Trigonia

Extinct genus of bivalves

Trigonia Temporal range: Permian-Paleocene ~298–56 Ma PreꞒ Ꞓ O S D C P T J K Pg N

A fossil shell of T. interlaevigata from Germany, of Jurassic age
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Trigoniida
Family:	Trigoniidae
Subfamily:	Trigoniinae
Genus:	†Trigonia Bruguière, 1789
Species
See text

Diagram of *Trigonia costata* James Parkinson, showing main morphological features of the shell exterior;
a) Anterior; p) Posterior; d) Dorsal; v) Ventral; F) Flank; A) Area; c) Costae; mc) Marginal Carina
*Trigonia costata* ranges from the Lower Jurassic (Toarcian) to Middle Jurassic (Callovian).

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.^[1]

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 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.^[2]

Species

The following Trigonia species have been described:^[1]

T. analoga
T. antiqua
T. castani
T. castrovillensis
T. coqueiroensis
T. costata^[2]
T. cragini
T. depauperata
T. eufaulensis gabbi
T. eufaulensis moorei
T. guildi
T. hemisphaerica
T. imbricata
T. interlaevigata^{[citation needed]}
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:^[1]

Permian

Bolivia (Copacabana Formation)

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, Caldas),^[3] 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, Eastern Ranges),^[4] 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)

References

^ ^a ^b ^c Trigonia at Fossilworks.org
^ ^a ^b Francis, A.O. (2000). The Palaeobiology of the European Jurassic Trigoniidae. Ph.D. thesis. University of Birmingham. pp. 1–323.
^ Mojica, 1984, p.132
^ Piraquive et al., 2011, p.204

Bibliography

Mojica, Jairo. 1984. An outline on the Jurassic in Colombia. Geología Colombiana 13. 129–136. Accessed 2017-03-31.
Piraquive, Alejandro; Juan Sebastián Díaz; Tomas Cuéllar; Germán Pardo, and Andreas Kammer. 2011. Reactivación Neógena de estructuras de rift del Cretácico Temprano asociadas con la Falla de Chámeza, Pajarito, Boyacá (Colombia): evidencias tectónicas y bioestratigráficas. Geología Colombiana 36. 197–216. Accessed 2017-08-04. Archived 2017-03-30 at the Wayback Machine