Trigoniida is an
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
of medium-sized saltwater
clams,
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 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. Within the
fossil record the occurrence of this order is widespread, ranging from the
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
Period to
Recent
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together ...
.
The diagnostic feature for the order is the unique and complex
dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolo ...
of the shell, (i.e. the interior hinge teeth that articulate the two valves). The dentition is particularly elaborate within the
family Trigoniidae.
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
Trigoniidae.
Trigoniida
*†
Beichuanioidea Liu & Gu, 1988
**†
Beichuaniidae Liu & Gu, 1988
*†
Megatrigonioidea Van Hoepen, 1929
**†
Megatrigoniidae 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 Lamarck, 1819
** Trigoniidae Lamarck, 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
Extant Devonian first appearances
Prehistoric bivalves
Bivalve orders
{{paleo-bivalve-stub