Megafauna from the Late Pleistocene-Holocene deposits of the Upper Ribeira karst area, southeast Brazil

摘要

The carbonate caves of the Upper Ribeira Valley, southeastern Sao Paulo State, Brazil, preserve an abundant fossil record of Pleistocene-Holocene South American megafauna. Nevertheless, in comparison with other localities of the country, its paleontological knowledge still can be considered sparse and in need of further research. This work presents an update taxonomic survey of the megafauna material collected since the beginning of the explorations in the area. Based on this, it discusses paleobiogeo-graphic and paleoecological questions. The fossil megafauna of the Upper Ribeira karst region include: Eremotherium laurillardi, Nothrotherium maquinense, Lestodon armatus, Catonyx cuvieri, 'Ocnopus gracilis', Ahytherium aff. aureum, Glyptodon clavipes, G. reticulatus, Hoplophorus cf., Toxodon spp., Stegomastodon waringi, Equidae (Hippidion cf.), Tapirvs terrestris, Panthera onca and Smilodon populator. Only P. onca and T. terrestris still remain in the region. Despite the occurrence of some typical taxa of the pampean paleobiogeographical province, the fossil assemblage recorded shows greater affinity to the mega-mammal community of the intertropical region. The ecology of species found suggests the previous occurrence of fairly different environmental settings than the existing one in the area. There were more temperate climates - both dry and wet - until the current mesophytic forest was finally established. The studied material does not show any kind of chrono-correlation, given the type of genesis of the cave accumulations. These fossils depict different faunistic moments related to climate changes during the Quaternary. To better understand the information provided by these deposits, efforts on dating and detailed taphonomic investigations should be conducted. The studies of the Quaternary fauna in the state of Sao Paulo fill an important gap in the intricate biogeographical history of the South American megafauna.