A SMALL TOOTH REVEALS THE FIRST RECORD OF AN ABELISAURID THEROPOD FROM THE LOWER CRETACEOUS FELIZ DESERTO FORMATION (NE, BRAZIL)

Abstract

We report here the first record of Abelisauridae in Sergipe, Brazil, through the taxonomic identification of an isolated tooth (LPUFS 5969) recovered from the Canafístula 01 outcrop. This fossiliferous locality includes part of the Berriasian–Valanginian time interval (Lower Cretaceous) being geologically composed of sandstones and siltstones deposited in a lacustrine-deltaic paleoenvironment. To test the phylogenetic position of LPUFS 5969, cladistic analyzes were carried out including the specimen in a taxon-character matrix focused on theropod dinosaur dentition. LPUFS 5969 consists of a nearly complete dental crown with the following features: mesiodistal main plane of curvature; ziphodont dentition with true denticles; lanceolate outline of the base in trans-versal section; lacking transverse undulations or longitudinal flutes; sub-rectangular denticles arranged parallel to the mesial carina and apically recurved in the distal carina. Our cladistic analysis recovered three MPTs grouping LPUFS 5969 in the Abelisauridae clade, sharing the following synapomorphies: weak crown elongation; rectilinear and centrally positioned mesial carina; and denticles of the distal carina uncinate apically. However, statistical analyses yielded conflicting results. The specimen presented here expands the diversity of vertebrates recorded in Canafístula 01, being another component of the theropod dinosaur fauna from this paleoenvironment of Northeastern Brazil represented by the Feliz Deserto Formation.