The Ptesosaurs: Not just a gliding motion
Some recent findings have required some radical changes to our thinking on the pterosaurs. Some Soviet scientists have reported that one of the smaller pterosaurs (Sordes pilosus) had fur like mammals; implying that they were endothermic. Recent analysis of pterosaurSandactylus (5 metre wingspan) the skin of the pterosaur wing was quite thick, with epidermal, dermal and muscle fibre layers, and therefore not just a membrane. Within the upper dermal layer were blood vessels. This anatomy and arrangement of blood vessels is similar to that of a bats wing which uses its blood vessels to cool itself while flying. If the pterosaur needed to cool down, the flying must have involved energy expenditure, and therefore be active (flapping) rather than gliding flight. The lack of stiffness in the pterosaur wing is difficult to interpret if they flapped their wings. It is, however, hypothesized that Sandactylus kept its wings at a constant tension by moving its hind legs, which were also attached to the wing. The implications of these findings are that pterosaurs had more control over their flight than scientists had previously thought, and that their flight was not limited to passive gliding. These pterosaurs were obviously fascinating animals which dominated the skies for 100 million years, unfortunately they left no descendants for us to study.
"Flying by wires, a model Pteranodon longiceps takes to the air over western Kansas. Remains of the species were found in the Niobrara chalk, laid down about 85 million years ago on the floor of a broad seaway that covered much of mid-continental North America. Fossils found in such marine deposits prove that some pterosaurs were strong long-distance aviators." http://www.nationalgeographic.com/ngm/0105/feature5/zoom2.html