The mesocarnivorous procyonine genera Bassariscus and Probassariscus first appear in the early Barstovian, when they are represented by four species. Bassariscus antiquus is known from the Olcott Formation of Nebraska, B. cf. parvus from the Skull Ridge Member of the Tesuque Formation of New Mexico, and B. minimus, sp. nov., from the Olcott Formation and Observation Quarry in Nebraska. Probassariscus is restricted to the single species P. matthewi from the Virgin Valley Formation of Nevada, Observation Quarry of Nebraska, and possibly the Flemming Formation of Texas. The subfamily Procyoninae is divided into two tribes, Potosini and Procyonini. The procyonin Probassariscus is more closely related to Procyon and Nasua than to Bassariscus. Based on dental characteristics, Bassariscus is the most primitive genus of the Procyonini.