Trigoniida is an order of medium-sized saltwater

clam 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 shel ...

s, marine bivalve molluscs. Within the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

the occurrence of this order is widespread, ranging from the Devonian

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

to Recent. The diagnostic feature for the order is the unique and complex dentition of the shell, (i.e. the interior hinge teeth that articulate the two valves). The dentition is particularly elaborate within the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

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. ...

. Bieler, Carter, & Coan (2010) included the following families and superfamilies in Trigoniida. Taxa marked with a † are extinct with the only extant family in the order being

. Trigoniida *† Beichuanioidea Liu & Gu, 1988 **† Beichuaniidae Liu & Gu, 1988 *† Megatrigonioidea Van Hoepen, 1929 **†

Megatrigoniidae '' Megatrigoniidae '' is an extinct family of fossil saltwater clams, marine bivalve molluscs in the subclass Palaeoheterodonta. This family of bivalves is known in the fossil record from the Jurassic period, Tithonian age, to the Cretaceous peri ...

Van Hoepen, 1929 **† Iotrigoniidae Savelive, 1958 **† Rutitrigoniidae Van Hoepen, 1929 *† Myophorelloidea Kobayashi, 1954 **† Myophorellidae Kobayashi, 1954 **† Buchotrigoniidae Leanza, 1993 **† Laevitrigoniidae Savelive, 1958 **† Vaugoniidae Kobayashi, 1954 *

Trigonioidea Trigonioidea is superfamily of medium-sized saltwater clams, marine bivalve molluscs. Within the fossil record the occurrence of this superfamily is widespread, ranging from the Devonian Period to Recent. The diagnostic feature for the superfam ...

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 ...

, 1819 **

, 1819 **† Eoschizodidae Newell & Boyd, 1975 (syn: Curtonotidae) **†Groeberellidae Pérez, Reyes, & Danborenea 1995 **†Myophoriidae Bronn, 1849 (syn: Cytherodontidae, Costatoriidae, Gruenewaldiidae) **†Prosogyrotrigoniidae Kobayashi, 1954 **†Scaphellinidae Newell & Ciriacks, 1962 **†Schizodidae Newell & Boyd, 1975 **†Sinodoridae Pojeta & Zhang, 1984

References

Trigoniida, Extant Devonian first appearances Prehistoric bivalves Bivalve orders {{paleo-bivalve-stub