''Plagiostoma'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of fossil saltwater clams, marine bivalve

mollusk 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 e ...

s in the family

Limidae The Limidae or file shells are members of the only family of bivalve molluscs in the order Limida. The family includes 130 living species, assigned to 10 genera. Widely distributed in all seas from shallow to deep waters, the species are usua ...

, the file clams.

Species

*''Plagiostoma aurita'' Popov 1964 *''Plagiostoma bellula'' Morris and Lycett 1853 *''Plagiostoma delettrei'' Coquand 1852 *''Plagiostoma deltoideum'' Girty 1909 *''Plagiostoma dianense'' Guo 1985 *''Plagiostoma euximium'' Bayle 1878 *''Plagiostoma gejiuense'' Guo 1985 *''Plagiostoma gigantea'' Boehm 1911 *''Plagiostoma giganteum'' Sowerby 1814 *''Plagiostoma harronis'' Dacque 1905 *''Plagiostoma hermanni'' Voltz 1830 *''Plagiostoma immensum'' Repin 2013 *''Plagiostoma inversa'' Waagen 1881 *''Plagiostoma lenaensis'' Kurushin 1998 *''Plagiostoma malinovskyi'' Bytschkov 1976 *''Plagiostoma nudum'' Parona 1889 *''Plagiostoma popovi'' Kurushin 1985 *''Plagiostoma punctatum'' Sowerby 1818 *''Plagiostoma rodburgensis'' Whidborne 1883 *''Plagiostoma semicircularis'' Goldfuss 1835 *''Plagiostoma striatum'' Schlotheim 1820 *''Plagiostoma sublaeviusculum'' Krumbeck 1905 *''Plagiostoma subsimplex'' Thomas and Peron 1891 *''Plagiostoma subvaloniense'' Krumbeck 1923 *''Plagiostoma tihensis'' Abbass 1962

Distribution

This cosmopolitan genus occurs in Mid Triassic to

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', th ...

strata (from 295.0 to 66.043 Ma.) Plagiostoma in Fossilworks
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Description

These bivalves are epifaunal byssate suspension feeders of up to 12 cm in size. The shells are obliquely ovate, moderately inflated, with obtuse posterior and smaller anterior wings. ''Plagiostoma giganteum'' is a well-known fossil bivalve which occurs in the

Blue Lias The Blue Lias is a geological formation in southern, eastern and western England and parts of South Wales, part of the Lias Group. The Blue Lias consists of a sequence of limestone and shale layers, laid down in latest Triassic and early Jurassi ...

formation in various parts of the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

, although it is geographically widespread and has also been found in the Triassic of the United Kingdom.fossilworks - †Plagiostoma giganteum Sowerby 1814 (file clam)
/ref>

Gallery

File: Limidae - Plagiostoma punctatum.JPG, ''Plagiostoma punctatum'' File:Plagiostoma striatum u. Trochiten 240410.jpg, ''Plagiostoma striatum'' File:Plagiostoma lineatum Obere Schaumkalkbank 040410.jpg, ''Plagiostoma lineatum'' File:Plagiostoma giganteum multiview.png, ''Plagiostoma giganteum''

References

Limidae Prehistoric bivalve genera Middle Triassic genus first appearances Ladinian genera Carnian genera Norian genera Rhaetian genera Hettangian genera Sinemurian genera Pliensbachian genera Toarcian genera Aalenian genera Bajocian genera Bathonian genera Callovian genera Oxfordian genera Kimmeridgian genera Tithonian genera Berriasian genera Valanginian genera Hauterivian genera Barremian genera Aptian genera Albian genera Cenomanian genera Late Cretaceous genus extinctions Fossils of Uzbekistan Bissekty Formation {{paleo-bivalve-stub