Djadochtatherium
Scientific classification
Kingdom: Animalia
Therapsida
Class: Mammalia
Order: Multituberculata
Family: Djadochtatheriidae
Genus: Djadochtatherium
Species
  D. matthewi

Ref.

Djadochtatherium is a mammal genus that lived in Mongolia during the Upper Cretaceous. It coexisted with some of the late dinosaurs. This animal was a member of the extinct order of Multituberculata.
For those of a technical disposition, it's within the suborder of Cimolodonta, and a member of the family Djadochtatheriidae.

Genus: Djadochtatherium Simpson GG, 1925
'Djadokhta beast'

Species: Djadochtatherium matthewi Simpson GG, 1925
Aka: Catopsalis matthewi (Simpson GG, 1925)
Place: Djadokhta Formation & Goyot Formation
Country: Mongolia
Age: Campanian, Upper Cretaceous
Remarks: This was a relatively large multituberculate, with a skull length of about 4.5cm. It was originally diagnosed as a species within the North American genus of Catopsalis.
Reference: Simpson (1925), A Mesozoic mammal skull from Mongolia. American Museum Novitates 201, p.1-11.

Page references: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.

(This information has been derived from [1] MESOZOIC MAMMALS; Djadochtatherioidea, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)