Kryptobaatar
Scientific classification
Kingdom: Animalia
Therapsida
Class: Mammalia
Order: Multituberculata
Family: Djadochtatheriidae
Genus: Kryptobaatar
Species
  K. dashzevegi
  K. gobiensis
  K. mandahuensis
  K. saichanensis

Ref.

Kryptobaatar is a mammal genus known from the Upper Cretaceous of Central Asia. It lived alongside some of the 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: Kryptobaatar Kielan-Jaworowska Z, 1970
'hidden hero'
Aka: Gobiaatar, Gobibaatar ('Gobi hero') Kielan-Jaworowska Z, 1970; Tugrigbaatar Kielan-Jaworowska Z & Dashzeveg D, 1978
Remarks: "Gobibaatar has page priority but was selected as the junior synonym by Kielan-Jaworowska in 1980," (McKenna & Bell, 1997).

Species: Kryptobaatar dashzevegi Kielan-Jaworowska Z, 1970
Place: Djadokhta Formation, Ukhaa Tolgod and Tögrög Shiree
Country: Mongolia
Age: ?lower Campanian, Upper Cretaceous
Remarks: The skull has a length of perhaps 3cm. I’m no expert, but the front teeth look impressively sharp and not much like those of a strict vegetarian.
Reference: Kielan-Jaworowska (1970), New Upper Cretaceous multituberculate genera from Bayn Dzak, Gobi Desert. In: Kielan-Jaworowska (ed.), Results of the Polish-Mongolian Palaeontological Expeditions, pt. II. Palaeontologica Polonica 21, p.35-49.

Species: Kryptobaatar gobiensis
Aka: Gobibaatar parvus Kielan-Jaworowska Z, 1970
Place:
Country:
Age: Upper Cretaceous
Remarks: This is wild speculation, but I suspect this is from the Gobi, Mongolia.
Reference: Kielan-Jaworowska (1970), New Upper Cretaceous multituberculate genera from Bayn Dzak, Gobi Desert. In: Kielan-Jaworowska (ed.), Results of the Polish-Mongolian Palaeontological Expeditions, pt. II. Palaeontologica Polonica 21, p.35-49.

Species: Kryptobaatar mandahuensis Smith T, Guo D-Y & Sun Y, 2001
Place: Bayan Mandahu red beds, Inner Mongloia
Country: China
Age: Campanian, Upper Cretaceous
Remarks: Based on several well preserved skulls. This location is about the same age as the Djadokhta Formation of Mongolia).
Reference: Smith et al (2001), A new species of Kryptobaatar (Multituberculata): the first Late Cretaceous mammal from Inner Mongolia (P. R. China). Bulletin de l’Inst. royal des Sci. nat. de Belgique, Sci. de la Terre Supplement 71, p.29-50.

Species: Kryptobaatar saichanensis (Kielan-Jaworowska Z & Dashzeveg D, 1978)
Aka: Tugrigbaatar saichanensis Kielan-Jaworowska Z & Dashzeveg D, 1978
Place:
Country: Mongolia
Age: Upper Cretaceous
Remarks:
Reference:

Page references: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.
McKenna MC & Bell SK, (1997), Classification of Mammals Above the Species Level. Columbia University Press.

(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)