The anatomy and diversity of the pterosaurian sternum

Abstract

Despite a key role in anchoring major flight muscle groups, the sternum of pterosaurs has attracted relatively little attention in the scientific literature. Here the sterna of more than 60 pterosaur genera are described and compared. Despite the overall conservative nature of the pterosaurian skeleton, the sternum varies greatly within and between clades, and ontogenetically. The sternum appears to have been mostly cartilaginous in juvenile (flying) pterosaurs, which ossified in different patterns in various taxa and even individuals leading at least in part to the variation seen. Comparisons of the pterosaur sternum to other reptiles suggest that it is formed of the clavicles, interclavicle and sternal plated fused into a single unit, though the details of this remain uncertain. Further studies of this major anatomical feature are required given its importance in anchoring flight muscles and therefore locomotion.