Phthinosuchia

Phthinosuchia Temporal range: Middle Permian, 270 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Life restoration of Phthinosuchus discors
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Suborder:	†Dinocephalia (?)
Clade:	†Anteosauria (?)
Infraorder:	†Phthinosuchia Romer, 1961
Subgroups
See text.

Phthinosuchia is an extinct group of therapsids including two poorly known species, Phthinosuchus discors and Phthinosaurus borrisiaki, from the Middle Permian of Russia. Phthinthosuchus is known a partial crushed skull and Phthinosaurus is known from an isolated lower jaw.[1] The two species have traditionally been grouped together based on their shared primitive characteristics, but more recent studies have proposed that they are more distantly related. Phthinosuchus is either a carnivorous gorgonopsian relative[2] or an anteosaurian dinocephalian while Phthinosaurus is either a herbivorous rhopalodont dinocephalian[2][3] or a therocephalian.[4]

Phthinosuchia was named by American paleontologist Everett C. Olson in 1961, who considered it the most primitive infraorder within Therapsida. A year later Olson named the new infraorder Eotheriodontia and reclassified Phthinosuchia as a subgroup of eotheriodonts, along with the families Biarmosuchidae and Brithopodidae. Each species has been placed in its own family; Phthinosuchidae was named by Soviet paleontologist Ivan Yefremov in 1954 for both Phthinthosuchus and Phthinosaurus, while Phthinosauridae was named by Leonid Tatarinov in 1974 for Phthinosaurus alone.[5]

References

1. Kazlev, A.; White, T. (14 November 2009). "Therapsida: Phthinosuchidae". Palaeos.com. Retrieved 25 November 2012.
2. Kemp, T.S. (2011). "The origin and radiation of therapsids". In Chinsamy-Turan, A. (ed.). Forerunners of Mammals. Bloomington: Indiana University Press. pp. 3–30. ISBN 978-0-253-35697-0.
3. 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. S2CID 85114195.
4. Battail, B. (2000). "A comparison of Late Permian Gondwanan and Laurasian amniote faunas". Journal of African Earth Sciences. 31 (1): 165–174. doi:10.1016/s0899-5362(00)00081-6.
5. Battail, B.; Surkov, M.V. (2003). "Mammal-like reptiles from Russia". In Benton, M.J.; Shishkin, M.A.; Unwin, D.M. (eds.). The Age of Dinosaurs in Russia and Mongolia. Cambridge: Cambridge University Press. pp. 86–119. ISBN 9780521545822.