Glyptodontidae (Xenarthra, Cingulata) Of the Tarija Valley (Bolivia): Systematic, Diversity, Biostratigraphic and Paleobiogeographic Aspects of a particular assemblage

ZURITA, A. E.; MIÑO BOILINI, A. R.; SOIBELZON, E.; CARLINI, A. A.; PAREDES RÍOS, F.

Neuquén

Congreso; III Congreso Argentino de Cuaternario y Geomorfología; 2008

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The Tarija Valley (21º 31' S and 64º 43' W) is located approximately 1000 km south from La Paz (Bolivia) and it extends for approx. 4500 km2, at nearly 2000 m above sea level (MacFadden and Shockey, 1997). From a historical perspective, the sedimentary sequences that crop out in Tarija Valley have been successively assigned to different ages and stages ranging from the Lower to the Upper Pleistocene (see, among others, Ameghino, 1902; MacFadden, 2000; Coltorti et al., 2007). In this context, the faunal assemblage of Cingulata Glyptodontidae is among the most frequent elements of the megafauna known for this place (Hoffstetter, 1963; Werdelin, 1991; Coltorti et al., 2007). Here, a revaluation on the main systematic, biostratigraphic and paleobiogeographic aspects of the Glyptodontidae fauna from the Pleistocene of Tarija Valley, are presented. The Glyptodontidae assemblage of this area is unique with respect to faunas known for other areas of South America. Some noteworthy features are the abundance of remains assignable to genus Glyptodon Owen, and the scarcity or absence of others (Panochthus Burmeister and Neosclerocalyptus Paula-Couto) that are very frequent in the fossil record of the Pampean and north-central regions of Argentina. The validity of Hoplophorus echazui Hoffstetter, as well as the presence of H. euphractusLund and P. tuberculatus (Owen) are questioned pending the finding of more complete materials, and all the records assigned to Neothoracophorus Ameghino may very probably correspond to subadult Glyptodon specimens. Biostratigraphically, all but one of the Glyptodon specimens are highly morphologically similar to those from the middle Pleistocene- early Holocene (Bonaerian-Lujanian) of the Pampean region in Argentina. However, one of the specimens studied (MNPA-v 006118) from the locality Armados, corresponds to the species G. munizi Ameghino, restricted to the Ensenadan (late Pliocene- early middle Pleistocene) in the Pampean region (Soibelzon et al., 2006).