Flight characteristics of Triassic and Jurassic Pterosauria: an appraisal based on wing shape

Abstract

The mass, wingspan, and wing area of pterosaurs were reconstructed. Mass was estimated by determining volume and multiplying by avian density. This method was considered appropriate only for smaller pterosaur species because there is evidence for lower density in larger species. These reconstructions were used to compare the wing shapes of Triassic and Jurassic pterosaurs with those of birds. Pterosaurs had wings of below-average loading and above-average aspect compared to the avian mean. This wing design was compatible with relatively slow and highly efficient flight, with high maneuverability. Wing area depends on the reconstruction model adopted; wings attached to the hindlimb principally reduced aspect, and secondarily reduced loading, which would improve take-off performance at the expense of efficiency. The wing shape and cranial feeding adaptations of pterosaurs were most compatible with a marine or aerial predatory adaptive zone. The reconstructed pterosaurs show a limited range of wing shape compared to birds. This may partly reflect preservational bias favoring species living in marine or lagoonal environments, but this is not a complete explanation because there is a lack of pterosaurs with wings of high loading like the marine ducks and auks. Structural, physiological, or adaptive factors may have limited pterosaur wing shape.