A new cynodont concentration from the Brazilian Triassic: Insights into the genesis and paleobiological significance of a highly productive fossil site

Bonebeds, concentrations of fossilized vertebrates, provide valuable insights into paleoecological, biostratigraphic, and macroevolutionary contexts, though they are often influenced by taphonomic processes. Brazilian Triassic rocks are notable for such fossil assemblages. Among these, the Várzea do Agudo site is remarkable for its abundance of fossils of the traversodontidae cynodont Exaeretodon riograndensis. Initial studies suggested that biogenic factors, especially scavenging and predation, were key to the formation of these bonebeds. This study aims to describe a new fossiliferous concentration from this site, analyzing the taphonomic and biostratinomic processes involved in its genesis. Our findings indicate that multiple factors, including biogenic actions and environmental conditions such as floodplain dynamics, contributed to the accumulation and preservation of the abundant bonebeds. This integrative approach enhances our understanding of the paleoecology of Exaeretodon riograndensis, which was probably a gregarious animal, and the environmental context of Hyperodapedon Assemblage Zone.