lond. & Estuarine and Brackish-water Sciences Assoc. Synopses of the British Fauna (New Series) no.2. Edition 2 (662pages). Leiden. (Edition 1 of series, 1971, 112 pages, is no substitute.)
Graham, A. & Fretter, V. 1947. The life history of Patina pellucida (L.) J. mar. biol. Ass. U.K. 26: 590 to 601.
plymsea.ac.uk/1257/1/The_life_history_of_Patina_pellucida...
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.
Kain, J.M. & Svendsen, P.1969. A note on the behaviour of Patina pellucida in Britain and Norway. Sarsia, 38:1, 25-30. dx.doi.org/10.1080/00364827.1969.10411147
Lebour, M.V., 1937. The eggs and larvae of the British Prosobranchs with special reference to those living in the plankton. Journal of the Marine Biological Association of the United Kingdom, 22: 105 to166.
Li, L. et al. 2015. A highly conspicuous mineralized composite photonic architechture in the translucent shell of the blue-rayed limpet. Nat. commun. 6:6322 doi:10,1038/ncomms7322(2015). Free pdf (open access) at www.nature.com/articles/ncomms7322
and supplementary images and video at www.nature.com/articles/ncomms7322#supplementary-information
Wigham, G.D. & Graham, A. 2017. Marine gastropods 1: Patellogastropoda and Vetigastropoda. Synopses of the British Fauna (New Series) no.60. (172pages). Field Studies Council, Telford, England.
Yonge, C.M. and Thompson, T.E. 1976. Living marine molluscs. Collins, London.
Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=147459
GLOSSARY
afferent (adj. of vessel) = carrying blood etc. towards an organ.
aperture = mouth of gastropod shell; outlet for head and foot.
apex (definition for this account) = position of the larval protoconch (see summit).
branchial (adj.) = of or relating to gills (branchiae).
cephalic = (adj.) of or on the head.
cnidocytes = explosive stinging cells of hydroids, jellyfish, sea anemones etc. en.wikipedia.org/wiki/Cnidocyte
ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.
efferent (adj. of vessel) = carrying blood etc. away from an organ.
ELWS = extreme low water spring tide (usually near March and September equinoxes).
epizoic (of a plant or animal) = growing or living non-parasitically on the exterior of a living animal.
GS1, GS2 etc. = Growth Stage 1 (planktonic veliger larva), Growth Stage 2 (newly settled juvenile) etc.
GS5f = Growth Stage 5 (late adult) living on Laminaria frond.
GS5h = Growth Stage 5 (late adult) living in Laminaria holdfast.
GS5s= Growth Stage 5 (late adult) living on Laminaria stipe.
haemocoel = system of interconnected spaces (sinuses) containing blood within body of a mollusc.
holdfast = rootlike in appearance, but not in function, tendrils attaching seaweed to the substrate. (a.k.a. hapteron).
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).
osphradium (pl. osphradia) = organ for testing water quality (chemical and/or for particles) usually near approach of inhalant current to ctenidium or pallial gills. Structure varied; including comblike, papillate or ribbing.
pallial (adj.) = of, relating to, or produced by the mantle (pallium).
periostracum = thin horny layer of chitinous material often coating shells.
phylogenetic (of development) = of change due to genetic make up.
resorb = absorb again that which was previously produced.
resorption = the process of absorbing again that which was previously produced.
stipe = stem of some brown seaweeds that supports the fronds and may contain a core of cells that transports sugars and nutrients within the alga.
summit (definition for this account) = highest point of the shell above the substrate (see apex).
trochophore = spherical or pear-shaped larva that moves with aid of girdle of cilia that beat to cause rotation. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for patellid limpets, most Trochidae and Tricolia pullus, and, with no veliger, chitons.
veliger = shelled larva of marine gastropod or bivalve mollusc which feeds and swims by beating cilia of a velum (small on P. pellucida).
I ended up behind her in a crowd later and almost got clonked on the head by that hammer she has over her shoulder.
