''Niaftasuchus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...

s. Its type and only named species is ''Niaftasuchus zekkeli''. ''Niaftasuchus'' had distinctive dentition. It has been interpreted as one of the earliest known herbivorous therapsids. It lived during 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 ± 0. ...

epoch of the

Permian The Permian ( ) is a geologic period and 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 period of the Paleoz ...

in what is now

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

, and inhabited an environment alongside some of the last non-therapsid synapsids, such as the caseasaur ''

Ennatosaurus ''Ennatosaurus'' is an extinct genus of caseid synapsid that lived during the Middle Permian (late Roadian - early Wordian) in northern European Russia. The genus is only represented by its type species, ''Ennatosaurus tecton'', which was named i ...

'' and the varanopid ''

Mesenosaurus ''Mesenosaurus'' is an extinct genus of amniote. It belongs to the family Varanopidae. This genus includes two species: the type species ''Mesenosaurus romeri'' from the middle Permian (upper Kazanian) Mezen River Basin of northern Russia, and ' ...

''. ''Niaftasuchus'' is one of several enigmatic early therapsids from Russia that may be based on juvenile material. Its phylogenetic affinities are controversial; it has been classified as a biarmosuchian, dinocephalian, or anomodont, and it has also been suggested to belong to a lineage of its own.

Description

''Niaftasuchus'' has a distinctive dentition composed of large, procumbent, leaf-shaped teeth. There are three pairs of incisors, but the canines are not particularly distinct from the other maxillary teeth. There are a few palatal teeth. Like biarmosuchians, ''Niaftasuchus'' has exceptionally large eye sockets, though this may be a juvenile character. The skull is low and broad. The known specimens of ''Niaftasuchus'' are very small; the holotype skull is only long. It has been interpreted as being based on probable juvenile material.

History of study

The holotype specimen of ''Niaftasuchus zekkeli'', an incomplete skull without the mandible, was collected near the

Pyoza The Pyoza (russian: Пёза) is a river in Mezensky District of Arkhangelsk Oblast in Russia. It is a right tributary of the Mezen. It is long, and the area of its basin . The main tributaries of the Pyoza are the Tsema (left), Varchushka (r ...

river in

Arkhangelsk Oblast Arkhangelsk Oblast (russian: Арха́нгельская о́бласть, ''Arkhangelskaya oblast'') is a federal subjects of Russia, federal subject of Russia (an oblast). It includes the Arctic Ocean, Arctic archipelagos of Franz Josef Land ...

, near Nyafta (russian: Няфта). It was named in 1990 by M. F. Ivakhnenko, with the name referring to the place where it was found and honoring the geologist I. D. Zekkel. Ivakhnenko initially interpreted it as a

tapinocephalian The Tapinocephalia are one of the major groups of dinocephalian therapsids and the major herbivorous group. Tapinocephalia has been found to consist of three clades: Styracocephalidae, Titanosuchidae, and the very successful Tapinocephalidae. No ...

, but subsequently proposed a monotypic order, Niaftasuchida, for it. In 2000, Battail and Surkov argued it was a biarmosuchian. In 2001, Ivakhnenko suggested it was an anomodont, but in 2003 returned to regarding it as a dinocephalian on the basis of new material.

Classification

The classification of ''Niaftasuchus'' is considered problematic. It is assigned to a family of its own, Niaftasuchidae. Ivakhnenko, who first described ''Niaftasuchus'', regards it as a basal

dinocephalian Dinocephalians (terrible heads) are a clade of large-bodied early therapsids that flourished in the Early and Middle Permian between 279.5 and 260 million years ago (Ma), but became extinct during the Capitanian mass extinction event. Dinocepha ...

, whereas Battail and Surkov classified ''Niaftasuchus'' in

Biarmosuchia Biarmosuchians are an extinct clade of non-mammalian synapsids from the Permian. They are the most basal group of the therapsids. All of them were moderately-sized, lightly-built carnivores, intermediate in form between basal sphenacodont "pelyc ...

. It is also possible that it belongs to neither lineage, and forms a distinctive therapsid group of its own. There is only one named species, ''Niaftasuchus zekkeli'', but a specimen that may represent a second species is known. It differs from the type species in having a straight tooth row without enlarged maxillary teeth.

Paleobiology

''Niaftasuchus'' is interpreted as an herbivore, with its teeth adapted primarily for tearing off soft plant parts. Based on possible coprolites found in the mouth of a juvenile specimen, Ivakhnenko suggested that juvenile ''Niaftasuchus'' would ingest coprolites to develop their

gut microbiota Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut m ...

, as in many modern herbivores.

References

Bibliography