Una nueva especie de Holmesina Simpson (Xenarthra, Cingulata, Pampatheriidae) del Pleistoceno de Rondônia, Sudoeste de la Amazonia, Brasil

GÓIS, F.; SCILLATO-YANÉ, G.J.; CARLINI, A.A; UBILLA, M.

REVISTA BRASILEIRA DE PALEONTOLOGIA

SOC BRASILEIRA PALEONTOLOGIA

Lugar: Porto Alegre; Año: 2012 vol. 15 p. 211 - 227

1519-7530

The Xenarthra Cingulata are one of the most characteristic groups in the Neotropical Region; these American endemic mammals comprise several families. Among them, the Pampatheriidae (middle Miocene early Holocene) are characterized by sharing traits with both the Dasypodidae and the Glyptodontidae. The genera Pampatherium Gervais and Ameghino, 1880, and Holmesina Simpson, 1930, occur in both North and South America. In North America, the species H. floridanus, H. septentrionalis and P. mexicanum are recorded from the late Pliocene to the Pleistocene, whereas H. occidentalis, H. paulacoutoi, H. majus, P. humboldtii and P. typum are recorded in the Pleistocene of South America. Holmesina rondoniensis differs from the other Holmesina and Pampatherium species by a series of distinctive morphological and allometric features: markedly slender skull, narrow straight nasals, slightly convex frontals, long parietals, and little developed sagittal crest. Zygomatic arch long and slender, without a large lateral area at orbital level as in the other species; infraorbital process absent. Temporal fossa wide and excavated/deep; supraoccipital very high, deep, with external occipital crest prominent and lambdoid crest expanded posteriorly. Palate narrow, with imbrication molariforms between MF2, MF3 and MF4. H. rondoniensis is based on a skull without mandible found at the locality Araras/Periquitos, right margin of Madeira river, Municipality of Vila Nova Mamoré, state of Rondônia, from the Rio Madeira Formation (late Pleistocene to early Holocene).