†Stygimys jepseni Simpson 1935
Alternative combination: Parectypodus jepseni
Synonym: Eucosmodon sparsus Simpson 1937
Full reference: G. G. Simpson. 1935. Proceedings of the United States National Museum 83
- Stygimys jepseni: Its type locality is Gidley Quarry, which is in a Torrejonian terrestrial horizon in the Fort Union Formation of Montana
- Eucosmodon sparsus: Its type locality is Upper Lebo Loc. 25, which is in a Torrejonian terrestrial horizon in the "Fort Union" (= Lebo) Formation of Montana.
Average measurements (in mm): m1 3.10 x 1.40