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Russian Journal of Theriology

A new genus of the tegotheriid docodonts (Docodonta, Tegotheriidae) from the Early Cretaceous of West Siberia // Russian J. Theriol. Vol.1 (for 2002). No.2: 7581 [in English].

Sibirotherium rossicus gen. et sp. nov. from the Early Cretaceous Ilek Svita in West Siberia (Shestakovo locality) is described based on lower jaw fragments. The lower molars exhibit the typical docodont pattern with the main cusp a connected by transverse crests to the lingual cusps c and g . By absence of crests bg and cd , and presence of crests be and eg , as well as by the development of an enlarged anterior basin, Sibirotherium gen. nov. is similar to Tegotherium from the Late Jurassic of Mongolia. These two genera are united in the endemic Asian family Tegotheriidae. The new genus is plesiomorphic in retaining well developed crest df , and it is more derived than Tegotherium in partial reduction of the crest eg . The morphological diversity of the tegotheriids suggests a significant differentiation of the Late Jurassic Early Cretaceous docodonts in Asia . Key words : Sibirotherium rossicus gen. et sp. nov., Tegotheriidae, Docodonta, Early Cretaceous, West Siberia.