She was invited up to the front of the DC Nation panel.
At Comic-Con International ← Check out my write-ups.
One of the fun things about going in costume is you never know who's going to want to pose with you.
(photo taken by neil) (the ear protection is because someone was cutting wood just next to us, not because we were mixing silicone :)
I'm on the left; I spotted the guy on the right with a JSA group in line for the DC Nation panel.
I love the touch of including baby Hazel, and posing like the first cover.
Saturday at LA Comic Con 2016
Appropriately enough, I had to add some flash to this photo...
Friday at Comic-Con 2014. See also my write-up of the con.
Newly settled juveniles, less than 2 mm long on red, calcareous algae encrusting rock. Smooth, very shallow, pear-shape saucer. The apex at the anterior initially has a minute spiral protoconch (surviving larval shell) which is sealed off and lost soon after metamorphosis. The summit of the shell is further back. Aperture rim is on a single plane conforming to the flat surface of encrusting algae. Almost transparent, showing viscera. Two or three longitudinal rows of iridescent blue dashes.
Concise Key id. features: 1Pp flic.kr/p/Z4FxDe
Part 1, SHELL FORMS, BELOW
Part 2, BODY & ANATOMY: 3Pp flic.kr/p/Z4FxtK
Part, 3 HABITS & ECOLOGY: 4Pp flic.kr/p/Z4Fx9M
Sets of OTHER SPECIES: www.flickr.com/photos/56388191@N08/collections/
PDF available at www.researchgate.net/publication/346673416_Patella_pelluc...
Patella pellucida Linnaeus, 1758
Authors: Paula Lightfoot, Erling Svensen and Ian F. Smith (text) September 2017.
Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=147459
Synonyms: Anastes pellucida (Linnaeus, 1758); Helcion pellucidum (Linnaeus, 1758); Patella laevis Pennant, 1777; Patina pellucida (Linnaeus, 1758);
Vernacular names: Blue-rayed limpet, Peacock's feather (English); Brenigen lasresog, Brenigen rasen las (Welsh); Blåskæl (Danish); Blauwgestreepte schaalhoren (Dutch); durchscheinende Häubchenschnecke (German); Blåsnigel (Norwegian); Laminaria-skålsnäcka (Swedish); Helcion transparent (French);
GLOSSARY below.
Introduction
In addition to when they metamorphose from veliger larva to juvenile, all individuals of P. pellucida undergo pronounced morphological change when they mature at about 7mm length. Then, the anterior of the shell ceases to be reduced and starts to grow, probably because of a change from resorption to secretion by the mantle edge. Juvenile growth lines, shaped like tilted horseshoes open at the cut away anterior, are succeeded by unbroken growth lines around the entire shell, and the profile starts to rise. Subsequent adult survival and shell morphology vary greatly with the local environment and microhabitats used. The following describes the resulting forms in detail for the majority of individuals in Britain, but exceptions occur.
Shell Descriptions (Britain)
Growth stage1: veliger larva.
Habitat: Plankton. Shell length: Up to 0.2mm. Shape: initially a smooth bowl shape, rapidly becoming slightly spiral with barely more than one whorl (Lebour, 1937). 1Pp flic.kr/p/Z4FxDe Exterior surface: Smooth. Translucent.
Growth stage 2: newly settled juvenile.
Habitat: Usually on red, calcareous algae encrusting rock 2Pp flic.kr/p/Z4FxAi .
Shell length: Up to c. 2mm.
Shape: Very shallow saucer. The apex at the anterior intitially has a minute spiral protoconch (surviving larval shell) which is sealed off and lost soon after metamorphosis. The summit of the shell is further back. N.B. “apex” in this account refers to the protoconch location; the highest point of the shell above the substrate is referred to as the “summit”. Profile: Very low. Aperture outline: Pear-shape outline. Aperture rim: On a single plane conforming to the flat surface of encrusting algae. Exterior surface: Smooth, usually lacking epizoic growths. Translucence: Almost transparent, showing viscera. Colour: When live, the faintly horn-coloured shell is darkened by the visible viscera. Coloured rays: Two or three longitudinal rows of iridescent blue dashes .
