Dakotamys is a genus of extinct mammal that lived during the Upper Cretaceous. It shared the world with dinosaurs. This small creature was a member of the also extinct order Multituberculata within the suborder Cimolodonta and was a member of the Paracimexomys group.
The genus Dakotamys ("Dakota mouse") was named by Eaton J.G. in 1995. Dakota refers to the Dakota Formation. It's a geological term rather than a geographical one. "Paracimexomys and Dakotamys... resemble the Eobaataridae in the structure of the upper and lower molars, with cusps showing a tendency to coalesce, and with ornamentation of grooves and ribs on the molars," (Kielan-Jaworowska & Hurum, 2001, p.403).
Species: Dakotamys malcomi Eaton JG, 1995
Place: Cenomanian (Upper Cretaceous)-age strata of the Dakota Formation, Utah. This species would have weighed perhaps 25 g. The type specimen is in Oklahoma. Some material from Utah has subsequently been reassigned to a different genus, Cedaromys (Eaton & Cifelli 2001.). "Dakotamys" Tedrow & Korth, 1997 was a description of fossil rodents, which were subsequently renamed Dakotallomys. These two species, D. lillegraveni and D. pelycomyoides, really are from the south of the Dakota Formation, but are obviously not multituberculates.