Paludicola 11(2):51-72 March 2017 © by the Rochester Institute of Vertebrate Paleontology RODENTS (MAMMALIA) FROM THE PILGRIM CREEK LOCAL FAUNA, WYOMING: A MIXED EOCENE AND OLIGOCENE ASSEMBLAGE (DUCHESNEAN TO WHITNEYAN) William W. Korth Rochester Institute of Vertebrate Paleontology, 265 Carling Road, Rochester, New York 14610 <
[email protected]> ABSTRACT Previously, only the non-eomyid rodents from the Pilgrim Creek fauna of Wyoming have been described (Sutton and Black, 1975; Korth, 1981; Korth and Emry, 2013). This fauna has been considered as Chadronian in age since its first description. Twenty-seven species of rodents are recognized here from this fauna. There is a predominance of Chadronian species (13 taxa); however, the presence of three species known elsewhere from the Duchesnean (“Leptotomus” guildayi, Metanoiamys korthi, Griphomys cf. alecer), four from the Orellan (“Prosciurus” sp., cf. relictus, Eumys elegans, “Scottimus” viduus, Protosciurus sp., cf. P. mengi), and two from the Whitneyan (Leptodontomys douglassi, Ansomys sp., cf. A. cyanotephrus,) demonstrates that the fauna is clearly mixed with elements from four different horizons. INTRODUCTION either earlier or later horizons, demonstrating the evident mixing of faunas. Over 40 years ago, Sutton and Black (1975) _________________________________________ identified 11 species of rodents from the Pilgrim Creek fauna of Wyoming (Table 1). However, TABLE 1. Previously identified rodents from the Pilgrim Creek specimens of the family Eomyidae were not local fauna, Wyoming (Sutton and Black, 1975). described or listed. The locality from which the Ischyromyidae fossils were collected is in the Teton National Forest Ischyromys cf. veterior in Jackson County, Wyoming along Pilgrim Creek Cylindrodontidae (Sutton and Black, 1975).