Growth stage 3: juvenile.
Habitat: Laminaria fronds 3Pp flic.kr/p/Z4FxtK stipes 4Pp flic.kr/p/Z4Fx9M , and on 5Pp flic.kr/p/YNrZYJ and within 6Pp flic.kr/p/Z4FqqB holdfasts. Length: c. 2mm to c. 7mm. Height: Low, mean height 27% of length (Graham & Fretter,1947). Shape: Shallow saucer. Profile: Low, uninterrupted, streamlined 7Pp flic.kr/p/YLTpnd . Aperture outline: Oval, narrowest at anterior. Aperture rim: On a single plane conforming to the flat surface of Laminaria frond 8Pp flic.kr/p/Z4Fou2 . Those in holdfasts or depressions on stipes may have the rim curved up at the ends 9Pp flic.kr/p/Yss7so . Growth: Greatest at posterior, apex lost and anterior progressively removed, probably by resorption. Growth lines: horseshoe, open at anterior, in plan view. In side view, they slope downwards to where they end in the anterior quarter of shell. Most widely spaced at posterior 9Pp flic.kr/p/Yss7so . Thickness: very thin and fragile. Exterior surface: very smooth, no sculpture except fine growth lines 10Pp flic.kr/p/Z4FnSR , but less smooth with coarser growth lines if within a holdfast 9Pp flic.kr/p/Yss7so . Rarely, if ever, has any epibiotic growths. Translucence: almost transparent; body can usually be discerned through the shell 5Pp flic.kr/p/YNrZYJ . Colour: whitish, tinted horn to pale brown; partly due to the closely adhering, flimsy periostracum 8Pp flic.kr/p/Z4Fou2 . Coloured rays: two or three rows of iridescent blue/green hyphens/lines on 2mm and 3mm long shells 11Pp flic.kr/p/XQbnj8 ; about eight rows when 7mm long 12Pp flic.kr/p/YRn54i . Lines 0.1mm to 0.2mm wide. Occasionally, several red-brown rays among the blue ones 3Pp flic.kr/p/Z4FxtK . Interior: whitish, tinted horn to pale brown. Black, non-crystalline, colloidal particles underlie parts of the blue/green lines 13Pp flic.kr/p/YNKbDC . Sometimes, the horseshoe-shaped pedal retractor muscle-scar is visible14Pp flic.kr/p/XLDR8W .
Growth stage 4f, early adult on Laminaria frond.
Habitat: Laminaria fronds. Shell length: c. 7mm to c. 10mm. Height: raised, about 35% of length when 10mm long 15Pp flic.kr/p/YNKaz3 . Shape: dome. Profile: smoothly rounded, except for break in slope at anterior where new adult growth joins juvenile growth 15Pp flic.kr/p/YNKaz3 . Anterior steeper than posterior. Aperture outline: usually a broad oval 15Pp flic.kr/p/YNKaz3 , or almost circular 16Pp flic.kr/p/XLDNJ7 . Aperture rim: on a single plane conforming to the flat surface of Laminaria. Growth: growth commences at anterior. Adult growth forms a distinct skirt around the juvenile shell 15Pp flic.kr/p/YNKaz3 . Growth greater at posterior so the skirt is wider there. Growth lines: in plan view, now continuous around the whole shell on adult skirt. In side view, they slope down on the skirt towards the anterior, but are not cut off. Thickness: adult growth thicker and, sometimes, slight radial ribs develop on it. Exterior surface: very smooth, no sculpture except fine growth lines. Rarely has any epibiotic growths. Translucence: the brown, adult skirt is almost opaque 17Pp flic.kr/p/YNK8Wo , but the pedal-retractor muscle and, within the muscle outline, the blackish mantle and fine spray of black particles on the shell interior are discernible through the juvenile growth in good light 18Pp flic.kr/p/YNK81f . Colour: usually a stronger brown than on juveniles 18Pp flic.kr/p/YNK81f . Coloured rays: blue/green rays persist on juvenile growth, may extend onto new adult growth, but usually feeble 15Pp flic.kr/p/YNKaz3 or faint shadowy grey. Interior: juvenile area pale,translucent; adult skirt stronger brown. Increased number of black, colloidal particles under parts of the blue/green lines 19Pp flic.kr/p/Z4Y4Cv . Pedal retractor muscle-scar usually faint 16Pp flic.kr/p/XLDNJ7 .
