FOSSIL DEER (CERVIDAE) FROM THE PLEISTOCENE SNOWMASTODON SITE, PITKIN COUNTY, COLORADO WITH COMMENTS ON NORTH AMERICAN TAXA

A nearly complete articulated skeleton of a fossil deer from the Snowmastodon Site in Pitkin County, Colorado, late Pleistocene (~70,000 years ago), is one of the most complete specimens of fossil Cervidae from North America. This specimen has several unique characteristics that contrast with modern Odocoileus including relatively longer and more slender metacarpals and metatarsals, larger size (about 10%), and a dentary with an enlarged p4 with the crown height greater than the height of any molars. The specimen represents a male individual of approximately 2.5 years of age with large antlers that have a basic morphology similar to that of O. hemionus, the mule deer. We consider Navahoceros and Sangamona to be valid late Pleistocene genera, recognized respectively by the robust, short metapodials in the former, and the long, slender metapodials in the latter compared to both modern O. hemionus and O. virginianus and other fossil taxa of Odocoileus. Both of these genera are larger than the living species of North American Odocoileus. The fourth premolar enlargement in the Snowmastodon skeleton is unique but is found in a specimen described by Frick in 1937 from the Pleistocene of California and assigned to a new species, O. cascensis. The specimen from Snowmass has limbs similar to Sangamona, antler morphology similar to O.hemionus, premolar morphology similar to that of a specimen from California resulting in a unique combination of characters. The relationships of North American cervids will be reviewed. An additional faun dentary, toe and pelvic fragment from the Snowmastadon Site are assigned to Odocoileus sp. indet.