A new geographical record of Abelisauridae (Theropoda, Dinosauria) for the Bauru Group (Upper Cretaceous)

Abstract

Theropod teeth allow high-rank group assignments based on both phylogenetic positioning and morphometry. To the Bauru Group, abelisaurid distribution is known mostly from isolated teeth from relatively few localities. Based on teeth we extend their distribution to Ituiutaba, NNE of the basin. Teeth specimens from the neighboring Prata county, historically attributed to Carcharodontosauridae and Abelisauridae were also analyzed. For taxon assignment, we used methods such as phylogenetic, discriminant analysis, and direct comparisons. In our phylogenetic analysis, all teeth were recovered within abelisaurids whereas in the discriminant analyses, they nested close or within abelisaurids, neovenatorids, and dromaeosaurids. Therefore, our analyses support that teeth from Ituiutaba/Prata can be assigned to Abelisauridae, evidencing a continuous spatial distribution along the Bauru Group and those sites overlaying the Serra Geral formation in the southeastern state of Mato Grosso. Further studies at Ituiutaba, including information on the associated fauna, may subsidize the understanding of abelisaurid ecological requirements and the paleoenvironment of the Adamantina Formation.