Acleistorhinus (ah-kles-toe-RYE-nuss) 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, a 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).
Acleistorhinus (ah-kles-toe-RYE-nuss) 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, a 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).
==Etymology== Acleistorhinus was first discovered and named by Eleanor Daly in 1969 in the Hennessey Formation of South Grandfield, Tillman county, Oklahoma. The name Acleistorhinus combines Greek rhin (ῥῑ́ν), meaning "nose," and akleistos, Greek for "unclosed."
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).