Exogyra
Extinct genus of bivalves
Exogyra is an extinct genus of marine oysters that belongs to the family Gryphaeidae (honeycomb oysters). These bivalves were cemented by the more cupped left valve. The right valve is flatter, and the beak is curved to one side. Exogyra lived on solid substrates in warm seas during the Jurassic and Cretaceous periods.
01Taxonomy
The former subgenus Exogyra (Aetostreon) Bayle, 1878, is sometimes considered a separate genus due to a lack of the fine set of parallel ribs (chomata) separated by pits on the inner surface of the valves (which is present in the nominate subgenus).
02Species
- Exogyra africana Say, 1820
- Exogyra aquillana Stephenson, 1953
- Exogyra arietina Roemer, 1849
- Exogyra callophyla Ihering, 1903
- Exogyra cancellata Stephenson, 1914
- Exogyra clarki Shattuck, 1903
- Exogyra columbella Meek, 1876
- Exogyra contorta Eichwald, 1868
- Exogyra costata Say, 1971
- Exogyra davidsoni Whidborne, 1883
- Exogyra erraticostata Stephenson
- Exogyra fimbriata Conrad, 1855
- Exogyra flabellata (Goldfuss, 1833)
- Exogyra ganhamoroba Maury, 1936
- Exogyra guadalupae Whitney, 1937 (thesis)
- Exogyra haliotoidea Maury, 1936
- Exogyra laevigata J. de C. Sowerby, 1829
- Exogyra laeviuscula Roemer, 1849
- Exogyra lancha Stoyanow, 1949
- Exogyra levis Stephenson, 1952
- Exogyra mutatoria White, 1887
- Exogyra paupercula Cragin, 1893
- Exogyra plexa Cragin, 1893
- Exogyra potosina Castillo and Aguilera, 1895
- Exogyra ponderosa Roemer, 1849
- Exogyra praevirgula Douville & Jourdy, 1924
- Exogyra quitmanensis Cragin, 1893
- Exogyra sergipensis Maury, 1936
- Exogyra sigmoidea Reuss, 1844
- Exogyra solea Muller, 1910
- Exogyra texana Roemer, 1849
- Exogyra upatoiensis Stephenson, 1914
- Exogyra whitneyi Bose, 1910
- Exogyra woolmani Richards, 1947
03Distribution
Fossils of Exogyra have been found in:
- Jurassic
Afghanistan, Chile, China, Eritrea, Ethiopia, France, Germany, India, Kenya, Poland, Portugal, Somalia, Spain, Tanzania, the United Kingdom, and Yemen.
- Cretaceous
Afghanistan, Algeria, Argentina, Brazil, Bolivia, Canada (British Columbia), Bulgaria, Chile, Colombia (Hiló Formation, Tolima, Macanal and Chipaque Formations, Eastern Ranges), Cuba, the Czech Republic, Egypt, Ethiopia, France, Germany, Greenland, Hungary, India, Iran, Israel, Italy, Jordan, Lebanon, Libya, Madagascar, Mexico, Morocco, Mozambique, New Zealand, Nigeria, Oman, Pakistan, Peru, Poland, Portugal, Serbia and Montenegro, Slovakia, South Africa, Spain, Sweden, Switzerland, Tanzania, Trinidad and Tobago, Tunisia, Turkey, USSR, Ukraine, the United Kingdom, United States (Alabama, Arizona, Arkansas, California, Colorado, Delaware, Georgia, Maryland, Minnesota, Mississippi, Missouri, Montana, New Jersey, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Utah, Wyoming), Venezuela, and Yemen.
Sources and credits
This article is adapted from the Wikipedia article “Exogyra”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Exogyracostata.JPG by Wilson44691, Public domain
- Exogyra costata Prairie Bluff Fm Maastrichtian.JPG by Wilson44691, CC0
Fathomly is not affiliated with or endorsed by the Wikimedia Foundation. Spotted a problem? Tell us.