Overview on the tetrapods from Faixa Nova-Cerrito I site (<i>Hyperodapedon</i> Assemblage Zone), Upper Triassic of southernmost Brazil

The Faixa Nova-Cerrito I site, in the municipality of Santa Maria, Rio Grande do Sul, Brazil, displays rock layers from the <i>Hyperodapedon</i> Assemblage Zone (AZ), Carnian age of 233.23 ± 0.73 Ma (based on data collected in the nearby and correlated ‘Alemoa’ area), Santa Maria Supersequence, Upper Triassic, Paraná Basin. The new postcranial remains studied are referred to as Dinosauriformes indet., Silesauridae indet., <i>Gnathovorax cabreirai</i> (Herrerasauridae), and a Chiniquodontidae cynodont, all collected between 1996 and 2002, during the Pro-Guaíba project. The identification of specific groups like silesaurids, herrerasaurids and chiniquodontids for the first time in this outcrop adds valuable nuances to the biostratigraphical framework of the Brazilian Upper Triassic record. These findings straighten the correlation of the basal layers of Faixa Nova-Cerrito I Site with other <i>Hyperodapedon</i> Acme Subzone outcrops and provide some insights on the diversity of the upper <i>Teyumbaita</i>-layers. Our result in part corroborates the current hypothesis for the subdivision of the <i>Hyperodapedon</i> AZ, but the probable silesaur occurrence within the <i>Teyumbaita-</i>layers does not yet indicate that those levels are equivalent to those from the <i>Exaeretodon</i> Subzone. Our results highlight the importance of even fragmentary specimens in biostratigraphy and diversity estimations.