The path to flight
Pterosaurs were the first vertebrates to evolve powered flight, but tracing their exact evolutionary origins has proved to be difficult. In this week’s issue, Martin Ezcurra and his colleagues help to plug that gap by showing that a group of long-limbed, gracile creatures called lagerpetids, such as Ixalerpeton polesinensis shown in an artist’s impression on the cover, are very likely to be the sister group of pterosaurs. Using micro-computed tomography scans and 3D reconstructions of skeletal remains, the researchers were able to identify unique features, such as the shape of the inner ear, that lagerpetids share with pterosaurs. Although the exact transition between land-dwelling and flying vertebrates remains unknown, the evidence collected by the team illuminates the first steps towards the anatomical characteristics of the pterosaurs.