Abstract

Among Pterosauria there are three types of scapulocoracoid construction. In the ornithocheirid scapulocoracoid the scapula is oriented almost horizontally; it is shorter than the coracoid and the glenoid fossa is level with the ventral margin of the vertebral column. In the azhdarchid scapulocoracoid the scapula is curved ventrally and is as long as the coracoid. In this construction the glenoid fossa lies approximately in the mid-horizontal plane of the chest. In the tapejaroid construction, the scapula is about one-third longer than the coracoid, which is oriented subhorizontally, and the glenoid fossa is level with the dorsal rim of the sternal plate. Both latter conditions are hitherto unknown among flying vertebrates and result in an unstable, but manoeuvrable flight, probably powered with wing beats.