THE OLDEST RECORD OF BONE DISEASES IN XENARTHRA (MAMMALIA)*

LUNA, CARLOS A.; BARBOSA FERNANDO H.S; QUIÑONES SOFIA I.; MIÑO-BOILINI ANGEL R.; ZURITA ALFREDO E.; CUARANTA PEDRO

Cordoba

Jornada; 33 JORNADAS ARGENTINAS DE PALEONTOLOGÍA DE VERTEBRADOS; 2019

Paleopathological studies are a useful tool for paleobiological and paleoecologicalinterpretations in different extinct vertebrate clades. The Xenarthra are one of thegroups of fossil mammals that has received the most attention regarding these type ofanalyzes in the last years. However, all pathological records are restricted to theQuaternary sloths and glyptodonts of South America. In this contribution we presentdifferent articular and vertebral lesions in three specimens of Simomylodon Saint-André et al., 2010 (Mylodontidae) from the Late Miocene-Pliocene of Jujuy Province(Northwestern Argentina). Although each individual show lesions in different degree,they present the same types of bones changes. The non-marginal syndesmophyte on theaxis/third cervical vertebrae (JUY-P-084) and on sacral vertebrae (JUY-P-185),marginal bone overgrowth and peripheral joint erosion on the lateral and medial condylein the femur (JUY-P-185) and articulate surface for tibia of the astragalus (JUY-P-089)are diagnostic of spondyloarthropathy (SpA).The presence of calcified plate-like on thejoint surfaces of the vertebrae of all individuals indicates the secondary development ofCalcium Pyrophosphate Deposition Disease (CPPD), a type of inflammatory,mechanical and crystalline arthritis, probably as a complication of SpA. On the otherhand, osteophytes on the edges of vertebral endplates are indicative of spondylosisdeformans, an aging condition. These lesions correspond to the oldest record ofpathologies in sloths, and in xenarthrans in general. Finally, it is noteworthy that allspecimens are adults having different body sizes, indicating that the development ofthese diseases seems to be unrelated to the weight of these mammals.