''Trigonia'' is an extinct genus of saltwater clams, fossil

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 ...

mollusk in the family Trigoniidae. The fossil range of the genus spans the Paleozoic, Mesozoic and Paleocene of the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

, from 298 to 56 Ma.

Description

The genus ''Trigonia'' is the most readily identifiable member of the family Trigoniidae, having a series of strong ribs or costae along the

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

part of the shell exterior. They are the first representatives of the family to appear in the Middle Triassic ( Anisian) of Chile and New Zealand. The first European examples (''Trigonia costata'' Parkinson) appear in the Lower Jurassic ( Toarcian) of Sherborne, Dorset and Gundershofen, Switzerland.

Species

The following ''Trigonia'' species have been described:''Trigonia''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org * ''T. analoga'' * ''T. antiqua'' * ''T. castani'' * ''T. castrovillensis'' * ''T. coqueiroensis'' * ''T. costata'' * ''T. cragini'' * ''T. depauperata'' * ''T. eufaulensis gabbi'' * ''T. eufaulensis moorei'' * ''T. guildi'' * ''T. hemisphaerica'' * ''T. imbricata'' * ''T. interlaevigata'' * ''T. intersitans'' * ''T. kitchini'' * ''T. maastrichtiana'' * ''T. maloneana'' * ''T. marginata'' * ''T. mearnsi'' * ''T. montanaensis'' * ''T. orientalis'' * ''T. papuana'' * ''T. picteti'' * ''T. plana'' * ''T. pseudocaudata'' * ''T. pseudocrenulata'' * ''T. pullus'' * ''T. rebouli'' * ''T. reesidei'' * ''T. resoluta'' * ''T. reticulata'' * ''T. saavedra'' * ''T. semiculta'' * ''T. somaliensis'' * ''T. stantoni'' * ''T. stolleyi'' * ''T. suborbicularis'' * ''T. sulcata'' * ''T. taffi'' * ''T. thierachensis'' * ''T. undulatocostata'' * ''T. vyschetzkii'' * ''T. weaveri''

Distribution

Fossils of ''Trigonia'' have been registered in: ;Permian Bolivia (

Copacabana Formation Copacabana most commonly refers to: * Copacabana, Rio de Janeiro, Brazil. Copacabana may also refer to: Places * Copacabana, Catamarca, Argentina * Copacabana, Bolivia * Copacabana Municipality, Bolivia * Fort Copacabana, Brazil * Copacaban ...

) ;Triassic Austria, China, Italy, the Russian Federation, United States (Alaska, Idaho), and Vietnam. ;Jurassic Afghanistan, Argentina, Canada (Alberta, British Columbia, Yukon), Chile, Colombia (

Valle Alto Formation The Valle Alto Formation ( es, Formación Valle Alto, Jva) is a geological formation of the Central Ranges of the Colombian Andes. The formation is composed of shales, sandstones and conglomerates and dates to the Late Jurassic period. Ammonit ...

, Caldas),Mojica, 1984, p.132 Egypt, Ethiopia, France, Germany, Greenland, India, Iran, Japan, Kenya, Luxembourg, Madagascar, Morocco, New Zealand, Poland, Portugal, the Russian Federation, Saudi Arabia, Somalia, Spain, Tanzania, Thailand, Tunisia, the United Kingdom, United States (Alaska, California, Idaho, Montana, Nevada, Oregon, Texas, Utah, Wyoming), and Yemen. ;Cretaceous Afghanistan, Algeria, Antarctica, Argentina, Armenia, Australia, Brazil, Bulgaria, Canada (British Columbia), Chile, Colombia ( Yuruma Formation, La Guajira,

Macanal Formation The Macanal Formation or Macanal Shale ( es, (Formación) Lutitas de Macanal, Kilm, K1m) is a fossiliferous geological formation of the Altiplano Cundiboyacense and Tenza Valley in the Eastern Ranges of the Colombian Andes. The predominantly orga ...

, Eastern Ranges),Piraquive et al., 2011, p.204 Egypt, France, Germany, Greenland, Hungary, Italy, Lebanon, Mexico, the Netherlands, New Zealand, Papua New Guinea, Peru, Portugal, Serbia and Montenegro, South Africa, Spain, Switzerland, Tanzania, Turkmenistan, Russian Federation, Ukraine, the United Kingdom, United States (Arizona, California, Delaware, Mississippi, New Jersey, North Carolina, Tennessee, Texas), Venezuela, and Yemen. ;Paleocene Argentina (

Cerro Dorotea Formation Cerro is Spanish for "hill" or "mountain". Toponyms ;Bolivia: * Cerro Rico, the "Rich Mountain" containing silver ore near Potosi, Bolivia ;Brazil: *Cerro Branco, a municipality of Rio Grande do Sul *Cerro Grande, Rio Grande do Sul, a municip ...

)

References

Bibliography

* *

External links

Sepkoski's Online Genus Database
{{Taxonbar, from=Q38335712 Trigoniidae Paleozoic bivalves Permian animals of South America Permian Bolivia Mesozoic bivalves Mesozoic animals of Africa Mesozoic animals of Asia Mesozoic animals of Europe Mesozoic animals of Oceania Mesozoic animals of North America Mesozoic animals of South America Jurassic Argentina Cretaceous Argentina Cretaceous Brazil Jurassic Chile Cretaceous Chile Jurassic Colombia Cretaceous Colombia Fossils of Colombia Cretaceous Peru Cretaceous Venezuela Paleogene bivalves Paleogene animals of South America Paleogene Argentina Permian first appearances Paleocene genus extinctions Cretaceous–Paleogene boundary Fossil taxa described in 1789 Anisian life Prehistoric bivalve genera Fossils of Serbia