The skeleton of the manus of Scelidotherium (Xenarthra, Mylodontidae) specimens from the Pleistocene of the Province of Córdoba, Argentina, and its systematic implications

NIETO, G.; HARO, A.; MCDONALD, H.G.; MIÑO BOILINI, A. R.; TAUBER, A.; KRAPOVICKAS, J.; FABIANELLI, M; ROSAS, F

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Lugar: Berlin; Año: 2021 vol. 28 p. 221 - 243

1064-7554

Dental and craniomandibular data have been predominantly used to infer relationships among mylodontid ground sloths. Recentstudies indicate the osteology of the manus also provides useful data to test phylogenetic relationships in mylodontinemylodontids. Here we provide new comparative data from the study of the manus of a member of the Scelidotheriinae, Scelidotherium Owen, 1839, based on specimens from the Province of Córdoba that provide information on the variation andsystematic relationships of the genus. The Scelidotherium material from the Province of Córdoba in central Argentina presentsseveral morphological differences with material of the genus from northwestern Argentina. The manus of Scelidotherium sharesseveral traits with Catonyx Ameghino, 1891, but not with Valgipes Gervais, 1874. These include: trapezoid with a sharp ridge onthe articular surface for metacarpal II; magnum with at least half of articular surface for metacarpal II located on the dorsal half ofthe medial and distal aspects of the bone; metacarpal II with a notch on the axial border of its distal articular surface; and ungualprocess of the distal phalanx of the second digit markedly dorsopalmarly flattened. A phylogenetic analysis that includesosteological characters of the manus indicates that within the family Scelidotheriinae, Scelidotherium is more closely relatedto Catonyx than to Valgipes or Proscelidodon gracillimus Rovereto, 1914.