The first pterosaur from the Bauru Group: an azhdarchid from the Upper Cretaceous of Brazil

Abstract

The vertebrate fossil record of the Bauru Group (Upper Cretaceous, southeastern Brazil) is remarkably rich, with a predominance of titanosaurs and crocodyliforms, alongside theropods, turtles, squamates, fishes and even small mammals. In contrast, pterosaur remains from the Bauru Group have remained elusive until now. Here, we describe a fragmentary jaw from the upper Maastrichtian Serra da Galga Formation, representing the first confirmed pterosaur discovery from the Bauru Group. The specimen was collected in the Serra da Galga Geosite and is interpreted as a rostrum (upper jaw tip), showing diagnostic features that support its identification as a new azhdarchid species: Galgadraco zephyrius gen. et sp. nov. This new taxon represents the first Brazilian azhdarchid and bears striking similarities to the coeval Albadraco tharmisensis from the Haţeg Basin, Romania. Phylogenetic analysis recovered Galgadraco as a sister taxon to Albadraco, both deeply nested within the clade Quetzalcoatlida. Additional indeterminate pterosaur fragments were also recovered from the same level of the fossil site and include another jaw fragment, a diminutive (?hatchling) lower jaw with azhdarchid affinities, a distal metacarpal IV, and ungual fragments. This highlights a previously unrecognized archosaurian diversity, with important implications for the palaeoecology of the Serra da Galga Formation.