A systematic revision of Daphoenus and some allied genera [U.S.]

A revision is made of the genus Daphoenus and a new, very small species described. Hatcher's genera, Proamphicyon and Protemnocyon are redescribed from additional specimens in the U. S. National Museum. Daphoenus dodgei, known only from lower jaws, is referred to a new genus, Daphoenocyon, based on two specimens from the Lower Brule, both complete skulls with articulated lower jaws, one associated with a partial skeleton. Daphoenus and the related genera described in the paper, are shown to be distinct from the typical Canidae represented by Pseudocynodictis, Nothocyon and the John Day canids. It is suggested that notwithstanding the great amount of parallelism and convergence between the two groups the differences in the auditory region, proportions of the skull and details of the dentition, as well as the general evolutionary trends in the two groups, are sufficient to warrant placing them in separate families. The family Daphoenidae, while remaining conservative in limb structure and dentition, evolved more rapidly in size, culminating in the gigantic bear dogs of the Arikarean. The more typical Canidae attained the characteristic canid specializations very early and after a minor radiation in the John Day, provided the direct ancestry through Tomarctus of all of the living canids.