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

ABSTRACT

The Faixa Nova-Cerrito I site, in the municipality of Santa Maria, Rio Grande do Sul, Brazil, displays rock layers from the Hyperodapedon 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., Gnathovorax cabreirai (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 Hyperodapedon Acme Subzone outcrops and provide some insights on the diversity of the upper Teyumbaita-layers. Our result in part corroborates the current hypothesis for the subdivision of the Hyperodapedon AZ, but the probable silesaur occurrence within the Teyumbaita-layers does not yet indicate that those levels are equivalent to those from the Exaeretodon Subzone. Our results highlight the importance of even fragmentary specimens in biostratigraphy and diversity estimations.

KEYWORDS:

• Dinosauriformes
• Herrerasauridae
• Chiniquodontidae
• taxonomy
• Carnian

Acknowledgments

We thank Á.A.S. Da-Rosa (UFSM), Cesar L. Schultz (UFRGS) and Rodrigo T. Muller (UFSM-CAPPA) of the Universidade Federal de Santa Maria (UFSM) for helpful comments. We thank Lisie Damke (UFSM-CAPPA) and Mauricio Schmitt (FURB) for sharing some photographs used in Figure 8. We are also thankful to the Pro-Guaiba Project for the field grant and the Museu de Ciências Naturais da Secretaria Estadual do Meio Ambiente e Infraestrutura (MCN-SEMA), Porto Alegre, for the granted infrastructure. In addition, we would like to thank the reviewer Agustín Martinelli and the anonymous reviewer for their valuable comments and recommendations which contributed significantly to the improvement of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08912963.2024.2344791.

Additional information

Funding

M.C.L. and F.O.S are supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). A.M.R. is supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [CNPq PQ310023/2021-1].