New late miocene records of Dasypodidae (Xenarthra, Cingulata) from the Salicas Formation (La Rioja province, Argentina)

Abstract

The Neogene deposits of the Salicas Formation outcrop along the northern area of the Velasco Range. Their levels have provided several remains of mammals, including notoungulates, liptoterns, rodents, and xenarthrans. Focusing on Dasypodidae (Xenarthra, Cingulata), the record from La Rioja is fragmentary and has been less studied compared to other provinces with late Neogene localities in northwestern Argentina (i.e., Catamarca). Previous records from the formation include Chaetophractus sp., Proeuphractus limpidus, Proeuphractus sp., Macrochorobates scalabrinii, Macrochorobates sp. and Chasicotatus sp. In this contribution, we describe new specimens of Dasypodidae from the area of "El Degolladito" of the Salicas Formation, housed at the CRILAR collection (Anillaco, La Rioja, Argentina). The new described materials consist in several isolated osteoderms of the dorsal carapace of different taxa, including the Euphractinae Eutatini Chasicotatus peiranoi, the Euphractinae Euphractini Macrochorobates scalabrinii, Chorobates villossisimus, Paleuphractus argentinus and Prozaedyus sp., and the Tolypeutinae Priodontini Vetelia ghandii. These records substantially increase the Xenarthra diversity known for the Salicas Formation, while providing specific determinations of some previously mentioned genera. Though there are no radiometric dating for the Salicas Formation, the Dasypodidae association here recorded suggests a late Miocene age (Tortonian-Messinian) for the bearing levels of "El Degolladito", supporting the previously proposed ages. Additionally, C. peiranoi, P. argentinus and V. ghandii have been recorded over several late Miocene deposits in Northwestern Argentina, such as Loma de Las Tapias (San Juan), Chiquimil and Andalhuala (Catamarca), and Toro Negro (La Rioja) formations, suggesting an endemic Dasypodidae diversity in subandine areas during this lapse.