Atrina

from Wikipedia, the free encyclopedia
Atrina
Fragile pen shell (Atrina fragilis)

Fragile pen shell ( Atrina fragilis )

Systematics
Subclass : Autolamellibranchiata
Subclass : Pteriomorphia
Order : Ostreida
Superfamily : Pinnoidea
Family : Pen clams (Pinnidae)
Genre : Atrina
Scientific name
Atrina
Gray , 1842

Atrina is a shell - genus of the family of plug shells (Pinnidae) from the order of Ostreida . The earliest evidence of the genus comes from the Middle Triassic .

features

The housings of the Atrina species, which have the same flaps, are ham-shaped, paddle-shaped to broadly fan-shaped and are up to 480 mm long. They are strongly unequal, the vertebrae sit at the front (pointed) end. The rear end is rounded more or less convexly. The housings stick with the pointed front end down in the soft sediment. The rear (upper), constantly gaping end protrudes about a third out of the sediment or is almost flush with the sediment surface. The housings are wide to very wide and flattened. A longitudinal keel is missing. At the front end, which is stuck in the sediment, there is another gaping ventrally, at which the byssus emerges. The lock has no teeth. The ligament extends over almost the entire length of the dorsal margin and lies in a groove.

The shell is made up of a mineral component and an organic periostracum . It is comparatively thin and fragile, but also flexible to a certain extent. The mineral shell consists of an outer, calcitic prism layer and an inner, aragonitic mother-of-pearl layer .

The surface is provided with ribs, or sharp scales arranged in a row or scales open to the rear, or also approximately smooth with more or less distinct growth stripes.

The anterior sphincter sits near the anterior end (below) and is relatively small. The posterior sphincter, on the other hand, is very large. It sits somewhat ventrally in relation to the width near the surface line, which is however clearly set back from the rear (upper) end.

Similar genera

In the pinna the inner layer of mother-of-pearl is divided by a longitudinal furrow into a dorsal and a ventral lobe, while in the atrina the layer of mother-of-pearl is uniform. The Atrina does not have the typical longitudinal keel in the middle of the case. In streptopinna , the mother-of-pearl layer is reduced to a dorsal lobe. The cases are a bit irregular.

Geographical distribution and habitat

The distribution area of ​​the genus is mainly in the Indo-Pacific. Only eight species are also found in the Atlantic, three of which are in the Eastern Atlantic and the Mediterranean. The animals anchor themselves with byssus threads in the sediment or a solid particle (stone, casing) in the sediment. The rear (upper) end is almost flush with the sediment surface. Most species live in shallow waters to a depth of a few tens of meters. The fragile pen shell ( Atrina fragilis ), however, comes in much greater water depths (approx. 150 to 600 meters).

Taxonomy

The taxon was established by John Edward Gray in 1842. Type species is Pinna nigra Dillwyn, 1817, a more recent synonym of Pinna vexillum Born, 1778. The MolluscaBase and the Paleobiology Database assign the following recent and fossil species to the genus:

MolluscaBase recorded as the synonym Pennaria Mörch, 1853, a younger homonym of Pennaria Blainville, 1818 (Annelida). The genus Atrina is divided by Peter Schultz and Markus Huber into the three subgenera Atrina (Atrina) , Atrina (Australopinna) Schultz & Huber, 2013 and Atrina (Servatrina) Iredale, 1939.

supporting documents

literature

  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 41)
  • Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Bivalvia 1. XXXVIII, 489 pp., New York, 1969 (pp. N283).
  • 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. 42)

Individual evidence

  1. ^ A b Thomas R. Waller, George D. Stanley: Middle Triassic Pteriomorphian Bivalvia (Mollusca) from the New Pass Range, West-Central Nevada: Systematics, Biostratigraphy, Paleoecology, and Paleobiogeography. Journal of Paleontology Memoir, 61: 1-64, 2005, JSTOR 4095819
  2. ^ Nico AJM Sommerdijk, Maggie Cusack: Biomineralization: Crystals competing for space. Nature Materials, 13: 1078-1079, 2014 doi : 10.1038 / nmat4147
  3. ^ John Edward Gray: Eastern Zoological Gallery. Synopsis of the Contents of the British Museum, 44: 22-92, London 1842 Online at www.forgottenbooks.com (p. 83)
  4. ↑ a b MolluscaBase: Atrina Gray, 1842
  5. ^ Paleobiology Database: Atrina Gray, 1842
  6. ↑ Yawuz Okan, İzzet Hoşgör: Early Eocene (middle-late Cuisian) Molluscs Assemblage from the Harpactocarcinid Beds, in the Yoncalı Formation of the Çankırı Basin, Central Anatolia, and Implications for Tethys Paleogeography. Geological Bulletin of Turkey 52 (1): 1-30, 2009 PDF
  7. ↑ a b c d Frank E. Eames: Tertiary Marine Pelecypods of California and Baja California: Nuculidae through Malleidae. United States Geological Suvery Professional Paper 1228-A: A1-A108, 1983 Online at Google Books
  8. ↑ a b c d e f Robert Marquet: A revision of the Caenozoic Pinnidae from Belgium (Mollusca, Bivalvia). Bulletin de l'Institut Royal des Sciences Naturelles de Belgiques Sciences de la Terre, Bulletin van het Koninklijk Belgisch Instituut voor Natuurwetenschappen, Aardwetenschappen, 65: 241-256, 1995 PDF
  9. ^ Stenzel, Krause, & Twining: Pelecypoda from the Type Locality of the Stone City Beds (middle Eocene) of Texas. University of Texas Publication 5704, 1957
  10. Jump up ↑ a b c d e Katherine VW Palmer, Doris C. Brann: Catalog of the Paleocene and Eocene Mollusca of the Southern and Eastern United States: Part I. Pelecypoda, Amphineura, Pteropoda, Scaphopoda, and Cephalopoda. Bulletins of American Paleontology, 48 (218): 1-443, 1965 online at www.archive.org
  11. ^ Peter Schultz, Markus Huber: Revision of the worldwide Recent Pinnidae and some remarks on fossil European Pinnidae. Acta Conchyliorum, 13: 164 S., Hackenheim, ConchBooks, 2013

Web links

Commons : Atrina  - collection of images, videos and audio files