Mnemeiosaurus

Mnemeiosaurus jubilaei or Deuterosaurus jubilaei is an extinct species of dinocephalian therapsids. It was originally named as representing a distinct genus, Mnemeiosaurus ("remembrance lizard"), by Franz Nopcsa in 1928, which some authors, such as Boonstra and Tchudinov, have agreed with, whereas some authors, such as Efremov and Ivakhnenko, regard it as a species of Deuterosaurus. Two skulls, the holotype PIN 1954/2 and a referred specimen, PIN 2629/1, are known.

Mnemeiosaurus Temporal range: Middle Permian
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Suborder:	†Dinocephalia
Family:	†Brithopodidae
Genus:	†Mnemeiosaurus Nopcsa, 1928
Species:	†M. jubilaei
Binomial name
†Mnemeiosaurus jubilaei Nopcsa, 1928

Taxonomic history

The skull that would become the type specimen of Mnemeiosaurus jubilaei was described by Harry Govier Seeley in 1894 as a specimen of Deuterosaurus. In 1925, during the 200 years jubilee of the Russian Academy of Science, Franz Nopcsa re-examined the skull and concluded that it represented a distinct taxon, which in 1928 he named Mnemeiosaurus jubilaei, the genus name being derived from Greek μνημεῖον "token, remembrance" in reference to the festivities during which he studied the specimen. He considered M. jubilaei to be a tapinocephalian. Nopcsa considered a skull fragment, consisting only of the palate, that Seeley had included in Deuterosaurus to represent yet another distinct taxon, which he named Uraniskosaurus watsoni, from Greek οὐρανίσκος "palate" and in honor of M. D. S. Watson. He considered it to have gorgonopsian affinities. However, in 1954, Ivan Efremov concluded that both Mnemeiosaurus and Uraniscosaurus were based on the same skull. He considered both names to be synonyms of Deuterosaurus. In 1965, Lieuwe Dirk Boonstra considered Efremov's interpretation to be erroneous and regarded Deuterosaurus as an anteosaur, while, like Nopcsa, he considered Mnemeiosaurus to be a tapinocephalian. In 1983, Tchudinov also retained Mnemeiosaurus and Deuterosaurus as distinct taxa. He classified Mnemeiosaurus as a "brithopodid", whereas he classified Deuterosaurus in its own family, Deuterosauridae.

See also

• List of therapsids

References

Works cited

• Boonstra, L. D. (1965). "The Russian dinocephalian Deuterosaurus". Annals of the South African Museum. 48 (12): 233–236.
• Efremov, I. A. (1954). "Фауна наземных позвоночных в пермских медистых песчаниках западного приуралья". Труды палеонтогического института (in Russian).
• Ivakhnenko, M. F. (2008). "Подкласс Theromorpha" [Subclass Theromorpha]. In Ivakhnenko, M. F.; Kurochkin, E. N. (eds.). Ископаемые позвоночные России и сопредельных стран: Ископаемые рептилии и птицы: Часть 1 [Fossil vertebrates of Russia and adjacent countries: Fossil reptiles and birds: Part 1] (in Russian). pp. 101–183.
• Nopcsa, Franz (1928). "Palaeontological notes on reptiles". Geologica Hungarica Series Palaeontologica. 1: 3–84.
• Seeley, H. G. (1894). "Researches on the structure, organization, and classification of the fossil Reptilia. VIII. Further evidences of the skeleton in Deuterosaurus and Rhopalodon, from the Permian rocks of Russia". Philosophical Transactions of the Royal Society of London B. 185: 663–717. JSTOR 91782.
• Tchudinov, P. K. (1983). "Ранние терапсиды" [Early Therapsids]. Труды палеонтогического института (in Russian). 202.

• The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive