Pocket knife clam
| Pocket knife clam | ||||||||||||
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Pharus legumes |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Pharus legumes | ||||||||||||
| ( Linnaeus , 1758) |
The pocket knife clam ( Pharus legumen ) is a mussel from the family of Pharidae .
features
The very flat housing, which has the same flaps, is "ensiform", ie the dorsal edge and the ventral are almost parallel. It grows to 13 cm long at a height of about 2.5 cm. This results in a width to height ratio of about 5. The shells are almost equilateral, the low and little protruding vertebrae lie in the center line or slightly shifted towards the front end. The case is slightly higher at the rear end than at the front end. In addition, the rear end is trimmed almost vertically, the front end tightly rounded. The case gapes at both ends.
The external ligament is a short, brown band behind the vertebrae. The area is a narrow depression in the dorsum. In the left valve there are two closely spaced cardinal teeth, as well as a long, anterior lateral tooth and a protruding posterior lateral tooth that is almost as long as the cardinal teeth. In the right valve there is only one cardinal tooth standing vertically on the lock plate, as well as a long anterior lateral tooth and a short, peg-shaped posterior lateral tooth. In both valves, a longitudinal rib runs inside from the vertebra to behind the anterior sphincter. There are two sphincters, the front one is long and extends below the vertebrae. The posterior sphincter is semicircular. The mantle bay is only shallow.
The white to slightly brownish skin is thin-walled and brittle and breaks easily. The ornamentation consists of fine growth strips parallel to the edge. A few fine radial lines emanate from the vertebra and extend to the middle third of the ventral margin. The shiny periostracum is greenish yellow to yellowish, the posterior dorsal area is beige in color. The inner edge of the case is smooth. The inside of the bowl is glossy white.
The soft body is light yellowish, the coat has a slightly reddish tint. The edges of the coat are fringed. The reddish colored siphons are short and not grown together over the greater part of their length. The purple-red foot is stretched out club-shaped.
Similar species
The translucent vaginal clam ( Phaxas pellucidus ) has a straight back and a slightly curved belly. The penknife clam differs from the Ensis species, which are similar in outline , in that the vertebrae are almost in the middle.
Geographical distribution and habitat
The distribution area of the species extends from Norway to Senegal (West Africa) and the Mediterranean .
It lives vertically with the front end down in tunnels in sandy sediments. It occurs from the low water line to about 80 meters water depth.
Taxonomy
Carl von Linné described the species as legumes in 1758 . It is the type species of the genus Pharus Gray, 1840.
supporting documents
literature
- S. Peter Dance, Rudo von Cosel (arrangement of the German edition): The great book of sea shells. 304 p., Verlag Eugen Ulmer, Stuttgart, 1977 ISBN 3-8001-7000-0 (p. 263)
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 247)
- 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. 144)
- Guido Poppe. Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 108)
On-line
- Marine Bivalve Shells of the British Isles: Pharus legumen (Linnaeus, 1758) (site of the National Museum Wales, Department of Natural Sciences, Cardiff)
- Marine Species Identification Portal: Pharus legumen (Linné, 1758)
Individual evidence
- ^ Carl von Linné: Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Pp. 1-824, Holmia / Stockholm, Salvius, 1758. Online at www.biodiversitylibrary.org (p. 672).
- ↑ MolluscaBase: Pharus legumen (Linnaeus, 1758)
