REVIEW OF THE MIOCENE "WASTEBASKET" PECCARY GENUS PROSTHENNOPS (TAYASSUIDAE, ARTIODACTYLA): IMPLICATIONS FOR DIVERSITY ANALYSES

The genus Prosthennops was first proposed by J.W. Gidley in 1904, based a lower jaw from the Hemphillian of Sappa Creek in northwest Kansas, originally named "Dicotyles serus" by Cope (1879). Since then, Prosthennops has become the "wastebasket" name for nearly all middle and late Miocene peccary teeth that are bunodont and do not show specializations in the skull or zygomatic arches. A recent monographic review of all the North American Tayassuidae has established that most tooth fossils referred to Prosthennops do not in fact belong to that genus. The only valid species of the genus is P. serus, which is restricted to the latest Clarendonian-Hemphillian (late Miocene). Complete skulls from the early Hemphillian Cambridge l.f. of Nebraska (formerly "Prosthennops graffhami" fromt the "Kimballian") show that Prosthennops serus was a very derived peccary, with enormous flaring arched zygomatic flanges. Late Barstovian-early Clarendonian specimens formerly referred to "Prosthennops" niobrarense do not in fact belong to that genus, but are a much less derived genus without any flaring zygomatic flanges or wings that will be formally named elsewhere. Early-middle Barstovian specimens once called "Prosthennops" xiphidonticus represent an even more primitive taxon, also lacking any unusual zygomatic structures, that will be formally named yet another genus. The famous "Nebraska man" tooth, Hesperopithecus haroldcookii, mistaken for an anthropoid primate in 1922, cannot be assigned to Prosthennops either, since it is not complete enough or well enough preserved to attribute it to any of more than five peccary genera known from the late Clarendonian. Likewise, nearly all fragmentary and isolated teeth and jaws from the middle and late Miocene in collections cannot be assigned to Prosthennops or possibly any peccary genus unless they are associated with diagnostic skull material. Thus, collections records and paleontological databases that record Prosthennops from anywhere other than the latest Clarendonian-Hemphillian are in error, and they cannot be used to construct elaborate conclusions about diversity dynamics of Miocene mammals.