Eucosmodon
Scientific classification

Kingdom: Animalia
Therapsida
Class: Mammalia
Order: Multituberculata
Family: Eucosmodontidae
Genus: Eucosmodon
Species
  E. americanus
  E. molestus
  E. primus

Ref.

Eucosmodon is a mammal genus from the Paleocene of North America. It was a member of the extinct order of Multituberculata within the Suborder of Cimolodonta, and the family Eucosmodontidae.

Genus: Eucosmodon Matthew WD & Granger W, 1921
Aka: Neoplagiaulax (partly)
Remarks: Remains are restricted to teeth.

Species: Eucosmodon americanus (Cope ED, 1885) Matthew WD & Granger W, 1921
Aka: Neoplagiaulax americanus Cope, 1885
Place: San Juan Basin, New Mexico
Country: USA
Age: Puercan, Paleocene
Remarks: Some, but not all material has been rediagnosed as E. primus. This animal, which probably weighed something like 750g, has been cited as a possible descendant of that species.
Reference: Matthew & Granger (1921), New genera of Paleocene mammals. American Museum Novitates, 13, p.1-7.

Species: Eucosmodon molestus (Cope ED, 1886) Granger W & Simpson GG, 1929
Aka: Neoplagiaulax molestus Cope, 1886
Place: San Juan Basin, New Mexico
Country: USA
Age: Torrejonian, Paleocene
Remarks: Has been cited as a possible descendant of E. americanus.
Reference:

Species: Eucosmodon primus either Granger W & Simpson GG, 1929 or Sloan RE, 1981 (I'm not sure!)
Place: Nacimiento Formation, San Juan Basin, New Mexico
Country: USA
Age: Puercan, Paleocene
Remarks: Based on fossils originally ascribed to E. americanus.
Reference: Fox (1971), Canadian J of Earth Sci 8: 916.

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; Eucosmodontidae, Microcosmodontidae and Taeniolabidoidea, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)