Procyonidae (Mammalia, Carnivora) and the Great American Biotic Interchange

Laburpena

Members of the family Procyonidae were the first placental carnivorans to migrate from North America to South America, during the first part of the Great American Biotic Interchange (ProtoGABI). The Cyonasua group is an endemic South American radiation of procyonids, known from the Late Miocene to Middle Pleistocene. It includes Cyonasua argentina, perhaps four species of Amphinasua, one of Brachynasua, and two species of the remarkable, bear-like Chapalmalania. Some of the characters used to distinguish these taxa are likely caused by individual variation and sexual dimorphism. Early records of the Cyonasua group include fossils collected in 1926-27 by an expedition from the Field Museum of Natural History to Catamarca Province, Argentina. We illustrate and discuss the most important of these specimens. The Cyonasua group is the sister taxon of the North American Middle and Late Miocene Arctonasua. The extant genera Nasua and Procyon have a Pliocene record in North America and first occur in South America in the Early-Middle Pleistocene. The fossil record indicates that, for the most part, the genera of procyonidsevolved in North America before migrating to South America. Divergence dates determined from the fossil record are younger than those of the molecular clock.