Acleistorhinus

Acleistorhinus Temporal range: Early Permian, 273.6–271.6 Ma PreЄ Є O S D C P T J K Pg N ↓
Illustration of Acleistorhinus skull and full restoration.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	†Parareptilia
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

• Daly, E., 1969. "A new Procolophonoid reptile from the Early Permian of Oklahoma." Journal of Paleontology, v. 43, n. 3, p. 676-687.