CINGULATES (MAMMALIA, XENARTHRA) OF THE SANTA CRUZ FORMATION (EARLY-MIDDLE MIOCENE) FROM THE RÍO SANTA CRUZ, ARGENTINE PATAGONIA

Abstract

In 1887 Carlos Ameghino carried out the earliest extensive exploration of the fossiliferous localities along the Río Santa Cruz (Patagonia). His brother Florentino erected more than 100 vertebrate species based on the remains that Carlos recovered. The faunal assemblage eventually came to be recognized as the Santacrucian South American Land Mammal Age (Early–Middle Miocene). Over the past several years, an interdisciplinary group from the Museo de La Plata, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (Argentina), and Duke University (USA) revisited the Río Santa Cruz localities, including Barrancas Blancas, Segundas Barrancas Blancas, and Yaten Huageno. This contribution presents a taxonomic list of cingulates based on the abundant material recovered during these expeditions. In Barrancas Blancas, we recorded the armadillos Peltephilus pumilus Ameghino, Stenotatus patagonicus Ameghino, Proeutatus oenophorus Ameghino, Prozaedyus proximus Ameghino, and Stegotherium tessellatum Ameghino, and the glyptodonts Cochlops muricatus Ameghino and Eucinepeltus sp. Ameghino. We did not record St. tessellatum in Segundas Barrancas Blancas and St. tessellatum, P. pumilus and Eucinepeltus sp. in Yaten Huageno. The comparative analysis between the faunal composition of the Santa Cruz Formation in the Río Santa Cruz and other areas to the west and the east reveals minor differences that, preliminarily, suggest environmental differences between the analyzed regions.