Growth stage 5f, late adult on Laminaria frond.
Habitat: on Laminaria frond. Shell length: c. 11mm to c. 19mm.
Height: up to 50%, or more, of length. Shape: conoid, steeper at anterior, often resembles a Phrygian cap 20Pp flic.kr/p/Z4Y3uZ . Profile: posterior a long smooth convex curve, anterior a short and steep concave curve with break of slope where juvenile growth meets adult growth, and, on two year old individuals, where first year adult growth meets second year growth 21Pp .https://flic.kr/p/Z51JLg Aperture outline: a broad oval 22Pp flic.kr/p/Z51FP4 , sometimes approaching a circle 21Pp flic.kr/p/Z51JLg . Aperture rim: on a single plane conforming to the flat surface of Laminaria frond. Growth: wide skirt of adult growth all around shell makes up the majority of it. Posterior growth still exceeds anterior growth, but less markedly. Growth lines: in plan view, continuous around the whole shell on adult skirt. Thickness: increases only slightly. Exterior surface: smooth, usually with no epibiotic growth, or a little 20Pp flic.kr/p/Z4Y3uZ . Translucence: less than on juveniles, but can be sufficient for viscera to be discerned 22Pp flic.kr/p/Z51FP4 Colour: usually dark brown on live shells 21Pp flic.kr/p/Z51JLg . Coloured rays: blue lines persist on the juvenile growth and may continue on adult growth for part 21Pp flic.kr/p/Z51JLg or all 22Pp flic.kr/p/Z51FP4 of the way to the posterior edge, but often continuing as faint shadowy grey lines 21Pp flic.kr/p/Z51JLg . Rarely in Britain, bright blue lines continue on adult growth all around the shell 23Pp flic.kr/p/YRpuUg . Interior: variable colour, often blackish, with some iridescence 21Pp flic.kr/p/Z51JLg . Muscle scars vary in distinctness.
Growth stages 4s & 5s, adults on Laminaria stipe.
Habitat: Bowl-shape pit eaten into side of Laminaria stipe 24Pp flic.kr/p/YsLJPW & 25pp flic.kr/p/YNN5QC . Shell length: c.7mm to 10mm (4s) and c.11mm to 19mm (5s). Height: Variable, c.30% of length. Shape: Conoid, less steep than on frond dwellers because adult skirt flares laterally. Skirt forms majority of shell at stage 5 26pp flic.kr/p/YMdFeA . Profile: Posterior is two smooth convex curves with a very distinct break of slope between them. Anterior is convex on juvenile growth and straight on adult skirt, with a break of slope where the two parts meet. Aperture outline: A broad oval, sometimes approaching a circle. Aperture rim: Strongly curved up from the horizontal at the ends. Growth: Wide skirt of adult growth all around shell makes up the majority of it by stage 5. Posterior growth exceeds anterior growth.
