A NEW GENUS OF HESPERHYINE PECCARY (MAMMALIA: ARTIODACTYLA) FROM THE LATE OLIGOCENE OF OREGON: IMPLICATIONS FOR PALEOBIOLOGICAL DATABASES

"Thinohyus" osmonti was based on a nearly complete skull and jaws (UCMP 393) found in the upper John Day beds (upper Oligocene) of Oregon, and named by W.J. Sinclair in 1905. Since its discovery, it has been transferred from one primitive peccary genus to another (Thinohyus, Bothrolabis, Perchoerus), without a careful examination of the excellent fossils. It is not referable to Thinohyus from the John Day beds, since it has a much more advanced skull, with a narrow rostrum with shallow facial vacuities, not the convex conical rostrum found in Thinohyus and more primitive peccaries. It was assigned to that genus only because its teeth are the same size and it came from the same beds, but this makes Thinohyus into a wastebasket taxon. Careful re-examination of the skull shows that it has the diagnostic plesiochoanal fossa found only in the newly recognized Subfamily Hesperhyinae, as well as other derived characters of that group. It is a relatively primitive member of that group (in the same trichotomy as Stuckyhyus siouxensis and Floridachoerus olseni) consistent with its stratigraphic position in the late Arikareean. It belongs in a new genus, which will be published elsewhere. This now makes eight genera (five of them new since 2015) and eight species (two of them new since 2015) described in this large and diverse but previously unrecognized subfamily. None of these taxa (except for Hesperhys) was recognized in any of the existing paleobiological databases (MIOMAP, PBDB), or some of them are mentioned but misassigned. Such hidden diversity, especially in poorly studied groups with lots of undescribed specimens, reveals a level of taxonomic diversity that is underestimated or misassigned in paleobiological databases, and seriously compromises their credibility.