Tales of Tolgard
The anatomy of pterosaurs is highly modified from their reptilian ancestors for the demands of flight. Pterosaur bones are hollow and air filled, like the bones of birds. These dinosaurs have a keeled breastbone that was developed for the attachment of flight muscles and an enlarged brain that shows specialized features associated with flight.
Pterosaur wings were formed by membranes of skin and other tissues, strengthened by various types of closely spaced fibers called actinofibrillae. The membranes attached to the extremely long fourth finger of each arm and extended along the sides of the body. A bone unique to pterosaurs, known as the pteroid, connected to the wrist and helped to support a membrane (the propatagium) between the wrist and shoulder.