New vertebrate assemblage from the Brochero Formation (Late Pliocene), Córdoba Privince, Argentina)

CRUZ, L.E.; FERNICOLA, J. C.; CARIGNANO, C. A.; BARGO, M. S.; BOND, M.; BRIZUELA, S.; CANDELA, A. M.; DESCHAMPS, C. M.; KALUZA, J.; ORTIZ, P.; PARDIÑAS, U. F. J.; PÉREZ BEN, C.; TETA, P.; VECETICH, M. G.

Mendoza

Congreso; 4th International Palaeontological Congress; 2014

Asociación Paleontológica Argentina

The Brochero Formation ("Horizonte Brocherense" of Castellanos) was created on the basis of amammal assemblage from its type locality Valle de Traslasierra (San Alberto Department), and fromValle de Los Reartes (Calamuchita Department), both in Córdoba Province, Central Argentina. Thelist of taxa included: Nonotherium and Paedotherium (Notungulata); Plaina, Propanochthus, Nopachthus and Plohophorus (Xenarthra, Cingulata); Orthomyctera, Ctenomys and Paleocavia (Rodentia); and Felidae indet. (Carnivora). In 1944, this mammal association was assigned by Castellanos to his "Uquian Stage" (early Pliocene for Castellanos). Later, diffrent authors considered this association either Montehermosan Stage/Age (early Pliocene) or Huayquerian Stage/Age (late Miocene). Here we present new vertebrates from the Brochero Formation, recovered in recent fild trips to the type locality, and discuss the age of the fauna and its bearing sediments. This stratigraphic unit crops out along the Valle de Traslasierra and is composed by two red beds facies normally graded, with discontinuous laminate and nodular calcretes. The basal facies is a very fie matrix-supported conglomerate; the grain size is sabulitic and the matrix is sandy silt. The upper facies is a fine sandy to clayed silt with paleosoils. The vertebrates recovered include the following taxa: the anurans Rhinella cf. R. arenarum and R. cf. R. spinulosa (Bufonidae); squamate reptiles represented by snakes ("Colubridae" indet.) and diffrent lizards: Teius sp. (Teiidae), Iguanidae indet. and Tropidurinae indet. Within mammals, Rodentia are represented by "Akodon (Abrothrix)" magnus and a new, still unnamed, genus (Cricetidae), Phugatherium cf. P. novum  (Hydrochoeridae), and an Echimyidae indet; xenarthrans include the cingulates Doellotatus cf. D. chapadmalensis (Dasypodidae) and Panochthidae indet. Snakes, lizards, Rhinella cf. R. spinulosa, the rodents, and the dasypodid are fist records for the Brochero Formation. Phugatherium novum is recorded in the Chapadmalalan (late Zanclian-early Piacenzian), whereas "Akodon (Abrothrix)" magnus is recorded in the Vorohuean (Piacenzian) in the Atlantic coast of Buenos Aires Province. These new records suggest that the Brochero Formation would have been deposited in the late Zanclean-Piacenzian interval. However, in order to refie its age further analyses and fild works are needed.