Buginbaatar
Scientific classification
Kingdom: Animalia
Therapsida
Class: Mammalia
Order: Multituberculata
Family: Cimolomyidae
Genus: Buginbaatar
Species
  B. transaltaiensis

Ref.

Buginbaatar is a mammal genus from the Upper Cretaceous of Mongolia. It was a member of the extinct order of Multituberculata. It lived towards the end of 'the age of the dinosaurs'.
For those of a technical inclination, it's within the Suborder of Cimolodonta, and the family Cimolomyidae.

Genus: Buginbaatar Kielan-Jaworowska Z & Sochava AV, 1969

Species: Buginbaatar clarki Kielan-Jaworowska Z & Sochava AV, 1969
Place: Bügiyn Tsav
Country: Mongolia
Age: Upper Cretaceous
Remarks: The only known Upper Cretaceous Mongolian multi not to belong to Djadochtatherioidea. Remains are incomplete and the assignment of B. to the Cimolomyidae is tentative, (Kielan-Jaworowska & Hurum 2001, p.408).
Reference: Kielan-Jaworowska & Sochava (1969), The first multituberculate from the uppermost Cretaceous of the Gobi Desert (Mongolia). Acta Palaeontologica Polonica, 14, p.355-371.

Page reference: 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; 'basal' Cimolodonta, Cimolomyidae, Boffiidae and Kogaionidae, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)