Growth lines: In plan view, continuous around the whole shell on adult skirt. Thickness: Increased on both juvenile and adult growth by mantle secretion over the whole of the interior. Exterior surface: Smooth, often with no epibiotic growth, but some shells have small amounts, including algae 27Pp flic.kr/p/YRpsdK . Translucence: Adult growth opaque; juvenile growth may retain some translucence. Colour: Usually dark brown on live shells. Coloured rays: Blue lines persist on the juvenile growth and may continue on adult growth for part or all of the way to the posterior edge. Red-brown radiating lines are frequent, often alternating with the blue lines 26Pp flic.kr/p/YMdFeA . Interior: variable colour, often blackish or dark brown, with some iridescence. Muscle scars vary in distinctness; occasionally, there are a clearly marked, white mantle-attachment-scar, a distinct pedal-retractor-muscle scar and, within the muscle scar, a silky-white amphora mark 26Pp flic.kr/p/YMdFeA .
Growth stages 4h& 5h, adults within Laminaria holdfast.
Habitat: Bowl shaped cavity eaten into base of stipe within Laminaria holdfast 28Pp flic.kr/p/YRprJZ & 29Pp flic.kr/p/YsLEbY . Shell length: c.7mm to 10mm (4h) and c.11mm to 19mm, exceptionally 30mm (5h) 29.1Pp flic.kr/p/259hPe4 & 29.2Pp flic.kr/p/23McN7H .
Height: Mean height is 34% of length, varies17% to 57%. Shape: Wide variety of distorted conoids 30Pp flic.kr/p/YRpowg . Profile: very varied, but anterior steeper and shorter than posterior. Changes of gradient indicate change from juvenile to adult growth and, probably, annual pauses in growth. Aperture outline: a broad oval, sometimes approaching a circle 31Pp flic.kr/p/Z54JED . Aperture rim: Strongly curved up from the horizontal at the ends 28Pp flic.kr/p/YRprJZ & 32Pp flic.kr/p/YsPCqh . Growth: Wide skirt of adult growth all around shell makes up the majority of it by stage 5 33Pp flic.kr/p/Z54BWi . Posterior growth exceeds anterior growth. Growth lines: In plan view, lines are continuous around the whole shell on the adult skirt, but form tilted horseshoes on juvenile growth 34Pp flic.kr/p/YsPzTo . Thickness:Increased on both juvenile and adult growth by mantle secretion over the whole of the interior. Exterior surface: less smooth than on frond and stipe dwellers 35Pp flic.kr/p/YMgx9G and is very often partly 36Pp flic.kr/p/XQh5Kp or completely 37Pp flic.kr/p/XQh5nv coated with epizoic animals such as barnacles, bryozoa and tube worms. Smoother juvenile growth usually stays free of epizoa.
Translucence: Adult growth opaque 38Pp flic.kr/p/YMgFdh . Colour: Brown or dark brown.
Coloured rays: Blue lines persist on the juvenile growth, unless eroded 31Pp flic.kr/p/Z54JED and may, occasionally, continue on adult growth for part or all of the way to the posterior edge 35Pp flic.kr/p/YMgx9G but the blue is often less vibrant on the thicker adult growth. Red-brown radiating lines are frequent, often alternating with the blue lines 33Pp flic.kr/p/Z54BWi or replacing them 31Pp flic.kr/p/Z54JED & 39Pp flic.kr/p/Z54sFe . The lines are often concealed under epizoic growths. Interior: Varies, often partly iridescent 37Pp flic.kr/p/XQh5nv . Often the peripheral zone is brown, and the area within the pedal-retractor-muscle scar is grey or blackish 39Pp flic.kr/p/Z54sFe . The distinctness of the p-r-m scar, and of the mantle-attachment scar, varies from very clearly defined 36Pp flic.kr/p/XQh5Kp to indiscernible 35Pp flic.kr/p/YMgx9G . Usually, from the interior, any exterior blue lines hidden but, occasionally, they are faintly visible 33Pp flic.kr/p/Z54BWi .
Stranded shells
The layer of zig-zag lamellae of calcite that iridesces the blue rays is close to the surface and often abraded from beachworn shells, which consequently often lack rays 40Pp flic.kr/p/YNQK3W Occasionally the rays are eroded while live 31Pp flic.kr/p/Z54JED .
