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 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.
Species The following Trigonia species have been described:Trigonia at Fossilworks.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)
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),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, 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)
References
Bibliography
External links Sepkoski's Online Genus Database