Opisthias is a genus of sphenodont reptile. The type species, Opisthias rarus, is known from the Late Jurassic (Kimmeridgian-Tithonian) of western North America.[2][3]
Opisthias Temporal range: Berriasian record
Possible | |
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Jaw of Opisthias rarus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Rhynchocephalia |
Clade: | †Opisthodontia |
Genus: | †Opisthias Gilmore 1909 |
Type species | |
Opisthias rarus Gilmore, 1905[1]
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Opisthias is primarily known from remains found in the Late Jurassic of the United States, with remains found in the Morrison Formation (Colorado, Utah, and Wyoming),[2][3][1] present in stratigraphic zones 2 and 4–6.[4] Other remains suggested to be closely related to Opisthias are also known from the Late Jurassic Alcobaça Formation of Portugal.[5][6] A undescribed crushed skull (DINO 16454) from the Morrison Formaiton has been attributed to this genus by some sources, though this has been strongly disputed by others.[7]
A lower jaw is also known from the Berriasian aged Lulworth Formation of the United Kingdom, which appears to be distinct from the type North American species.[8] A fragmentary dentary possibly attributable to Opisthias is also known from the Berriasian aged Angeac-Charente bonebed in France.[9]
Opisthias has been interpreted as a generalist, with its tooth morphology indicating had an ability to process plant material.[10]