Shell Descriptions (Norway)
The following is based mainly on information and images from the Egersund area in southern Norway, and on Kain & Svendsen (1969). Images from other areas of Norway might require revision of this account. There are several differences in appearance and behaviour from those in Britain.
No images are available of newly settled juveniles under 2mm length (Growth Stage 2) on encrusting red calcareous algae (usual habitat in Britain), but an early adult (GS4) was photographed on calcareous algae 41Pp flic.kr/p/XAavbr . Juveniles (GS3) were observed on sublittoral fronds of Laminaria hyperborea 42Pp flic.kr/p/YQa8Xp and L. saccharina 43Pp flic.kr/p/YdW7zA . They had nearly-transparent, blue-rayed, low, smooth, streamlined shells, cut way at the anterior, similar to British examples. Early adults (GS4), as in Britain, cease anterior shell-loss and commence thicker growth all around the perimeter, and the anterior rises to form a dome 44Pp flic.kr/p/YdW49C . But, there is a marked difference from Britain because the new adult growth usually has blue rays, as vivid as on the juvenile, now on the anterior as well as the posterior 45Pp flic.kr/p/YyPJ7y . Those that survive as later-adults (GS5f) on fronds continue to have blue rays all around the shell as it grows 46Pp flic.kr/p/YBsbVD , and a few gain sufficient height to approximate to a Phrygian cap in profile 47Pp flic.kr/p/YBsanD & 48Pp flic.kr/p/Xy66BJ . A minority live on stipes 49Pp flic.kr/p/YyPF9u almost always on the top 10cm, including the junction of stipe with frond 50Pp flic.kr/p/XAamFR . Photographs viewed showed juveniles (GS3) and early adults (GS4) in pits that sometimes coalesce 51Pp flic.kr/p/YBs7iH . The shell-forms on stipes (GS3s & 4s) were similar to those on fronds, but they differed by usually lacking any, or many, blue rays on the anterior 52Pp flic.kr/p/XAajp6 and so resembled British specimens. Not a single distorted holdfast-dweller (GS5h), nor a vacant P. pellucida pit in a holdfast, was discovered in large samples from exposed and sheltered sites in Espegrend, S.W. Norway and Tromsö, N. Norway, and it appears that this form is absent from Norway (Kain & Svendsen,1969) .
GLOSSARY
afferent (adj. of vessel) = carrying blood etc. towards an organ.
aperture = mouth of gastropod shell; outlet for head and foot.
apex (definition for this account) = position of the larval protoconch (see summit).
branchial (adj.) = of or relating to gills (branchiae).
cephalic = (adj.) of or on the head.
cnidocytes = explosive stinging cells of hydroids, jellyfish, sea anemones etc. en.wikipedia.org/wiki/Cnidocyte
ctenidium = comb-like molluscan gill; usually an axis with a row of filaments either side.
efferent (adj. of vessel) = carrying blood etc. away from an organ.
ELWS = extreme low water spring tide (usually near March and September equinoxes).
epizoic (of a plant or animal) = growing or living non-parasitically on the exterior of a living animal.
GS1, GS2 etc. = Growth Stage 1 (planktonic veliger larva), Growth Stage 2 (newly settled juvenile) etc.
GS5f = Growth Stage 5 (late adult) living on Laminaria frond.
GS5h = Growth Stage 5 (late adult) living in Laminaria holdfast.
GS5s= Growth Stage 5 (late adult) living on Laminaria stipe.
haemocoel = system of interconnected spaces (sinuses) containing blood within body of a mollusc.
holdfast = rootlike in appearance, but not in function, tendrils attaching seaweed to the substrate. (a.k.a. hapteron).
