They 1st appeared during the Triassic period. Until recently, most scientist would not have put pterossaurs in the same class as birds in terms of flying ability. It is very difficult to say how pterosaurs changed over time because the earliest fossils we have are of pterosaurs whose forth finger has already turn into a wing, says Fabic dalla vecchia, an italian researcher. But how pterosaurs learnt to fly remains a matter for disagreement. most researchers conclude that pterosaurs are descended from a small tree dwelling reptile that spent its life jumping between branches.
The triumphant reign of pterosaurs ended with the giant flier. At the end of the Cretaceous period 65 million years ago, a meteorite or comet slammed into the earth. Pterosaurs flew into sunny skies before any other vertebrate, For 150 million years they sailed the winds on the strength of a fragile finger. What a glorious ride they had