Abstract

Thalassodromeus sethi (Pterodactyloidea, Tapejaridae, Thalassodrominae) is a unique pterosaur from the Romualdo Formation, Araripe Basin (Early Cretaceous, Albian). A large sagittal cranial crest (the largest known ossified crest of any pterosaur) and unusual toothless bladed jaws constitute some of its outstanding anatomical features. Its holotype (DGM 1476-R, almost complete skull and mandible in three dimensions) represents one of the largest pterosaur skulls ever found. Here, we provide a detailed osteological redescription of the holotype, which has only been preliminarily described. We also describe and depict for the first time some skeletal regions of Th. sethi, including the occiput, the palatal openings, and a dentary fragment. Finally, in the light of new information concerning this species, we revisited the specimen NMSG SAO 251093 (an incomplete mandible), also from the Romualdo Formation and originally referred to Th. sethi but recently redescribed as a new species of dsungaripterid pterosaur named Banguela oberlii. Here, the analysis of a cast (MN 4703-V) and its inclusion in a phylogenetic analysis recovered NMSG SAO 251093 within the Thalassodrominae, as a sister taxon of Th. sethi and indeed different from it at the species level. We hereby rename it Thalassodromeus oberlii, comb. nov. These considerations provide new data for discussions concerning the morphology of the Tapejaridae, the diversity of the Araripe pterosaur fauna, and the complex evolution of the pterodactyloid palatal region, as well as data for future morphofunctional studies of Thalassodromeus.