Rhipaeosaurus is an extinct genus of nycteroleterid parareptile known from an articulated skeleton from the mid Middle Permian of European Russia. It contained a single species, Rhipaeosaurus tricuspidens. A bayesian analysis suggests that it is more closely related to pareiasaurs than to the other nycteroleterids, due to skull and tooth features. For this reason, "Nycteroleteridae" may be a grade rather than a clade, unless redefined to exclude Rhipaeosaurus.
Rhipaeosaurus is an extinct genus of nycteroleterid parareptile known from an articulated skeleton from the mid Middle Permian of European Russia. It contained a single species, Rhipaeosaurus tricuspidens. A bayesian analysis suggests that it is more closely related to pareiasaurs than to the other nycteroleterids, due to skull and tooth features. For this reason, "Nycteroleteridae" may be a grade rather than a clade, unless redefined to exclude Rhipaeosaurus.
== Description == Rhipaeosaurus is around a meter long, larger than any other "nycteroleterids" and closer in size to later pareiasaurs. Postcranial remains were similar to Macroleter, though the limbs were more robust and the ankle bones were unfused. The teeth were flattened and tricuspid (possessing three cusps), seemingly intermediate in form between the one- or two-cusped teeth of earlier nycteroleterids and the multi-cusped teeth of pareiasaurs. Many components of the partial skull and skeleton (which was originally fairly complete) had been lost or degraded between 1940 and 2012, obscuring most aspects of its anatomy.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).