New paleopathological findings from the Quaternary of the Brazilian Intertropical Region expand the distribution of joint diseases for the South American megafauna

Abstract

ObjectiveTo evaluate pathological changes in fossils from the Brazilian Intertropical Region (BIR), expanding the records of previously reported diseases for representatives of the Quaternary South American megafauna, including taxa not studied in previous works. Materials and methodsWe carried out a thorough macroscopic analysis of fifteen unpublished specimens belonging to representatives of the Quaternary megafauna of BIR to identify evidence of pathological alterations. ResultsAlterations included: osteophytes in Toxodontidae, Megatheridae and E. laurillardi; rough subchondral bone, bone overgrowth and bone erosion in E. laurillardi; slit-shaped subchondral depressions in Equidae and E. laurillardi; and a triangular-shaped porous lesion in Mylodontidae. ConclusionsThe alterations found allowed the recognition of the first cases of osteoarthritis for Toxodontidae and articular depressions for Equidae, and new cases of both diseases in Eremotherium laurillardi; a new case of osteochondritis dissecans for Mylodontidae; potential new cases of calcium pyrophosphate deposition and spondyloarthropathy for E. laurillardi SignificanceOur results provide additional evidence that calcium pyrophosphate deposition disease was widely spread among species of the South American megafauna and suggest that osteochondritis dissecans may have been relatively common among ground sloths. LimitationsThe identification of calcium pyrophosphate deposition and spondyloarthropathy in E. laurillardi are quite tentative because the evidence found is ambiguous and the number of examined specimens is limited.