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In Brazil, the Quaternary caves of the Brazilian Intertropical Region (BIR) host important fossiliferous deposits of terrestrial vertebrates, whose fossil content is taxonomically well known. Here, we conducted a taphonomic analysis based on macroscopic and microscopic features of 543 specimens collected in the F3 cave, a fossiliferous deposit located in the municipality of Baraúna, northeast of Brazil. This deposit encompasses 17 taxa, but it is dominated by fossils of Eremotherium laurillardi. Most bones were buried in less than a year, but the taphonomic history of this deposit was governed by alternation of dry and wet cycles. This led us to recognize four taphonomic modes, that differ according to the climatic conditions in which the bones were preserved as well as the time interval between the accumulation and the final burial of the remains.

Arthritic lesions have been frequently diagnosed in the fossil record, with spondyloarthropathy (a type of erosive and pan-mammalian arthritis) being one of the most common types described to date for mammals, though not restricted to this group. Here, we identify spondyloarthropathy in fossil bones from the late Pleistocene in Brazil assignable to a large glyptodont individual. Bone erosions in the peripheral joints (viz., the ulna, radius, left femur and tibiae-fibulae) associated with osteosclerosis allow the diagnosis of spondyloarthropathy. The presence of osteophytes in seven bones of the forelimbs (viz., the ulna and radius) and hind limbs (viz., the tibiae-fibulae, left femur and patellae) and a subchondral cyst in one element (viz., the left femur) indicate secondary osteoarthritis. A calcified deposition on the articular surface of the left patella indicates the presence of calcium pyrophosphate deposition disease, which, like the observed osteoarthritic alterations, likely represents a complication of spondyloarthropathy. This is the first report of spondyloarthropathy for xenarthrans.