Pterosaurs are noted for having very lightly boned skull structures. The skull is of a type called Diapsid, as it always has two pairs of openings at the back of the skull. The skull bones have sutures binding them together and as the animal matures, some of the suture joints become fused and difficult to distinguish. The mandible in pterosaurs is composed of 3 bones on each side. At the orbit there is a sclerotic ring of bones to offer support and protection to the eye, which is not always preserved in the fossil skulls.
Dimorphodon (above) and Dorygnathus (below) skull bones;
Angular; ar Articular; d Dentry; f Frontal; j Jugal;
l Lacrimal; m Maxilla; n
Nasal; or Orbit;
p Parietal; pf Postfrontal; pm Premaxilla; prf Prefrontal; q Quadrate; qj Quadratojugal;
sa Surangular; so Supraorbital; sq Squamosal: