''Ustia'' 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 ...

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 ...

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 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 ± 0. ...

of Russia. It is known from a single species, ''Ustia atra'', which was described in 2003 from an isolated lower jaw. ''Ustia'' was classified in the family

Ictidorhinidae ''Ictidorhinus'' is an extinct genus of biarmosuchian therapsids. Fossils have been found from the ''Dicynodon'' Assemblage Zone of the Beaufort Group in the Karoo Basin, South Africa and are of Late Permian age. It had a short snout and proport ...

, which also includes the genus ''

Ictidorhinus ''Ictidorhinus'' is an extinct genus of biarmosuchian therapsids. Fossils have been found from the ''Dicynodon'' Assemblage Zone of the Beaufort Group in the Karoo Basin, South Africa and are of Late Permian age. It had a short snout and proport ...

'' from South Africa. Both are relatively small biarmosuchians. Several other Russian therapsids known only from lower jaw bones have been placed in Ictidorhinidae, and the family is likely a

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

assemblage representing a small body type than a true

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

References

Biarmosuchians Prehistoric therapsid genera Guadalupian synapsids of Europe Fossil taxa described in 2003 {{paleo-therapsid-stub