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).
osphradium (pl. osphradia) = organ for testing water quality (chemical and/or for particles) usually near approach of inhalant current to ctenidium or pallial gills. Structure varied; including comblike, papillate or ribbing.
pallial (adj.) = of, relating to, or produced by the mantle (pallium).
periostracum = thin horny layer of chitinous material often coating shells.
phylogenetic (of development) = of change due to genetic make up.
resorb = absorb again that which was previously produced.
resorption = the process of absorbing again that which was previously produced.
stipe = stem of some brown seaweeds that supports the fronds and may contain a core of cells that transports sugars and nutrients within the alga.
summit (definition for this account) = highest point of the shell above the substrate (see apex).
trochophore = spherical or pear-shaped larva that moves with aid of girdle of cilia that beat to cause rotation. Stage preceding veliger, passed within gastropod egg in most spp. but free in plankton for patellid limpets, most Trochidae and Tricolia pullus, and, with no veliger, chitons.
veliger = shelled larva of marine gastropod or bivalve mollusc which feeds and swims by beating cilia of a velum (small on P. pellucida).
Reverse Flash is looking over at my 6YO son who's about to photobomb the frame in about two seconds.
@findnjewels as Jesse Quick
@new_element_studios as Kid Flash
@vigilantecosplay as Reverse Flash
Saturday at WonderCon 2017 (writeup)
Green Lantern, Spider-Man, and, um, someone (looks like Anna Mercury, don't think that's right) join X-Men Cyclops, Wolverine and Nightcrawler.
Waiting in the space between Marvel's Dark Reign panel and the DC Universe panel.
Laminaria hyperborea kelp forest
Date: 04/08/2015
Location: Loch Eriboll
Geographic position: 58°33'23" N 4°36'9" W
Original image file size: 27.8MB (.NEF - RAW format)
Photographer: George Stoyle
© SNH. All rights reserved. Please email for details - marinephotos@nature.scot
Fonte official FB page:
www.facebook.com/arkonarussia/info
The roots of Arkona are to be searched for in the beginning of 2002, when the members of local pagan community "Vyatichi" – Maria "Scream" Arhipova and Alexander "Warlock" Korolyov decided to form a band, according to their ideology and musical tastes.
Initially, the band was called "Hyperborea", it consisted of: Maria "Scream" Arhipova (vocal), Eugene Knyazev (guitar), Eugene Borzov (bass-guitar), Ilya Bogatyryov (guitar), Alexander "Warlock" Korolyov (drums), Olga Loginova (keyboard). In February 2002 the band was renamed into "Arkona". The musical materials of the band were pagan/folk metal based and the lyrics had an idea of ancient national beliefs and history of Slavonic Russia .
In the end of the year it was decided to record several songs as a demo-record. The process of recording took place in December 2002, at CDM-Records studio. The demo consisted of 3 tracks – "Kolyada", "Solntsevorot" and "Rus'"Now this record is included into live-play album "Zhizn' vo slavu" (2006) as bonus material.
Since the beginning of 2003 the band has started its concert activity. Many people heard them for the first time at "Yazycheskaya Rus'" fest, which was held 8th February 2003 at "Estakada" club. Other bands that took part there were Butterfly Temple , Pagan Reign, Svarga, Rossomahaar.
Until summer 2003 the band performed a few local concerts, and then the question of debut LP recording was raised.
Unfortunately, by that time, several band members had lost interest for the further musical creativity, and in September 2003 the band Arkona dissapears.
Maria decided to keep on solo and asks her Nargathrond project mates for help in recording an opening LP. She got all the orchestration written down and musicians obtained them for learning and training. By March 2004 the first LP "Vozrozhdenie" was recorded without even a single rehearsal.
Nowadays this LP is spread all over the world and has received its recognition. It is recognized as one of the most successful Slavonic pagan metal LP ever. Immediately after studio work, Maria dedicates herself to the creation of new songs, and by the end of summer 2004 the material for the second album "Lepta" was ready. It was recorded the following autumn with the same musicians.
The album was released in December 2004 and, though LP continues the same old themes from "Vozrozhdenie", it is done in more dark and gloomy style. In the recording of this LP (as in the recording of previous one) took part a poet and vocalist Les’yar ( Nevid', ex-Butterfly Temple ), not only as a performer, but also as lyrics writer (the song "Zarnitsy Nashei Svobody").
