Nycteroleteridae

Nycteroleteridae is a family of procolophonian parareptilians (extinct early reptiles) from the Middle to Late Permian of Russia and North America. They are sometimes classified as a sister group to pareiasaurids (but see Classification). The group includes the genera Macroleter, Bashkyroleter, "Bashkyroleter" mesensis, Nycteroleter, Emeroleter, and probably Rhipaeosaurus. They were carnivorous, and occasionally ate insects. The group was most common in European Russia, with only a few fossils in North America. One fossil has also been found in Africa, but this is the only one from Gondwana.

== Classification == Nycteroleteridae is sometimes considered a sister group to the Pareiasauridae, but Bayesian inference suggests that it was in fact paraphyletic, with Rhipaeosaurus a basal member of the Pareiasauridae and other members of the Nycteroleteridae as outgroups. This is supported by the appearance of Rhipaeosaurus' skull and teeth - it had tricuspid teeth and multiple horns on the skull, resembling a pareiasaur but smaller and with a longer tail. For this reason it is often seen as intermediate between more primitive nycteroleterids and more advanced pareiasaurids such as Scutosaurus.