''Atrina'' is a cosmopolitan

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

s belonging to the family

Pinnidae The Pinnidae are a taxonomic family of large saltwater clams sometimes known as pen shells. They are marine bivalve molluscs in the order Pteriida. Shell description The shells of bivalves in this family are fragile and have a long and triang ...

. A typical species is '' A. fragilis'', found in British waters. '' A. rigida'' (

Lightfoot Lightfoot may refer to: * Lightfoot (surname) * Lightfoot (lacrosse), Native American lacrosse player * Lightfoot, Virginia, an area of York County that is west of Williamsburg, VA * Operation Lightfoot, part of the Second Battle of El Alamein * ...

, 1786) is found on the southeast coast of North America and in the West Indies. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''A. nigra'' ( Dillwyn, 1817, originally ''P. nigra''). ''Atrina'' is considered to represent the more primitive form within the Pinnidae; however, both genera '' Pinna'' and ''Atrina'' are very ancient. The genus ''Atrina'' is represented within the fossil record from the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

period to the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

period (age range: 242.0 to 0.0 million years ago). These fossils have been found all over the world.

Description

Molluscs within this genus are characterized by elongated, wedge-shaped shells, distinguished from the genus '' Pinna'' by the lack of any grooves in the

nacre Nacre ( , ), also known as mother of pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer; it is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is f ...

ous lining of the shell, and by the central positioning of the adductor scar. As with other pen shells (

) they commonly stand point-first in the sea bottom in which they live, anchored by net of

byssus A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilid ...

threads.

Species

Species within the genus ''Atrina'' include:Fossilworks
/ref> * ''

Atrina affinis ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' Sowerby, 1821† * ''

Atrina argentea ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' Conrad, 1848† * '' Atrina assimilis'' (Reeve, 1858) * ''

Atrina chautardi ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' (Nicklès, 1953) * ''

Atrina chinensis ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. A typical species is ''Atrina fragilis, A. fragilis'', found in British waters. ''Atrina rigida, A. rigida'' (John Lightfoot FRS, Lightfoot, 1786) is found ...

'' (Deshayes, 1841) * ''

Atrina cumingii ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' (Reeve, 1858) * ''

Atrina exusta ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' (Gmelin, 1791) * ''

Atrina fragilis ''Atrina fragilis'', the fan mussel, is a species of large saltwater clam, a marine bivalve mollusc in the family Pinnidae, the pen shells. The fan mussel, ''Atrina fragilis'' is one of the largest (30 to 48 cm long) and rarest bivalve mollusc ...

'' ( Pennant, 1777) — fan mussel * ''

Atrina harrisii ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' Dall, 1898† * ''

Atrina hystrix ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' (Hanley, 1858) * ''

Atrina inflata ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' (Dillwyn, 1817) * ''

Atrina jacksoniana ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' Dall, 1898† * ''

Atrina japonica ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' (Reeve, 1858) * ''

Atrina kinoshitai ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 ...

'' Habe, 1953 * '' Atrina lischkeana'' (Clessin, 1891) * ''

Atrina magellanica ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 t ...

'' Ihering, 1907† * ''

Atrina marquesana ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. A typical species is ''Atrina fragilis, A. fragilis'', found in British waters. ''Atrina rigida, A. rigida'' (John Lightfoot FRS, Lightfoot, 1786) is found ...

'' P. W. Schultz & M. Huber, 2013 * ''

Atrina maura ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 t ...

'' (G. B. Sowerby I, 1835) * '' Atrina nigra'' (Dillwyn, 1817) * ''

Atrina oldroydii ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 t ...

'' Dall, 1901 * ''

Atrina pectinata ''Atrina pectinata'' is a species of bivalves belonging to the family Pinnidae. The species is found in the Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence ...

'' (Linnaeus, 1767) * ''

Atrina penna ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 t ...

'' (Reeve, 1858) * '' Atrina pini'' P. W. Schultz & M. Huber, 2013 * ''

Atrina piscatoria ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. A typical species is ''Atrina fragilis, A. fragilis'', found in British waters. ''Atrina rigida, A. rigida'' (John Lightfoot FRS, Lightfoot, 1786) is found ...

'' Glenn, 1904† * '' Atrina recta'' Dall, Bartsch & Rehder, 1938 * '' Atrina rigida'' (

, 1786) — stiff pen shell * ''

Atrina rosenkrantzi ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. A typical species is ''Atrina fragilis, A. fragilis'', found in British waters. ''Atrina rigida, A. rigida'' (John Lightfoot FRS, Lightfoot, 1786) is found ...

'' Schnetler & M. S. Nielsen, 2018 † * '' Atrina seminuda'' (

Lamarck Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), often known simply as Lamarck (; ), was a French naturalist, biologist, academic, and soldier. He was an early proponent of the idea that biolog ...

, 1819) — half-naked pen shell * '' Atrina serra'' (Reeve, 1858) * '' Atrina serrata'' (Sowerby, 1825) — saw-toothed pen shell * ''

Atrina squamifera ''Atrina squamifera'', one of several species known as the ''horse mussel'', is a species of Bivalvia, bivalve pen shell. It is a marine (ocean), marine mollusc in the family (biology), family Pinnidae. It is Endemism, endemic to South Africa. D ...

'' (Sowerby, 1835) * '' Atrina stephensi'' Hanna, 1926† * '' Atrina strangei'' (Reeve, 1858) * ''

Atrina talarensis ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 t ...

'' Olsson, 1928† * ''

Atrina tasmanica ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. A typical species is ''Atrina fragilis, A. fragilis'', found in British waters. ''Atrina rigida, A. rigida'' (John Lightfoot FRS, Lightfoot, 1786) is found ...

'' (Tenison Woods, 1876) * ''

Atrina teramachii ''Atrina'' is a cosmopolitan genus of bivalve molluscs belonging to the family Pinnidae. 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 t ...

'' Habe, 1953 * '' Atrina texta'' Hertlein, Hanna & A. M. Strong, 1943 * '' Atrina tuberculosa'' (G. B. Sowerby I, 1835) * '' Atrina vexillum'' ( Born, 1778) — flag pen shell * '' Atrina zelandica'' (Gray in Yate, 1835) — the horse mussel

References

* * *

External links

idscaro.net
— images Pinnidae Bivalve genera Taxa named by John Edward Gray {{bivalve-stub