Vertebrate dinoturbation from the Caturrita Formation (Late Triassic, Paraná Basin), Rio Grande do Sul State, Brazil

The Caturrita Formation is a lithostratigraphic unit that comprises the Ladinian–Eonorian sequence of the Paraná Basin. It has been interpreted as deposits of alluvial plains and meandering rivers. Purported fossil tracks found in this formation at Faxinal do Soturno County, Rio Grande do Sul State, Brazil, are concave circular-shaped structures, with a laminar deformation. Some show digitiform projections, and at least three are aligned. They are interpreted as a disruption of the substrate homogeneity caused by bioturbation of tetrapods. In some of these there is a distinct color pattern — more reddish than the surrounding substrate. This is interpreted as a result of differential diagenesis. The features remain enigmatic tracks but were probably made by prosauropod dinosaurs, the dominant terrestrial herbivore group from the end of the Triassic in Gondwana strata.