Bone diseases in a Pleistocene South American native ungulate species: the case of Toxodon platensis Owen, 1837 (Mammalia, Notoungulata, Toxodontidae)

LUNA, C.; BARBOSA,F; GONZALEZ, R.; MIÑO BOILINI, A. R.; REPETTO, C.; ZURITA, A.E.

JOURNAL OF QUATERNARY SCIENCE

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2024 p. 1 - 10

0267-8179

Knowledge of bone pathologies in South American native ungulates is very scarce, which contrastswith other groups of megamammals such as xenarthrans and proboscideans. In this paper, based on morphologicaland histological analysis, we describe different bone pathologies in two specimens of Toxodon platensis Owen(Notoungulata), one of the most common taxa in the Late Pleistocene faunistic associations of northeastern Argentina.Subchondral erosions on the metacarpus and magnum, non‐marginal syndesmophytes and enthesitis on the vertebralbody, the neural column and the zygapophyseal joint of the lumbar vertebrae, as well as a particular periostealreaction on the ribs, have been interpreted as manifestations of spondyloarthropathies in one of the analyzedindividuals. In the same individual, a process of fusion and bone neoformation is observed in the caudal vertebrae,which seems to correspond both to the aforementioned spondyloarthropathy and to an infectious process. A lesionon the fourth metatarsus of a second individual with an evident cloaca is suggestive of osteomyelitis; this is the firstreport of this pathology in notoungulates. It seems possible that some of these pathologies may have been facilitatedby factors such as body mass, mode of locomotion or environment. These findings provide insight into some aspectsof the ecology of this particular group of extinct South American megamammals.