''Neotrigonia'' 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 living saltwater

clams Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two she ...

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military ...

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

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

Trigoniidae Trigoniidae is a taxonomic family of saltwater clams, marine bivalve mollusks in the superfamily Trigonioidea. There is only one living genus, '' Neotrigonia'', but in the geological past this family was well represented, widespread and common. ...

, which otherwise consists only of fossil genera. For a long time the entire family was thought to be long extinct, but a living species that is now placed in this genus was discovered in 1802. At that time it was assigned to the fossil genus ''

Trigonia ''Trigonia'' is an extinct genus of saltwater clams, fossil marine bivalve mollusk in the family Trigoniidae. The fossil range of the genus spans the Paleozoic, Mesozoic and Paleocene of the Cenozoic, from 298 to 56 Ma. Description The gen ...

''. Currently, according to the World Register of Marine Species, 8 species in this genus are recognized.

Discovery of the genus

Until the beginning of the 19th century, no living species in this superfamily had ever been discovered, although numerous fossil species were known. The superfamily was well known as fossils from the Devonian to the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

Period. In 1802, however, François Péron discovered a living species in waters off the coast of

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

. In 1804,

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 biolo ...

named that species ''Trigonia margaritacea'', and Cossmann renamed the genus ''Neotrigonia'' in 1912. Today, eight living species are known to exist, all of which are found off the coast of Australia and Tasmania. ''Neotrigonia'' probably evolved from ''Eotrigonia'' (

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

) during the Miocene epoch.Francis, A.O. 2000. The Palaeobiology of the European Jurassic Trigoniidae. Ph.D. thesis, University of Birmingham, 323pp.

Species

Species within the genus ''Neotrigonia'' include: * '' Neotrigonia bednalli'' (Verco, 1907) * '' Neotrigonia gemma'' Iredale, 1924 * '' Neotrigonia jacksoni'' Morrison, 2011 * '' Neotrigonia kaiyomaruae'' Habe & Nomoto, 1976 * '' Neotrigonia lamarckii'' (Gray, 1838) * '' Neotrigonia margaritacea'' (Lamarck, 1804) * '' Neotrigonia strangei'' (A. Adams, 1854) * '' Neotrigonia uniophora'' (Gray in Jukes, 1847) Synonym * '' Neotrigonia horia'' Cotton, 195: synonym of '' Neotrigonia bednalli'' (Verco, 1907)

References

External links

PLOS paper which includes a photograph of a live individual of ''Neotrigonia lamarckii'', with the foot showing

Image showing internal soft parts of a ''Neotrigonia''

Rotterdam Museum image of a shell of ''Neotrigonia strangei''
* Bivalve genera {{bivalve-stub