Bentharca asperula

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Bentharca asperula
Systematics
Order : Arcida
Superfamily : Arcoidea
Family : Ark clams (Arcidae)
Subfamily : Bathyarcinae
Genre : Bentharca
Type : Bentharca asperula
Scientific name
Bentharca asperula
( Dall , 1881)

Bentharca asperula is a mussel species from the family of ark mussels (Arcidae).

features

The housing, which has the same flaps, is roughly elongated rhombic to wedge-shaped. The maximum length is 10 millimeters. It is significantly longer than it is tall (L / B index = 1.6), and comparatively slim and not bulky (L / D index 3.2). The rear part of the housing is strongly drawn out, the vertebra is located about a quarter of the total dorsal length from the front end. The vertebrae are low and protrude above the almost straight, very long dorsal margin. At the anterior end, the dorsal edge merges into the anterior edge at an almost rectangular angle. At the posterior end, the transition from the dorsal margin to the posterior margin is bluntly angled. The rear edge then initially falls straight or even slightly concave. The rear end is angled or tightly rounded. The transition to the actual ventral edge can also be slightly butted angled. The ventral margin is very slightly arched or even slightly concave. The front edge is slightly rounded, slopes very gently and merges into the curve of the ventral edge without breaking. The indentation of the byssus is clearly visible in the ventral margin ; here the two flaps gape even when the housing is closed. The back, which is initially attached to the vertebra at the angle between the posterior and ventral margins, quickly flattens out and is no longer noticeable halfway to the posterior margin. The rear end is broadly rounded, the front end angled. In the midfield, a flat sinus emanating from the vertebra runs to the ventral edge of the housing. The dorsal field is narrow and flat. The inner edge of the case is smooth.

The lock edge is straight, the lock is taxodont . The ligament first extends over the posterior dorsal margin, and later also between the vertebrae. The teeth of the lock are very small and sit in two groups separated by a toothless part of the lock plate on a narrow plate. There are five teeth in the front group and six in the back. The front teeth are inclined to the lock plate, the rear teeth are arranged approximately parallel to the dorsal edge.

The skin is thin but not translucent. The ornamentation consists of concentric, widely spaced low ribs, which are interrupted by radial rows of bristles. The periostracum is drawn out to dark brown bristles on the rear housing field, it is curled on the middle field and the front housing field. The shell itself is whitish.

The two sphincters are unequal in size; the anterior sphincter is smaller than the posterior sphincter.

Geographical distribution and habitat

The range of the species extends over almost all oceans with the exception of the Arctic and Antarctic . They live there at a depth of between 430 and 5000 meters. In the eastern Atlantic they were z. B. also detected in the deeper areas of the Biscay and the Rockall Trough .

The animals attach themselves to small stones and other hard substrates, including the shells of Limopsis tenella , with thin byssus threads .

Taxonomy

The first description of this species was published by William Healey Dall in 1881 as Macrodon asperula . The taxon is the type species of the genus Bentharca Verrill & Bush, 1898. Synonyms of Bentharca asperula (Dall, 1881) are: Arca culebrensis EA Smith, 1885, Arca endemica Dall, 1908, Arca paserula Sheldon, 1916, Arca profundicola Verrill & Smith in Verrill, 1885 and Arca pteroessa EA Smith, 1885.

supporting documents

literature

  • Markus Huber: Compendium of Bivalves. 901 S., Hackenheim, ConchBooks, 2010 ISBN 978-3-939767-28-2
  • 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. 23 as Bentharca pteroessa and Bentharca culebrensis )

On-line

Individual evidence

  1. ↑ Flávio Dias Passos, Adolpho Birman: New records of Bentharca asperula (Dall, 1881) (Mollusca, Bivalvia, Arcidae) from Brazil. Biota Neotropica, 9 (4): 281-283, 2010 PDF .
  2. ^ William Healey Dall: Report on the Results of Dredging by the United States Coast Survey Steamer "Blake" XV. Preliminary Report on the Mollusca. Bulletin of the Museum of Comparative Zoology at Harvard College, 9: 33-144, Harvard Online at www.biodiversitylibrary.org (p. 120).
  3. ^ World Register of Marine Species: Bentharca asperula (Dall, 1881) .

Web links