List three features of S. crassirotris' skeleton that imply that the animal was adapted to flying.

The mechanics of pterosaur flight are not completely understood or modeled at this time. however, many evidences seems to prove that they were very capable fliers.
Pterosaur bones were hollow and air-filled, like the bones of birds. They had a keeled breastbone that was developed for the attachment of flight muscles and an enlarged brain that shows specialised features associated with flight. In some later pterosaurs, the backbone over the shoulders fused into a structure known as a notarium, which served to stiffen the torso during flight, and provide a stable support for the scapula (shoulder blade).