Lutraria angustior
| Lutraria angustior | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
![Lutraria angustior (from GB Sowerby II, 1859: Plate 4, Fig.1 [1])](https://de.wikipedia.org/wiki/Datei:GBSowerbyII_1859_pl4_fig1_Lutraria_angustior.png)
Lutraria angustior (from GB Sowerby II, 1859: plate 4, fig. 1) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Lutraria angustior | ||||||||||||
| Philippi , 1844 |
Lutraria lutraria is a type of mussel from the family of trough mussels (Mactridae).
features
The same-folding, not inflated case is very large. There are very different specifications in the literature about the maximum length, ranging from about 8 cm to 20 cm. It is unequal, with the vertebrae in front of the midline (at about a third of the length of the case from the front end). The housing outline is elliptical, the length / height ratio is about 2.1. The posterior dorsal margin is long and slightly convex, and slopes down to the rounded posterior end. The anterior dorsal margin is shorter, very flat convexly arched to almost straight, and slopes slightly more steeply towards the anterior end. The transition to the front edge is slightly angled. The front end is slightly more rounded than the rear end. The ventral edge has an almost straight to even very slightly concave area in the middle. The closed housing gapes at the front and rear. The gaping opening at the rear end is much larger than the small gaping opening at the front end. The flaps only close really tightly in the lock area and in the middle part of the ventral margin.
The ligament is external and internal. The external ligament behind the vertebra is a small, dark brown, deeply sunk band. The internal ligament sits in a large, spoon-shaped process ( chondrophor ). The top of the pit sits just below the vertebrae. The left flap shows two cardinal teeth forming an inverted V-shaped structure just in front of the ligament fossa. There is also a very small, thin lateral tooth between the ligament pit and the two large cardinal teeth, which breaks off very easily. Close to the edge of the case and running parallel to it, there are small, lamellar posterior teeth in front and behind. In the right valve there are two cardinal teeth and a weakly developed, lamellar, posterior lateral tooth. The mantle is deep and deeply indented at the back, the apex of the bay is approximately below the eddy. At the ventral edge, the mantle edge and the ventral part of the mantle bay are largely fused or coincide. There are two sphincters of approximately the same size; the anterior sphincter is elongated, the posterior sphincter more rounded and ovoid.
The whitish to slightly yellowish skin is thick-walled, firm but brittle. The ornamentation consists of fine concentric lines and pits, which can be somewhat irregular and also coarser. The periostracum is a thin, light brown coating. The inner edge of the case is smooth, the insides are glossy white.
Similar species
The elongated otter mussel ( Lutraria magna ) cannot be confused with Lutraria angustior due to its very peculiar shape . In contrast, the otter clam ( Lutraria lutraria ) is very similar. Lutraria angustior is somewhat slimmer, i.e. somewhat wider in relation to the height, and the anterior dorsal margin is flatter. In addition, the edge of the jacket and the ventral part of the jacket are largely separate. The transition from the anterior dorsal margin to the anterior margin is often slightly angled.
Geographical distribution, habitat and way of life
The distribution area of the species extends from the English Channel south to the Mediterranean Sea and West Africa.
It prefers mixed, soft sediments from the tidal range to about 50 meters water depth. The animals dig themselves deep and vertically and only the siphons reach the sediment surface.
Taxonomy
The taxon was established by Rudolph Amandus Philippi as Lutraria elliptica var. Angustior . The name of the variety is also available as a species name. MolluscaBase treats the taxon as a valid species.
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. 143/4)
- Guido Poppe, Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 p., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 100)
On-line
- Marine Bivalve Shells of the British Isles: Lutraria angustior Philippi, 1844 (site of the National Museum Wales, Department of Natural Sciences, Cardiff)
- Lutraria angustior Philippi, 1844 Marine Species Identification Portal
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 4)
- ^ 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. 143/4)
- ^ Peter J. Hayward: Handbook of the marine fauna of north-west Europe. X + 800 pp., Oxford, Oxford Univ. Press, 1995; Preview in Google Books
- ↑ Rudolphus Amandus Philippi: Enumeratio molluscorum Siciliae cum viventium tum in tellure tertiaria fossilium quae in itinere suo observavit. Volume secundum continens addenda et emendanda, nec non comparationem faunae recentis Siciliae cum faunis aliarum terrarum et com fauna periodi tertiariae. SI-IV, pp.1-303, Plates XIII-XXVIII [= 13-28]. Halae / Halle, Anton 1844. Online at www.biodiversitylibrary.org (p. 7)
- ^ MolluscaBase: Lutraria angustior Philippi, 1844
