Two species are known, Reiszia gubini and R. tippula, both found in middle Permian sediments in the Mezen River Basin of European Russia. R. gubini is known from a partial skull and mandible, while R. tippula is known only from a mandible.[1][2]
^M. F. Ivakhnenko, 2000. The Nikkasauridae-Problematic Primitive Therapsids from the Late Permian of the Mezen Localities. Paleontol. J. 34(Suppl. 2), 179–186.
^M. F. Ivakhnenko. 2008. Podklass Theromorpha. In M. F. Ivakhnenko and E. N. Kurochkin (eds.), Iskopaemye pozvonotchnye Rossii i sopredel'nykh stran: Iskopaemye reptilii i ptitsy, Tchast' 1 [Fossil vertebrates of Russia and adjacent countries: Fossil reptiles and birds, Part 1], GEOS, Moscow 101-183
Kemp, Thomas Stainforth (2005). The Origin and Evolution of Mammals. ISBN0-19-850760-7.
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