New Pleistocene remains of megalonychid ground sloths (Xenarthra: Pilosa) from the intertropical Brazilian region

摘要: The Pleistocene fossil sloth Australonyx aquae De Iuliis, Cartelle, and Pujos, 2009 (Mammalia, Xenarthra, Megalonychidae) was described from the intertropical region of Brazil. However, its mandible not known only cursory descriptions ear ossicles were included. subsequently recognized among remains originally collected type locality, belongs to holotype individual. As a particularly important skeletal element for specific recognition, it requires description complement our understanding this species. ossicles, usually poorly represented in record, require further allow differentiation those other sloths. Comparisons are conducted with homologous elements contemporaneous sympatric Ahytherium aureum 2008, megalonychid Brazil, reinforce distinction between these two species detailed their initial descriptions. sloths (e.g., Acratocnus, Megalonyx, Neocnus) also reveal differences Au. such features as form size caniniform tooth, angular process, mandibular condyle. Differences malleus incus several clades clade level distinctions Megatheriidae, Nothrotheriidae, Megalonychidae. A well-preserved skull Brazilian state Rondonia is noted probably belonging aquae. This cannot be assigned formally because deposited institution, but does extend considerably range