caa a22 4500 445326239 CHVBK 20180317142721.0 cr unu---uuuuu 170323e20110601xx s 000 0 eng 10.1007/s10914-010-9147-5 doi (NATIONALLICENCE)springer-10.1007/s10914-010-9147-5 Grazing in a New Late Oligocene Mylodontid Sloth and a Mylodontid Radiation as a Component of the Eocene-Oligocene Faunal Turnover and the Early Spread of Grasslands/Savannas in South America [Elektronische Daten] [Bruce Shockey, Federico Anaya] We describe a new taxon of mylodontid sloth from the late Oligocene (Deseadan South American Land Mammal "age”), Salla Beds of Bolivia. This taxon, Paroctodontotherium calleorum, new genus and species, is one of the oldest known sloths, but it is surprisingly derived. It is referable to the Mylodontidae and, with just a little doubt, to the Mylodontinae. It shares a number of derived characteristics with other mylodontids and even mylodontines. These include: a relatively low temporomandibular joint; a relatively short zygomatic process of the squamosal; an elongated, narrow braincase; anteriorly diverging toothrows; broad muzzle; and greatly enlarged external nares. The relative width of the muzzle of Paroctodontotherium is as great as any Pleistocene mylodontid except the giant grazer, Lestodon. We review and critique methods of estimating diets of extinct sloths and propose a hypothesis in regard to the feeding ecology of Paroctodontotherium. Based upon its broad muzzle, the degree of tooth wear, and its presence in a habitat dominated by hypsodont herbivores, we propose that Paroctodontotherium was a bulk feeder that foraged near ground level. Grasses were likely a major component of its diet. The addition of this new taxon, along with other recently discovered taxa, illustrates that late Oligocene sloths had much greater diversity than recognized just a decade ago. This diversity is evident in species richness, variations in body sizes, dental morphologies, and means of locomotion. We regard this relatively sudden sloth radiation as a significant component of the Eocene-Oligocene faunal turnover and was related to the development of more open habitats of post-Eocene South America. Springer Science+Business Media, LLC, 2010 Folivora nationallicence Sloth nationallicence Deseadan nationallicence Eocene-Oligocene turnover nationallicence Grazing nationallicence South America nationallicence Shockey Bruce Biology Department, Manhattan College and the Department of Vertebrate Paleontology, American Museum of Natural History, New York, NY, USA aut Anaya Federico Facultad de Ingeniería Geológica, Universidad Autónoma Tomás Frías, Potosí, Bolivia aut Journal of Mammalian Evolution Springer US; http://www.springer-ny.com 18/2(2011-06-01), 101-115 1064-7554 18:2<101 2011 18 10914 https://doi.org/10.1007/s10914-010-9147-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10914-010-9147-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shockey Bruce Biology Department, Manhattan College and the Department of Vertebrate Paleontology, American Museum of Natural History, New York, NY, USA aut NATIONALLICENCE 700 1- Anaya Federico Facultad de Ingeniería Geológica, Universidad Autónoma Tomás Frías, Potosí, Bolivia aut NATIONALLICENCE 773 0- Journal of Mammalian Evolution Springer US; http://www.springer-ny.com 18/2(2011-06-01), 101-115 1064-7554 18:2<101 2011 18 10914 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer