Rifle clams

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Rifle clams
Systematics
Subclass : Heterodonta
Euheterodonta
Superordinate : Anomalodesmata
Order :
Superfamily : Pandoroidea
Family : Rifle clams
Scientific name
Pandoridae
Rafinesque-Schmaltz , 1815

The rifle shells (Pandoridae) are a shell - family from the large group of Anomalodesmata . The oldest members of the family come from the Eocene .

features

The elongated housings are clearly unequal and strongly narrowed at the sides (narrow). They become several inches long. The right flap is mostly flat, the left flap more or less strongly curved; it usually clearly towers above the right valve. The casing is also asymmetrical, with the prominent vertebrae sitting in front of the center line. It is mostly boat-shaped in outline. the ventral margin is very broadly rounded. The rear edge is often drawn out into a beak. The rear part of the case is often twisted a little to the left. The posterior dorsal margin is concave, so the posterior end rises to the level of the vertebrae. The anterior dorsal margin is convex and sloping flat.

A ligament is only weakly developed. It is thin and lies internally in front of and behind the vertebra. An actual lock plate is missing. There are few teeth or the lock is toothless. The siphons are short. The two sphincters are roughly the same size. In the adult stage there is no (longer) byssus. The surface line is not indented.

The shell is aragonitic with an inner layer of layered mother-of-pearl, a middle layer of lenticular mother-of-pearl and an outer prismatic layer. The ornamentation consists of fine to somewhat coarser growth strips parallel to the edge. The periostracum is thin with occasional fine lines.

Geographical distribution, habitat and way of life

The species of the families occur predominantly in the tropical and subtropical seas and with some species also in temperate latitudes.

Most species dig shallow in the sediment or lie stationary on the sediment.

Taxonomy

The taxon was set up in 1815 by Constantine S. Rafinesque-Schmaltz as the subfamily Pandoracia Les Pandoracées. It is now recognized as a taxon in superfamily and family rank. According to MolluscaBase, the family currently includes the following genera:

supporting documents

literature

  • Eugene V. Coan, Paul Valentich-Scott: Bivalve Seashells of Tropical West America marine Bivalve mollusks from Baja california to Northern Perú. Part 2. Santa Barbara Museum of Natural History, Santa Barbara 2012 ISBN 978-0-936494-43-2 (p. 954)
  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 228)
  • 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. 157)
  • Myra Keen: Family Pandoridae Rafinesque, 1815. In: Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Bivalvia 2. S.N843 / 44, New York, 1969.

Individual evidence

  1. ↑ Constantine S. Rafinesque-Schmaltz Online at www.biodiversitylibrary.org (p. 146)
  2. ↑ MolluscaBase: Pandoridae Rafinesque, 1815