MAMMALS FROM THE SALICAS FORMATION (LATE MIOCENE), LA RIOJA PROVINCE, NORTHWESTERN ARGENTINA: PALEOBIOGEOGRAPHY, AGE, AND PALEOENVIRONMENT

DIEGO BRANDONI; GABRIELA SCHMIDT; ADRIANA CANDELA; JORGE NORIEGA; ERNESTO BRUNETTO; LUCAS FIORELLI

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2012 p. 375 - 387

0002-7014

This study analyzes a collection of fossil mammals from the Salicas Formation in the El Degolladito area, La Rioja Province, Argentina. The materials reported herein were recovered from two sites (site 1 and site 2) and are: Macrochorobates Scillato-Yané, Chasicotatus Scillato-Yané, and Hoplophorini indet. (Xenarthra, Cingulata); Paedotherium minor Cabrera, cf Pseudotypotherium Ameghino (Notoungulata, Typotheria); Neobrachytherium Soria (Litopterna, Lopholipterna); Orthomyctera Ameghino, cf. Cardiomys Ameghino, Lagostomus (Lagostomopsis) Kraglievich, and Octodontidae indet. (Rodentia, Caviomorpha). This new mammalian assemblage, together with one previously recorded, has several taxa in common with mammalian associations from Central Argentina (i.e., La Pampa Province). Among those coming from Northwestern Argentina, the major affinity is with the El Jarillal Member (Chiquimil Formation) and then the Andalhuala Formation (both in Catamarca Province). The Salicas Formation fauna is considered as latest Miocene in age until new fossil discoveries and radioisotopic dates allow a better calibration. The fossil biota and geological data suggests that the Salicas Formation was deposited in flatlands, under warm and dry conditions. This environment was dominated by open grasslands, with forested areas near rivers and lagoons. Key words. Mammals. Paleobiogeography. Paleoenvironment. Salicas Formation. Neogene. Northwestern Argentina.