A NEW LATE TRIASSIC 1 VERTEBRATE ASSEMBLAGE FROM 2 NORTHWESTERN ARGENTINA

MARTÍNEZ, RICARDO NESTOR; APALDETTI, CECILIA; CORREA, GUSTAVO; CARINA COLOMBI; FERNÁNDEZ, ELIANA; SANTI MALNIS, PAULA; PRADERIO, ANGEL; ABELIN, DIEGO; LAURA BENEGAS; ANDREA CAMEO; ALCOBER, OSCAR

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2015 vol. 52 p. 379 - 390

0002-7014

The Quebrada del Barro Formation (QBF) is part of 24 the continental Marayes-El Carrizal Basin, at NW Argentina. In 2013 we briefly reported the discovery of the first vertebrate association on QBF?from the ?Bone-bed? locality?composed mainly by opisthodontian sphenodonts, basal sauropodomorph dinosaurs, tritheledontid cynodonts, and pseudosuchians. In 2014 we discovered a new fossiliferous locality sited at the upper leyers of the QBF?informally called ?Quebrada del puma??characterized by the abundance and diversity of fossil vertebrates. Here, we report the preliminary list of the findings in both aforementioned fossil localities of the QBF. The new discoveries evidence a vertebrate association that includes remains of at least 12 different new species related to six main vertebrate groups: Cynodontia, Testudinata, Sphenodontia, Pseudosuchia, Pterosauria, and Dinosauromorpha. Several of the new findings are equivalent with those of the Los Colorados Formation (LCF), although preliminary study suggests that those are not the same specific taxa and the relative abundance of different taxonomic groups are also different. Therefore, the new faunal assemblage seems to be not exactly contemporary to that from LCF, and consequently we suggest the late Norian?Rhaetian age for the QBF. The specimens listed here represent new cynodont, archosaur, and lepidosauromorph taxa that will provide additional information on the diversity of these three major groups of vertebrates during the Late Triassic in South America. This underscores the importance of the QBF fauna for achieving an understanding of the evolution of the major vertebrates groups that dominated the terrestrial ecosystems during the early Mesozoic across Pangea.