The species Neoliotomus ultimus was named by Granger W. and Simpson G.G. in 1928. It has also been known as Eucosmodon ultimus (Granger & Simpson, 1928). Fossil remains were found in Clarkforkian (Paleocene) strata of Wyoming and Colorado. This species is known from a fair number of locations. It is another large multituberculate, which weighed perhaps 2 kg.
References
Jepsen (1930), "New vertebrate fossils from the Lower Eocene of the Bighorn Basin, Wyoming." Proc. Amer. Philos. Soc.69, p. 117-131, 4 pls.
Kielan-Jaworowska Z & Hurum JH (2001), "Phylogeny and Systematics of multituberculate mammals." Paleontology44, p. 389-429.