Ustia (therapsid)

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Ustia
Temporal range: Middle Permian
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Suborder: Biarmosuchia
Genus: Ustia
Ivachnenko, 2003
Type species
Ustia atra
Ivachnenko, 2003

Ustia is an extinct genus of biarmosuchian therapsids from the Middle Permian 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, which also includes the genus Ictidorhinus from South Africa. Both are relatively small biarmosuchians. [1] Several other Russian therapsids known only from lower jaw bones have been placed in Ictidorhinidae, and the family is likely a paraphyletic assemblage representing a small body type than a true clade. [2]

They are also small mammals. They were at first misclassified as gorgonopsians. Their bones are very important in classifying other bones from other biarmosuchians therapsids. [3]

References

  1. Ivakhnenko, M. F. (2008). "Cranial morphology and evolution of Permian Dinomorpha (Eotherapsida) of eastern Europe". Paleontological Journal. 42 (9): 859–995. doi:10.1134/S0031030108090013.
  2. Sidor, C. A. (2003). "The Naris and Palate of Lycaenodon Longiceps (Therapsida: Biarmosuchia), with Comments on Their Early Evolution in the Therapsida". Journal of Paleontology. 77 (5): 977–984. doi:10.1666/0022-3360(2003)077<0977:TNAPOL>2.0.CO;2.
  3. Benoit, Julien; Manager, Paul R; Fernandez, Vincent; Rubidge, Bruce S. "The bony labyrinth of late Permian Biarmosuchia: palaeobiology and diversity in non-mammalian Therapsida". University of the Witwatersrand, Johannesburg.