First record and description of an exceptional unborn specimen of Cingulata Glyptodontidae: Glyptodon Owen (Xenarthra)

ZURITA, A. E; MIÑO-BOILINI, A.R.; SOIBELZON, E.; SCILLATO-YANÉ, G. J.; GASPARINI, G. M.; PAREDES-RIOS, F.

San Rafael, Mendoza

Jornada; XXI Jornadas Argentinas de Paleontología de Vertebrados; 2009

Asociación Paleontológica Argentina

In this paper, we report the first discovery and description of an unborn specimen of Cingulata Glyptodontidae. The specimen was found inside a well-preserved dorsal carapace assignable to Glyptodon cf. G. elongatus Burmeister (MNAP-v 6146), partially articulated and located in the pelvic portion. It was excavated from Pleistocene sediments of Monte Cercado, Tarija Valley (Bolivia), and it consists of a partial skull, a mandible with molariforms (m4-m8), the distal half of both scapulae, the diaphysis of both femora, and other unidentified remains. From an anatomical perspective, certain characteristics of the skull of this specimen are remarkable similar to those present in fully developed individuals (i.e. subtriangular outline of the narial aperture); however, the ascending ramus of the mandible describes an angle close to 90° relative to the horizontal ramus. The only previous mention of an unborn Glyptodontidae comes also from Tarija Valley, but that material is lost. Finally, it is interesting to note that, from a biogeographic and paleofaunistic point of view, and in contrast to what it can be observed in other areas of South America (e.g., Chaco-Pampean region of Argentina, Mesopotamian region, southern Brazil and western Uruguay), the Glyptodontidae record of Tarija Valley show certain peculiarities, such as the high frequency of Glyptodon Owen, and the absence (e.g., Neosclerocalyptus Paula Couto) or scarcity of others (e.g., Panochthus Burmeister).