North American amphicyonid carnivorans are important members of the mid-Cenozoic terrestrial carnivore community during the late Eocene to late Miocene (Duchesnean to Clarendonian). Species range in size from < 5 kg to > 200 kg. Among the smallest and rarest amphicyonids are Oligocene species of Paradaphoenus Wortman and Matthew, found at a few localities in the Great Plains and the Pacific Northwest. Paradaphoenus is known from only 10 individuals placed in 3 species (P. minimus; P. tooheyi, n. sp.; P. cuspigerus), representing a single lineage ranging from the Orellan to Arikareean. The existence of three skulls, one with associated mandibles, allows the identification of diagnostic basicranial and dental traits that place the genus in the Amphicyonidae. Basicranial anatomy, including a rudimentary ectotympanic auditory bulla, distinguishes the genus from more abundant small contemporary canids, such as Hesperocyon. The species of Paradaphoenus most likely adopted ecological roles similar to the smaller living foxes.