New reptile shows dinosaurs and pterosaurs evolved among diverse precursors

Abstract

Dinosaurs and pterosaurs have remarkable diversity and disparity through most ofthe Mesozoic Era1–3. Soon after their origins, these reptiles diversified into a numberof long-lived lineages, evolved unprecedented ecologies (for example, flying, largeherbivorous forms) and spread across Pangaea4,5. Recent discoveries of dinosaurand pterosaur precursors6–10 demonstrated that these animals were also specioseand widespread, but those precursors have few if any well-preserved skulls, handsand associated skeletons11,12. Here we present a well-preserved partial skeleton(Upper Triassic, Brazil) of the new lagerpetid Venetoraptor gassenae gen. et sp. nov.that offers a more comprehensive look into the skull and ecology of one of theseprecursors. Its skull has a sharp, raptorial-like beak, preceding that of dinosaurs byaround 80 million years, and a large hand with long, trenchant claws that firmlyestablishes the loss of obligatory quadrupedalism in these precursor lineages.Combining anatomical information of the new species with other dinosaur andpterosaur precursors shows that morphological disparity of precursors resemblesthat of Triassic pterosaurs and exceeds that of Triassic dinosaurs. Thus, the ‘success’of pterosaurs and dinosaurs was a result of differential survival among a broaderpool of ecomorphological variation. Our results show that the morphologicaldiversity of ornithodirans started to flourish among early-diverging lineages andnot only after the origins of dinosaurs and pterosaurs.