''Nycteroleter'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

nycteroleterid 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)'' ...

parareptile Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near th ...

known from the

Middle Permian The Guadalupian is the second and middle series/ epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± ...

of European Russia. Fossils were first found in the

Mezen River The Mezen (russian: Мезень) is a river in Udorsky District of the Komi Republic and in Leshukonsky and Mezensky Districts of Arkhangelsk Oblast in Russia. Its mouth is located in the Mezen Bay of the White Sea. Mezen is one of the biggest r ...

, near to

Arkhangelsk Arkhangelsk (, ; rus, Арха́нгельск, p=ɐrˈxanɡʲɪlʲsk), also known in English as Archangel and Archangelsk, is a city and the administrative center of Arkhangelsk Oblast, Russia. It lies on both banks of the Northern Dvina near ...

. Within the

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)''. Th ...

, it is considered most closely related to '' Emeroleter.'' However, its legs were shorter than those of ''Emeroleter'' and its skull was flatter. ''Nycteroleter'' was insectivorous, and may have been nocturnal. It was a small animal, less than a metre long.

Classification

''Nycteroleter'' is classified as a primitive

procolophonia The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria (later renamed Captorhinida Carroll 1988) but are ...

n, related to the Pareisauridae. It is not certain whether the nycteroleterids formed a monophyletic or

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

group, as '' Rhipaeosaurus'' seems to be more similar to pareisaurids than to other nycteroleterids. Previously, it was uncertain whether nycteroleterids were

parareptiles Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids ( reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near t ...

or reptile-like amphibians.

References

Permian reptiles of Europe Pareiasauromorphs Fossil taxa described in 1938 Prehistoric reptile genera {{paleo-reptile-stub