By the moment of LP release, Arkona revived as a band - it consisted of musicians, which took part in recording of two first LPs. They were: Sergey "Lazar" (guitar), Ruslan "Knyaz'" (bass-guitar), Vlad "Artist" (drums). Since the beginning of the year 2005 the band could be seen again performing live.
Irrepressible creativity of Maria doesn’t let her stop and by summer 2005 the band starts recording the third LP, the most complicated and varied album "Vo Slavu Velikim". The band decided to give up on using any synthesized instruments and used real ethnic instruments, so the list of musicians, that took part in this recording, considerably extended. One of the invited was a famous folk-musician Vladimir Cherepovskiy (Mervent, ex- Voinstvo Sidov, Veter Vody, Trio Mario) and members of bands Svarga and Alkonost.
The orchestration for the songs sometimes included over 100 record tracks, but the band overcame these difficulties and in September 2005 the LP gone gold. During its presentation the live performance was recorded and was released as a DVD and also included into live LP "Zhizn’ vo Slavu".
In May 2007 Arkona started recording the 4th album 'Ot Serdca K Nebu' ('From Heart to the Skies'), where the previously started theme of the rebirth of culture and native Slavic religion found its continuation.
As for the music of this album, it represents the mix of modern metal styles: from brutal death metal ('Shrouds of Celestial Sage') and raw black metal ('Over the Abyss of Ages') up to beautiful ballad rock ('Oh, My Sorrow, My Anguish') and lofty epic metal ('Long live Rus!', 'Kolo Rolls'), and also somber doom ('The Arrow').
All the variety is saturated with the atmosphere, characteristic for all works by Arkona, and plenty of Slavic folk... As it was on the previous record, all parts of ethnic wind instruments were composed by a very special musician, a specialist in ancient music, Vladimir Cherepovsky (gaita, gallega, small pipe, hurdy-gurdy, tin whistle, low whistle, sopilka, pipes, pan flute, ocarina, zafun).
Also the vocalists of the Byelorussian folk choir 'Gostitsa' took part in recording.
The design of the album cover was developed by the famous Belgian artist Kris Verwimp...
The March of 2008 was a turning point for the band. Arkona performed as one of the headliners at the biggest European pagan metal fest called Ragnarok Festival V. The performance was eagerly supported by more than 5000 pagan metal fans from every part of the world.
When they got home, there was a nice surprise waiting for them: a proposition to sign a contract with one of the biggest European labels Napalm Records, concerning the release of the album 'Ot Serdca K Nebu' and future works of the band.
After Napalm Records released it, the band went on a 30-day tour in Europe, which ended with the performance at the great festival called BRUTAL ASSAULT.
Back at home the band decided not to go on a long hiatus and in October 2008 started working on their 5th album 'Goi, Rode, Goi.'
The level maintained on the album 'Ot Serdca K Nebu' was very high, but the band aimed to make a very unique album, something that had never been done before by them.
In the breaks during recording the band managed to release and present the second DVD "Noch Velesova" in May 2009 at Napalm Records, and also Arkona performed at the German festival 'Winternoise.'
The work on the album was finished only in June 2009, and we can say now that it was the most laborious and time-taking recording, where more than 40 musicians participated.
For the first time the band used a full-fledged chorus and a string quintet, and the special pearl of this album is the 15-minute saga 'Na Moey Zemle' which is about the adventures of a Slav in European countries, with the participation of the musicians from such bands as Manegarm, Obtest, Skyforger, Menhir and Heidevolk.
The parts of ethnical instruments on this album are performed partly by Vladimir Cherepovsky and partly by Vladimir 'Volk', who has become a full-blown member of Arkona recently.
The album cover design was done by Kris Verwimp, known to many. He carried out enormous work drawing a series of conceptual illustrations for each song of this album.