A new genus of otter from the Pliocene of the northern Great Basin Province

Systematic collecting over a number of years in the Thousand Creek beds of northwestern Nevada has furnished one of the largest and best-known mammalian faunas from the Pliocene of the Great Basin province. Among the carnivores recorded in the assemblage are several mustelid forms. To this list is now added a representative of the Lutrinre, based on material secured by the California Institute of Technology in the Thousand Creek beds during the field season of 1929. The discovery of this material has led to the recognition of a related type in the Rattlesnake Pliocene fauna of the John Day region, Oregon. Thus, added information becomes available concerning the relationships of the Thousand Creek and Rattlesnake faunas. Mustelid types are not uncommon in later Tertiary faunas of western America, but it is noteworthy that forms having a direct ancestral relationship to the modern otters are wholly lacking in the record or are but doubtfully established. The present material from the middle and earlier Pliocene aids in extending backward the history of the lutrine division of the Mustelidre, at least to this stage in the Tertiary