NEW PERSPECTIVES ON BASSARISCUS FROM THE DALLES GROUP (HEMPHILLIAN, OREGON)

Fossils from the Miocene Dalles Group of northeast Oregon provide insight into an ecosystem shaped by ongoing global cooling and expansions of grasslands. While large carnivores such as Machairodus and borophagine canids have been the focus of much recent work on these sites due to their probable role as keystone predators, reconstructing the diversity of smaller carnivorans is also crucial to understanding Dalles Group paleoecology. Among these small carnivores are procyonids, which have been previously described from but not identified below the family level at the Hemphillian Boardman and Westend Blowout localities. In order to identify the traits that are diagnostically useful for distinguishing procyonid species, we have compiled a data set of dental measurements of Miocene species from across the western United States and Canada. These data suggest that the material from Westend Blowout can be assigned to a new species of Bassariscus. This species is distinguished from others of Bassariscus by its overall large size and several features of the lower molars. Twelve specimens are recognized from Westend Blowout. This abundance and the tendency of modern Bassariscus to nest in trees may lend to support to early interpretations of this locality as representing a woodland habitat.