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Rodents (Mammalia) from Fitterer Ranch, Brule Formation (Oligocene), North Dakota book cover

Rodents (Mammalia) from Fitterer Ranch, Brule Formation (Oligocene), North Dakota

Eighteen rodent species are recognized from the Fitterer Ranch fauna of North Dakota based on more than a thousand collected specimens. Of the species recognized, four are new: the prosciurine aplodontids Prosciurus hogansoni and Altasciurus leonardi, the heliscomyid Heliscomys borealis and the cricetid Eumys lammersi. A previously described castorid from this fauna, Oligotheriomys primus Korth, 1998, is considered a synonym of “Eutypomys” magnus Wood, 1937, on the basis of the recovery of lower dentitions, but is retained in the genus Oligotheriomys. A single specimen is questionably referred to Microparamys, a genus elsewhere limited to the earlier Eocene (Clarkforkian-Chadronian Land Mammal Ages). The rodent fauna appears to be a combination of predominantly Orellan and Whitneyan species (early Oligocene), suggesting that the section might transcend the Orellan-Whitneyan boundary. However, the rodent fauna does not alter significantly from the lowest to the highest horizons.

Publication Date: March 11, 2019

Availability: Paperback, Electronically