Acleistorhinus

Acleistorhinus
Temporal range: Early Permian, 273.6–271.6Ma
Illustration of Acleistorhinus skull and full restoration.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Procolophonomorpha
Family: Acleistorhinidae
Genus: Acleistorhinus
Daly, 1969
Type species
Acleistorhinus pteroticus
Daly, 1969

Acleistorhinus is an extinct genus of parareptile known from the Early Permian (middle Kungurian stage) of Oklahoma. It is notable for being the earliest known anapsid reptile yet discovered. The morphology of the lower temporal fenestra of the skull of Acleistorhinus bears a superficial resemblance to that seen in early synapsids, the result of convergent evolution. Only a single species, A. pteroticus, is known, and it is classified in the Family Acleistorhinidae, along with Colobomycter (also from the Early Permian of Oklahoma).

References