Convergent evolution among non‐carnivorous, desert‐dwelling theropods as revealed by the dentary of the noasaurid Berthasaura leopoldinae (Cretaceous of Brazil)

Abstract The Cretaceous witnessed the establishment of many desertic landscapes across the globe, including the Early Cretaceous Caiuá palaeodesert, in south‐central Brazil, and those of several Late Cretaceous deposits of the Gobi Desert. Although separated in time and space, their faunas share the presence of medium‐sized, edentulous theropods (e.g. oviraptorids and Berthasaura leopoldinae ) which depart from the typically carnivorous diet of the group. Here, we report a new dentary of the latter taxon, which bears alveolar vestiges, suggesting that its teeth were lost during ontogeny, as previously reported for another noasaurid, Limusaurus inextricabilis , from the Late Jurassic of China. In addition, we used geometric morphometrics to quantitatively analyse the shape of theropod jaw bones, revealing a significant morphological convergence signal for the dentary of Be. leopoldinae and oviraptorids, which are dorsoventrally deep, and bear a large mandibular fenestra. This probably resulted from adaptations to feed on the tough parts of xerophytic plants, which are important food sources in desertic environments.