Bathyarca glacialis

Bathyarca glacialis
	Bathyarca glacialis (from Kobelt, 1891: Pl. 38, Fig. 5 + 6)
Systematics
Order :	Arcida
Superfamily :	Arcoidea
Family :	Ark clams (Arcidae)
Subfamily :	Bathyarcinae
Genre :	Bathyarca
Type :	Bathyarca glacialis
Scientific name
	Bathyarca glacialis
	( Gray , 1824)

Bathyarca glacialis is a mussel species from the family of ark mussels (Arcidae) in the order Arcida .

features

The mostly equilateral, more rarely also slightly unevenly folded, slightly inflated case has a rounded, oblong-trapezoidal outline. The left flap is slightly larger than the right flap, which sits in the left flap. The housing is up to 30 millimeters long (in the north of the distribution area) and is longer than it is high (L / B index = 1.6), the rear part of the housing is slightly longer. In the southern part of the distribution area, the housing remains significantly smaller at around 15 millimeters. The strong vertebrae sit at a third of the total dorsal length from the anterior end. The dorsal margin is long and straight. The dorsal field is comparatively narrow and even rises slightly towards the hinge of the two valves. The rear edge is broadly rounded, the front edge is slightly curved. The transitions from the anterior dorsal margin to the anterior margin and also to the ventral margin are broadly rounded. The transition from the posterior dorsal margin to the posterior margin is very flat angled. The rear edge is only slightly convex; the transition to the ventral margin is tightly rounded to slightly angled. The ventral margin is moderately deeply rounded. In the ventral margin there is a recess for the byssus ; ie even when the housing is closed, the two flaps gape here. A flat sine in the middle of the housing (viewed in the longitudinal direction) is only present in smaller housings. The inner edge of the left, larger flap shows weak serrations, the inner edge of the right smaller flap is smooth.

The lock is taxodont , the lock plate is slightly curved. The teeth are in two groups, which are interrupted by a toothless area in the middle of the lock plate. In the front group there are up to ten teeth (usually fewer), the rear group contains 10 to 14 teeth. The back teeth are longer and more tilted than the teeth in the front group. The diamond-shaped ligament lies behind the vertebrae and consists of a few angles.

The whitish skin is thin, but still not fragile. The populations in the south of the distribution area have somewhat thicker shells. The ornamentation consists of numerous, radial, fine and dense ribs, which are interrupted by growth stops. The periostracum is thin, brown in color and drawn out into hairs.

The two sphincters are of different sizes; the anterior sphincter is only about two thirds the size of the posterior sphincter.

Geographical distribution, way of life and habitat

The distribution area of Bathyarca glacialis extends from the Arctic on both sides of the Atlantic to the Gulf of St. Lawrence and the Mediterranean Sea . While the species in the Arctic lives more in coastal areas and shallower water, it occurs in the southern areas of the distribution area on the continental slope, rarely also in bathyal areas. The depth range is specified from about six meters to 4,170 meters of water. Bathyarca glacialis lives attached to the byssus on muddy, more rarely also stony soils.

Taxonomy

The taxon was proposed by John Edward Gray in 1824 as Arca glacialis . The species is now generally assigned to the genus Bathyarca Kobelt, 1891.

supporting documents

literature

Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. 256 p., Gustav Fischer Verlag, Stuttgart 1969 (p. 22)
Graham Oliver, JA Allen: The Functional and Adaptive Morphology of the Deep-Sea Species of the Arcacea (Mollusca: Bivalvia) from the Atlantic. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 291 (1045): 45-76, 1980, JSTOR 2395365

On-line

Marine Bivalve Shells of the British Isles: Bathyarca glacialis (JE Gray, 1824) (site of the National Museum Wales, Department of Natural Sciences, Cardiff)

Individual evidence

^ Wilhelm Kobelt: The genus Arca L. In illustrations after nature with descriptions. Systematic Conchylia Cabinet by Martini and Chemnitz. Volume 8, Section 2, 238 pp., Bauer & Raspe, Nuremberg, 1891 Online at www.biodiversitylibrary.org (p.150) or plate 38
↑ John Edward Gray: Shells. In: Parry WE (Ed.): Supplement to Appendix, Parry's Voyage for the Discovery of a north-west passage in the years 1819-1820, containing an account of the subjects of Natural History. London: John Murray Appendix 10, Zool .: 240-246, 1824 Online at www.biodiversitylibrary.org (S.CCXLIV = 244)
↑ World Register of Marine Species: Bathyarca glacialis (Gray, 1824)

Web links

Commons : Bathyarca glacialis - collection of images, videos and audio files

[Kobelt1891-1] Wilhelm Kobelt: The genus Arca L. In illustrations after nature with descriptions. Systematic Conchylia Cabinet by Martini and Chemnitz. Volume 8, Section 2, 238 pp., Bauer & Raspe, Nuremberg, 1891 Online at www.biodiversitylibrary.org (p.150) or plate 38

[Gray1824-2] John Edward Gray: Shells. In: Parry WE (Ed.): Supplement to Appendix, Parry's Voyage for the Discovery of a north-west passage in the years 1819-1820, containing an account of the subjects of Natural History. London: John Murray Appendix 10, Zool .: 240-246, 1824 Online at www.biodiversitylibrary.org (S.CCXLIV = 244)

[Worms-3] World Register of Marine Species: Bathyarca glacialis (Gray, 1824)