Pterosaur endothermy [metabolism]
Discussions by Yann Oliver
Up: Dinosaurs metabolism
The pterosaur Sordes pilosus has left fossils showing a kind of fur on the neck and back (this fur is not homologous to mammal hair), as well as a specimen of Pterodactylus (on the neck). It would then probably have been endothermic, although in the case of pterosaurs the surface of the wings (not known to be covered by hair) could have supplied the heat.
Other very well-preserved pterosaurs do not show evidence for hair. This does not mean that they were automatically ectotherms. Sordes lies almost at the basis of the pterosaur family tree, which shows that endothermy was early present in the pterosaur history, and had no reason to disappear.
Another point is that pterosaurs were capable of active, flapped flight, which requires a big amount of heat.
(Also see the Flying Reptiles.)