Nycteroleteridae is a genus of Late Permian anapsid procolophonomorphs parareptiles. Their sister taxon is Nyctiphruretidae.
Macroleter is an extinct genus of parareptile which existed in Oklahoma and Russia during the upper Permian period. It was first named by paleontologists Tverdochlebova and Ivachnenko in 1984. The type species is Macroleter poezicus from Upper Permian of Russia. Seymouria agilis (Olson, 1980) that is known from only one specimen (holotype UCMP 143 277), a nearly complete skeleton from the Chickasha Formation of Oklahoma, was reassigned by Michel Laurin and Robert R. Reisz to this genus.
Nyctiphruretus (Guardian of the Night), is an extinct genus of reptiles distantly related to turtles. The reptiles lived around about 250 million years ago and looked more like lizards than turtles. Hundreds of fossils of the species Nyctiphruretus acudens were found well preserved near the Mezen River of European Russia in all stages of growth. The dentition identified that Nyctiphruretus was a herbivore. Based on the large numbers of individuals found and the sediment that they were found in, it appears that their diet consisted of aquatic plants. Adults discovered averaged 36 cm in length with a 4.4 cm skull that was crushed but recognisable. There were two species in the genus, the type species being Nyctiphruretus acudens (Efremov, 1938) and the other species Nyctiphruretus ineptus.
Relation to rhipaeosaurids
Rhipaeosaurus and Leptoropha were originally inside the nycteroleteridae family, but now Rhipaeosaurus tricuspidens, Rihapaeosaurus talonophorus, and Leptoropha novojilovi, are in their own family: Rhipaeosauridae, a family of permian procolophonians parareptiles. This family was assigned to Cotylosauria by Tchudinov (1955), to Pareiasauria by Olson (1962), and to Pareiasauroidea by Carroll (1988).