LATE MIOCENE DASYPODIDAE (XENARTHRA, CINGULATA) FROM THE TORO NEGRO FORMATION (CENTRAL ANDES, ARGENTINA)

BRANDONI, DIEGO; BARASOAIN, DANIEL; GONZÁLEZ RUIZ, LAUREANO R.

Congreso; XII Congreso de la Asociación Paleontológica Argentina; 2021

The presence of several taxa of Cingulata (Mammalia, Xenarthra) were mentioned for the lower member of the Toro NegroFormation at La Rioja Province, i.e., the dasypodids Proeuphractus limpidus, Chorobates villosissimus, Paleuphractus sp., and Doellotatus inornatus; and the glyptodontids Lomaphorops corallinus, Neuryurus cf. giganteus, and cf. Urotherium. Most of thedescribed fossil vertebrates from the Toro Negro Formation (including the dasypodids) were collected at Quebrada de La Troya site, in the proximity of the road between the localities of Vinchina and Jagüel. In turn, the remains herein described and referred to different species of Dasypodidae (Mammalia, Xenarthra, Cingulata) come from the upper levels of the lowermember of the Toro Negro Formation at Quebrada de Las Torrecillas, where previous vertebrate records in the area just include those of Pyramiodontherium scillatoyanei (Mammalia, Xenarthra, Megatheriinae) and Opisthodactylus cf. kirchneri (Aves, Rheidae). The most accurate proposed age suggests a Messinian–zanclean age (late Miocene–Early Pliocene) for the lower member of the Toro Negro Formation. The described specimens are currently housed at the collection ofDepartamento de Geociencias, Centro Regional de Investigaciones Científicas y Transferencia Tecnológica, Anillaco, La Rioja, Argentina (CRILAR, Anillaco, La Rioja, Argentina). The records of Dasypodidae herein presented include: Vetelia ghandii, Chasicotatus peiranoi, Macrochorobates scalabrinii, Prozaedyus sp., and Paleuphractus argentinus. These records constitutethe first ones of these species for the Toro Negro Formation, increasing the mammal diversity for this unit. The association of dasypodids here described shows strong affinities with those described for late Miocene localities of Northwestern Argentina, such as Loma de Las Tapias Formation in San Juan Province, and Playa del zorro Alloformation, and Chiquimil,and Andalhuala formations in Catamarca Province. Both V. ghandii and Pal. argentinus, and possibly C. peiranoi, represent endemic species of northwestern Argentina with a very restricted biochron to the late Miocene (ca. 9–7.14 Ma). Regarding Prozaedyus, it was recorded for the late Miocene (ca. 9 Ma) of San Juan Province, Argentina. In turn, M. scalabrinii is the only among the recovered species which is recorded both for late Miocene and Early Pliocene deposits. Under these evidences, the Dasypodidae here reported for Quebrada de Las Torrecillas site show a characteristic association of taxa from the Subandean region of western Argentina, suggesting a Messinian age (late Miocene) for the bearing levels of the Toro Negro Formation. This way, these records support the most accurate proposed ages for the lower Member of the Toro NegroFormation (i.e., late Miocene–Early Pliocene).