A NEW GENUS AND SPECIES OF LATE MIOCENE PECCARY WITH BIZARRE FLARING CHEEKBONES

There are several late Miocene peccaries with unusual flaring cheekbones. They include Macrogenis crassigenis, named by W.D. Matthew in 1924 for a skull with broad flaring triangular cheekbones, or "zygomatic wings", and Skinneryhus shermerorum, whose cheekbones stick out as vertical “fins” on the side of its face. Some newly documented peccary fossils have skulls that were once misidentified as Macrogenis, but they about 25% larger, with an even longer rostrum and longer post-canine diastema. All of the specimens are from the middle Clarendonian Merritt Dam Member, Ash Hollow Formation (late Miocene, 10-11.5 Ma) of north-central Nebraska, primarily from the Frick Leptarctus Quarry and Trailside Kat Quarry. These skulls have broad flaring zygomatic arches that stick out laterally from the side of skull and form a point with a twist at the base. This condition is unlike the very different flaring cheekbones of Macrogenis crassigenis, Skinnerhyus shermerorum, or any other peccary known so far. Based on the condition of the canine tusks, both male and female skulls can be identified, and this might explain some of the variability in the shape of the flaring zygomatic wings. These fossils represent a new genus and species to be named and described elsewhere. The broad flare of the zygomatic arch in several groups of peccaries parallels the condition found in some entelodonts, as well as suids like the warthogs. The flaring zygomatic wings may have served for species recognition, or for establishing dominance in the group, and (as is demonstrated in modern suids) helps protect the eyes and face when males battle with their sharp tusks.