Chapalmalania
Chapalmalania is an extinct genus of procyonid from the Late Miocene or Early Pliocene to Early Pleistocene of Argentina, Venezuela, and Colombia.
Description
Originally misidentified as a kind of bear, Chapalmalania is in fact a giant relative of raccoons and coatis, estimated to have weighed between to, comparable in mass to small/medium sized ursids such as the American [black bear] and spectacled bear.Evolution
Such a drastic size increase compared to its North America cousins likely stems from a rapid evolutionary response upon arriving in South America, with Chapalmalania evolving from the "dog-coati" Cyonasua, which probably island-hopped from Central America during the late Miocene, making them perhaps the earliest southward mammalian migrants of the Great [American Interchange], and one of the few documented cases of trans-oceanic dispersals of carnivorous mammals. It is thought the reason for this comes down to various aspects of procyonid biology that grant higher success at dispersing across ocean barriers than other carnivores. First, procyonids are excellent climbers, and can cling onto floating rafts of vegetation more effectively than more terrestrial carnivores. Secondly, their omnivorous diet allows them to take advantage of more food options when stranded out to sea, extending their survival and thus increasing their chances of making it to land. Finally, hypo carnivores like procyonids live at higher densities than mesocarnivores or hyper carnivores like mustelids, felids, and canids, thereby naturally increasing their chances at being swept out to sea in the first place due to greater abundance. Three other instances of trans-oceanic dispersal are documented among procyonids that further support these claims in practice, being the Cozumel Island Raccoon, Tres Marias Raccoon, and the Cozumel coati.It is thought that as the Isthmus of Panama rose from the sea to allow further invasions by other North American species, Chapalmalania was unable to compete and its lineage became extinct, especially with the arrival of Tremarctinae bears which appear to share similar dental morphologies with the large procyonid. However, it is also possible the extinction of Chapalmalania was due to climatic changes that occurred during the Pleistocene that wiped out a number of the continent's native fauna, with bears filling in the empty niches upon their arrival to the continent during the Late Uquian.