''Nyctiphruretus'' (meaning "Guardian of the Night") 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 ...

nyctiphruretid Nyctiphruretidae is an extinct family of hallucicranian parareptiles known from the late Early to the late Middle Permian of European Russia and south-central United States. Nyctiphruretidae was named by Efremov in 1938. The type genus is ''Nyct ...

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

Guadalupian 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 ± ...

series (middle

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...

) of European Russia. Many

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s of the type species, ''N. acudens'', were found well preserved near 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 ...

of European Russia in various stages of growth. The dentition identified that ''Nyctiphruretus'' is 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. ''Nyctiphruretus'' was first named by Efremov in 1938 and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

is ''Nyctiphruretus acudens''. In 2002, a second species was named by V. V. Bulanov. ''N. optabilis'' is known from a single

jaw The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth and serv ...

, also from Russia, Eastern Europe. Lee (1997) named the order

Nyctiphruretia Nyctiphruretidae is an extinct family of hallucicranian parareptiles known from the late Early to the late Middle Permian of European Russia and south-central United States. Nyctiphruretidae was named by Efremov in 1938. The type genus is '' ...

and the family Nyctiphruretidae, to include ''Nyctiphruretus''. While the family was defined to be

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

, the order was defined to include both nyctiphruretids and

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)'' ...

s. However, recent

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analyses suggest that

s are more closely related to the

Pareiasauria Pareiasaurs (meaning "cheek lizards") are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permian ...

instead, thus making ''Nyctiphruretus'' the only genus of its order. In 2014, MacDougall & Reisz described and named a second genus of Nyctiphruretidae, ''

Abyssomedon ''Abyssomedon'' (meaning "Guardian of the Abyss") is an extinct genus of a nyctiphruretid parareptile known from Early Permian (Artinskian age) fissure fills at Richards Spur in Comanche County, Oklahoma, south-central United States. It contain ...

'', from the middle

Leonardian In the geologic timescale, the Kungurian is an age or stage of the Permian. It is the latest or upper of four subdivisions of the Cisuralian Epoch or Series. The Kungurian lasted between and million years ago (Ma). It was preceded by the Artin ...

stage of the late Early Permian of

Comanche County, Oklahoma Comanche County is a county located in the U.S. state of Oklahoma. As of the 2010 census, the population was 124,098, making it the fourth-most populous county in Oklahoma. Its county seat is Lawton. The county was created in 1901 as part of ...

, south-central United States. It contains a single species, ''A. williamsi'', which represents the first nyctiphruretid known from North America, and the oldest species of the family.

References

{{Taxonbar, from=Q2425306 Procolophonomorphs Permian reptiles of Europe Prehistoric reptile genera