Limopsis tenella

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Limopsis tenella
Systematics
Pteriomorphia
Order : Arcida
Superfamily : Limopsoidea
Family : Limopsidae
Genre : Limopsis
Type : Limopsis tenella
Scientific name
Limopsis tenella
Jeffreys , 1876

Limopsis tenella is a shell - type from the family of Limopsidae in the order of Arcida .

features

The equally flattened, slightly flattened case has a maximum length of 25 mm. It is very obliquely egg-shaped in outline, the rear part of the housing is greatly elongated. As a result, the housing is very clearly asymmetrical, and the small vortices are located in front of the center line of the housing. It's a little taller than it is long. The dorsal margin is short and straight, the posterior dorsal margin is slightly longer than the anterior dorsal margin and about the same length. The posterior dorsal margin merges with the broadly rounded posterior margin at a very flat angle. The transition from the anterior dorsal margin to the anterior margin is also very flat-angled, only very slightly steeper than the posterior transition. The front edge is slightly less arched than the rear edge. The ventral margin is well arched. The dorsal field between the vertebrae is sunk flat.

The ligament is very small and extends in front of and behind the vertebrae. The small, triangular resilium sits in a shallow pit (resilifer) between the vertebrae. The taxodontic lock plate is wide; the upper edge is straight and the lower edge is angled flat. The lock has two series of strong teeth, one of which is narrow. and comparatively broad toothless areas are separated from each other. In both series there are four to five straight teeth that diverge slightly outwards. The two sphincters are unequal in size. The anterior sphincter is only about half the size of the posterior sphincter and sits directly under the front end of the lock plate. The posterior sphincter, on the other hand, is slightly above the middle of the posterior margin. The surface line is not indented.

The aragonitic shell is moderately thick and brittle. The ornamentation consists only of somewhat irregular growth lines and a few radial lines in the rear part of the case. The straw-yellow to yellow-brown periostracum is drawn out into long, fine bristles that lie flat against the shell. They form a wide, protruding seam on the edge of the housing. The skin is whitish, the inner surface is whitish and shiny. The inner edge of the case is smooth.

Geographical distribution, habitat and way of life

The species is likely to be a cosmopolitan . It occurs only in the deep sea, in Porcupine Bay from about 2,600 m to 4,900 m water depth. The maximum distribution there is between 2,700 and 2,800 m water depth. In the Gulf of Mexico, however, it has already been found at a depth of only 360 m.

The animals live half buried in the sediment and are attached to a sediment particle with a single thread of byssus . They are suspension filterers .

Taxonomy

The taxon was proposed as Limopsis tenella by John Gwyn Jeffreys in 1876 . It is widely accepted as a valid taxon. Synonyms are: Limopsis plana AE Verrill, 1882, Limopsis pelagica EA Smith, 1885, Limopsis profundicola Verrill & Bush, 1898, Limopsis transversa Locard, 1898 and Limopsis guineensis Thiele, 1931.

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. 28)
  • Graham Oliver, John A. Allen: The Functional and Adaptive Morphology of the Deep-Sea Species of the Family Limopsidae (Bivalvia: Arcoida) from the Atlantic. Philosophical Transactions of the Royal Society of London Series B. 291: 77-125, 1980, JSTOR 2395366 .

Individual evidence

  1. ^ A b c Marine Bivalve Shells of the British Isles: Limopsis tenella Jeffreys, 1876 (website of the National Museum Wales, Department of Natural Sciences, Cardiff)
  2. ↑ P. Graham Oliver: Deep-water Thyasiridae (Mollusca: Bivalvia) from the Oman Margin, Arabian Sea, new species and examples of endemism and cosmopolitanism. Zootaxa, 3995 (1) 2015 doi : 10.11646 / zootaxa.3995.1.21
  3. ↑ Celia Olabarria: Patterns of bathymetric zonation of bivalves in the Porcupine Seabight and adjacent Abyssal plain, NE Atlantic. Deep-Sea Research I, 52: 15-31, 2005 doi : 10.1016 / j.dsr.2004.09.005
  4. ↑ Donna D. Turgeon, William G. Lyons, Paula Mikkelsen, Gary Rosenberg, Fabio Moretzsohn: Bivalvia (Mollusca) of the Gulf of Mexico . In: Felder, DL, DK Camp (ed.): Gulf of Mexico-Origins, Waters, and Biota . Volume 1 Biodiversity. Pp. 711-744, Texas A&M University Press, College Station, Texas 2009 PDF (ResearchGate).
  5. ^ John Gwyn Jeffreys, New and peculiar Mollusca of the Pecten, Mytilus and Arca families, procured in the Valorous expedition. Annals and Magazine of Natural History. 4. series, 18: 424-436, London 1876. Online at www.biodiversitylibrary.org (p. 433)
  6. ↑ a b MolluscaBase: Limopsis tenella Jeffreys, 1876