Mussel shell
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![Basket clam (Varicorbula gibba) (from GB Soberby, 1859: Plate 1, Fig. 22 [1])](https://de.wikipedia.org/wiki/Datei:GBSowerbyII1859_pl1_fig22_Corbula_gibba.png)
Basket clam ( Varicorbula gibba ) (from GB Soberby, 1859: Plate 1, Fig. 22) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Varicorbula gibba | ||||||||||||
| ( Olivi , 1792) |
The basket mussel ( Varicorbula gibba ) is a type of mussel from the family of the basket mussels (Corbulidae) in the order of the Myida .
features
The unevenly hinged, heavily expanded housing is up to 15 mm long. The right flap is significantly larger and more arched than the left flap; the left flap sits in the right flap. The case is also unequal, with the vertebrae sitting well in front of the center line. The outline of adult cases is rounded-triangular. The front edge is broadly rounded, the rear edge is somewhat elongated and trimmed. Juvenile housings are broadly ovoid. The rear edge is not that much elongated. The posterior and anterior dorsal margin are slightly concave and steeply sloping, the ventral margin is broadly rounded.
The ligament rests internally on a protruding chondrophore in the left valve. There is only one corresponding recess in the right flap. The right valve has a strong main tooth, in the left valve there is a pit corresponding to the tooth of the right valve next to the chondrophor. In the right flap, posterior teeth are indicated from the front and rear. There are two sphincters. The posterior sphincter is rounded, the anterior crescent-shaped. The surface line is entire, but truncated or only very slightly inflected in the area of the siphons.
The shell is firm. The outer edge areas of the left valve (approx. 10%) are not mineralized, but consist only of thick periostracum. The color is very variable: from white to cream and yellow to purple. The ornamentation on the right flap consists of ribs that are parallel to the edge and rounded on the top at regular intervals. Irregularities occur in areas with growth interruptions. On the left flap the ribs are a little finer and there are still some fine radial lines in the middle. The inner edge of the case is smooth. The periostracum is thick, fibrous and rusty brown in color. It is mostly only preserved on the left flap. The siphons are very short. The foot is long and thin.
Geographical distribution and habitat
The distribution area extends in the East Atlantic from Norway to West Africa and Angola . It also penetrates into the tributaries of the North Sea , Baltic Sea , Mediterranean and Black Sea .
The mussel lives buried shallow in muddy-silty, muddy-sandy or even muddy-gravelly sediments. The rear end just reaches the sediment surface. It is attached to fragments of shell or stones in the sediment with a byssus thread . It seems to rarely change its position and is an almost sessile suspension filter that feeds on diatoms , bacteria and organic detritus in the immediate vicinity of the sediment surface.
It occurs from the deeper tidal range up to about 250 meters water depth, in the literature up to 2,000 m are also given. In the North Sea it can be found up to 50 meters water depth, in the Baltic Sea from 7 to 31 meters water depth. In habitats suitable for the species they occur very frequently, often even in large numbers.
Taxonomy
The taxon was founded in 1792 by Giuseppe Olivi in the original combination Tellina gibba . It is the type species of the genus Varicorbula Grant & Gale, 1931, which, however, is considered by some authors as a synonym of Corbula Bruguière, 1797 or as a subgenus of Corbula . MolluscaBase accepts Varicorbula as a valid genus, but, contrary to the international rules of zoological nomenclature , places the mussel in the genus Corbula . MolluscaBase lists the following synonyms for Variocorbula gibba on: Corbula curta Locard, 1886, Corbula gibba var. Albida Bucquoy, Dautzenberg & Dollfus, 1896, Corbula gibba var. Fusca Bucquoy, Dautzenberg & Dollfus, 1896, Corbula gibba var. Maxima Bucquoy, Dautzenberg & Dollfus, 1896, Corbula gibba var. radiata Bucquoy, Dautzenberg & Dollfus, 1896, Corbula haastiana Hutton, 1878, Corbula mactriformis Biondi Giunti, 1859, Corbula nucleus Lamarck, 1818, Corbula ovata Forbes, 1838 Corbula rosea Brown, 1844 Corbula striata Fleming, 1828, Mya inaequivalvis Montagu, 1803, Tellina naticuta Brusina, 1870 and Tellina olimpica OG Costa, 1830.
In the molecular biological analysis of the Corbulidae by Hallan et al. (2013) three clades emerged: the LEC (limnetic-euryhaline Corbulidae), the Caribbean group (Caribbean) and a western Pacific group (Western pacific). Amazingly, Varicorbula gibba belonged to the West Pacific group.
supporting documents
literature
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 82)
- 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. 149)
- Guido Poppe, Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint) ISBN 3925919104 (p. 129)
- Rainer Willmann: Mussels of the North and Baltic Seas. 310 pp., Neumann-Neudamm, Melsungen 1989 ISBN 3-7888-0555-2 (pp. 180–181)
- Charles Maurice Yonge : On the habits and adaptations of Aloidis (Corbula) gibba. Journal of the Marine Biological Association of the United Kingdom, 26: 258-276, Plymouth, 1946 PDF
On-line
Individual evidence
- ↑ George Brettingham Sowerby II : Illustrated index of British shells. containing figures of all the recent species, with names and other information. XV S., XXIV plate, London, Simpkin, Marshall & Co., 1859 Online at www.biodiversitylibrary.org (plate 1)
- ^ Giuseppe Olivi: Zoologia Adriatica, ossia catalogo ragionato degli animali del golfo e della lagune di Venezia Bassano , Venecia. 334pp, 1792 Online at www.biodiversitylibrary.org (p. 101).
- ↑ a b MolluscaBase: Corbula gibba (Olivi, 1792)
- ↑ Anders Hallan, Donald J. Colgan, Laurie C. Anderson, Adriana García, Allan R. Chivas: A single origin for the limnetic-euryhaline taxa in the Corbulidae (Bivalvia). Zoologica Scripta, 42: 278-287, 2013 doi : 10.1111 / zsc.12010 .