THE EVOLUTION OF NORTH AMERICAN PECCARIES

The family Tayassuidae (peccaries or javelinas) is a group of New World suiform artiodactyls with an ecology much like that of the family Suidae, the true pigs of the Old World. Their last common ancestor with the family Suidae was over 37 million years ago, and since then tayassuids have evolved and diversified in isolation in North America (and eventually South America) independent of the suids. Even though there are only three living genera in the Americas today, peccaries were once much more diverse. Previous studies recognized only 7-12 genera of peccaries in North America, but very little research has been published on them in decades, and most of that research became obsolete with the large collections of good specimens newly available. I recognize 26 genera and 35 valid species in North America (all but one of them extinct). The earliest tayassuids included the genera Perchoerus and Thinohyus from the late Eocene to late Oligocene, followed by a late Oligocene-early Miocene radiation of the hesperhyine peccaries (8 genera and 8 species). Meanwhile, in the early and middle Miocene, the main lineages of Tayassuinae diversified, culminating with 10 genera (3 of them new) in the middle-late Miocene. Many of these late Miocene peccaries had a variety of bizarre ridges and crests flaring out from their cheekbones. The paraphyletic wastebasket taxon Prosthennops had long obscured this diversity of late Miocene peccaries, but that genus is now restricted to only its type species. By the latest Miocene, peccary diversity reduced to just a few genera, culminating with the two common Pliocene-Pleistocene genera, the flat-headed peccary Platygonus, and the long-nosed peccary Mylohyus. A new phylogeny of the family is proposed, based on a large suite of characters from not only the teeth and skulls, but also in the maxillo-palatine and choanal region unknown to most previous workers. Much of what is written online and in the paleobiological databases about peccaries is now obsolete. As a result, diversity curves based on the outdated information on the PBDB are completely the opposite of the actual pattern. Fossils of the group are so rare and unpredictable in their occurrence that peccaries cannot be used for robust biogeographic analyses.