Two New Cenozoic Microtine Rodents

Abstract

Further washing of matrix from the Saw Rock Canyon local fauna locality in southwestern Kansas has produced numerous parts of a vole previously reported as Cosomys . Sufficient material has been found to show that the vole is distinct from Cosomys . It is here reported as a new species of the Pliocene genus Ogmodontomys . A lower jaw of a small vole from the early Pleistocene Sand Draw local fauna of Nebraska is described as a new genus and species. Cosomys primus Wilson, Hibbard, 1949. Contrib. Mus. Paleo., Univ. Mich., vol. 7, no. 5, p. 103, fig. 2C–E. Fig. 1 (A-F) Ogmodontomys sawrockensis sp. nov. (A and B) Occlusal view of RM1-M3, and lateral view of right ramus, paratype UMMP No. 29715. (C) Ventral view of palate with RM1, holotype, UMMP No. 28166. All × 6. (D, E and F) Occlusal, lingual and anterior views of LM3, No. 33654a. × 8. (G) Ventral view of palate with RM1 and M2, and LM1-M3, of Ogmodontomys poaphagus. × 6. Drawing by Michael O. Woodburne. Fig. 2 (A and B) Occlusal view of RM1, and lateral view of right ramus of Nebraskomys mcgrewi gen. and sp. nov.; holotype UMMP No. 25610. × 8. (C-I) Ogmodontomys sawrockensis sp. nov. (G and D) Occlusal view of RM1 and M2 and lateral view of right ramus, UMMP No. 31013. × 6. (E, F and G) Occlusal, lingual and anterior views of LM3, UMMP No. 33654b. × 8. (H and I) Labial views of RM1, UMMP, No. 33653a-b. × 8. Drawing by Michael O. Woodburne. Cosomys primus Wilson, Hibbard, 1953. Pap. Mich. Acad. Sci. Arts and Letters, vol. 38 (1952), p. 406. Holotype .—No. …