Atrina

Taxobox
name = "Atrina"


regnum = Animalia
phylum = Mollusca
classis = Bivalvia
ordo = Pterioida
familia = Pinnidae
genus = "Atrina"
genus_authority = Gray, 1847

"Atrina" is a cosmopolitan genus of bivalve molluscs characterized by elongated, wedge-shaped shells, distinguished from the genus "Pinna" by the lack of any grooves in the nacreous lining of the shell, and by the central positioning of the adductor scar.

As with other pen shells (Pinnidae) they commonly stand point-first in the sea bottom in which they live, anchored by net of byssus threads. "Atrina" is considered to represent the more primitive form within the Pinnidae; however, both genera are ancient and represented within the fossil record.

A typical species is "A. fragilis", found in British waters. "A. rigida" (Lightfoot, 1786) is found on the southeast coast of North America and in the West Indies. The type species is "A. nigra" (Dillwyn, 1817, originally "P. nigra").

References

*cite journal
last = Packard
first = Earl
coauthors = Jones, David L.
title = Cretaceous Pelecypods of the Genus Pinna from the West Coast of North America
journal = Journal of Paleontology
volume = 39
issue = 1
pages = 910–915
date = Sept. 1965
*cite web
url = http://www.manandmollusc.net/glossary.html
title = Glossary
publisher = Man and Mollusc
accessdate = 2008-01-30
*cite web
url=http://www.mitchellspublications.com/guides/shells/articles/0046/
title=American Stiff Pen Shell: Strength and Rigidity
last = Mitchell
first = Patricia B.
accessdate = 2008-01-31