Anadara corbuloides
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Anadara corbuloides |
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| ( Monterosato , 1878) |
Anadara corbuloides is a shell - type from the family of ark shells (Arcidae) in the order of Arcida . It occurs in the eastern Atlantic and Mediterranean.
features
The slightly unevenly hinged, relatively large case is heavily expanded. It is spherical-egg-shaped in outline and is up to 7 cm long, but mostly it only reaches 5 cm in length. The flap on the left is slightly larger than the flap on the right, and is particularly noticeable on smaller specimens. This inequality disappears with large specimens. The length / height / thickness ratio is about 10: 8: 8 to 10: 7: 7 for large specimens. It is strongly unequal, shortened at the front and lengthened to the rear. The dorsal margin is straight and forms clear angles with the front and rear ends. The angle towards the front end is steep, that towards the rear end is relatively flat. The front edge is flat arched, almost straight to very, very slightly concave, the rear edge is more clearly arched. The ventral margin is well arched. The case doesn't gap all the time. The large, broad vertebrae lie in the front half (at about 30% of the front end) and are curled forward. But they are far apart. The ligament is very large and takes up a large part of the entire area. It is egg-shaped, the rear, narrow end slightly pointed, or flat-elliptical with pointed ends. Overall, the area is slightly concave.
The lock plate is long and comparatively narrow; however, the width decreases significantly towards the middle. As a result, the lower edge is slightly concave. The lock is taxodontic , the teeth become stronger towards the front and rear ends and diverge slightly outwards, e.g. Sometimes they are also a bit angular. The outer teeth are often bumpy, somewhat more irregular. In the front part there are up to 37 teeth, in the rear part up to 39 teeth. The outer edge of the lock is delimited by a distinct furrow at the front and back.
The yellowish-whitish shell is thick and the housing is correspondingly heavy. It is colored more intensely towards the vertebrae. The ornamentation consists of 30 to 35 clearly pronounced, radial-rayed ribs, which are flattened at the top and are about as wide as the spaces in between. The ribs are slightly curved towards the rear end. They weaken significantly towards the front end, less clearly towards the rear end. The ribs cross with growth lines; this gives the surface a rough appearance. The ribs are slightly serrated at the edges towards the outer edge of the case, and slightly granular towards the vertebrae. The organic periostracum is reddish to brownish, but flakes off easily. It is usually only preserved in the spaces between the ribs. There it is drawn out into bristles, the bristles point in the direction of the vertebra. The inner edge is strongly serrated.
There are two distinct sphincter scars that are only slightly dissimilar in size; the posterior sphincter is slightly larger.
Geographical distribution and habitat
The distribution area of the species extends in the eastern Atlantic from southern Portugal to northern Angola ; it also occurs in the Mediterranean .
The depth distribution ranges from shallow subtidal to about 100 meters water depth. The animals live buried in muddy to muddy-fine sandy soils and feed on microorganisms by filtering.
Taxonomy
In 1875 Tommaso di Maria Allery Monterosato described an Arca polii var. Grandis from the Mediterranean. In 1878 he raised the variety to species rank and renamed the taxon Arca corbuloides . Arca grandis would have been preoccupied by Arca grandis Broderip & Sowerby in 1829. The species is generally recognized and is placed in the genus Anadara Gray, 1857.
Commercial importance
The species is only occasionally taken as bycatch in dredges , trawls and ground nets, particularly in the Mediterranean and Black Seas.
literature
- P. Graham Oliver, Rudo von Cosel: Taxonomy of Tropical West African Bivalves. IV. Arcidae. Bulletin du Muséum national d'Histoire naturelle du Paris, 4th series, secion, 14A (2): 293–381, Paris 1992 PDF , here pp. 353–356.
Web links
Individual evidence
- ↑ a b Wilhelm Kobelt: The genus Arca L. In illustrations according to nature with descriptions. Systematic Conchylia Cabinet by Martini and Chemnitz, 8 (2): 1-238, Nuremberg 1891 Online at www.biodiversitylibrary.org (p. 82/83), plate 43 .
- ^ Tommaso Allery di Monterosato: Nota sopra alcune conchiglie coralligene del Mediterraneo. Bullettino della Società malacologica italiana, 6: 243-259, Pisa 1881 Biodiversity Heritage Library , pp. 246/47.
- ^ Tommaso Allery di Monterosato: Nuova Rivista delle Conchiglie Mediterranee. Atti della Accademia di scienze, lettere e arti di Palermo, 5: 1-50, Palermo, 1875, here p. 12.
- ^ Tommaso Allery di Monterosato: Enumerazione e sinonimia delle conchiglie Mediterranee. Atti della Accademia di scienze, lettere e arti di Palermo 55 p., Palermo, 1878 snippets on Google
- ↑ MolluscaBase: Anadara corbuloides (Monterosato, 1881) (here, however, with the wrong date)
- ^ Kent Carpenter, Nicoletta De Angelis: The Living Marine Resources of the Eastern Central Atlantic. Volume 2 Bivalves, gastropods, hagfishes, sharks, batoid fishes, and chimaeras. Food and Agriculture Organization of the United Nations, Rome, 2016 (FAO Species Identification Guide for Fishery Purposes) PDF , p. 696.
- ↑ Ramasamy Santhanam: Biology and Ecology of Edible Marine Bivalve Molluscs. Apple Academic Press, Waretown, New Jersey 2018 ISBN 978-1-77188-626-0 Preview at Google Books , p. 173.