Atlas Obscura has an article about pterosaurs. Good background information and a discussion of a paper in the Proceedings of the Royal Society B. It seems someone(s), Armita R Manafzadeh and Kevin Padian, mapped the ligament constraints on hip mobility of extinct ornithodirans (pterosaurs). It seems that it is very unlikely that pterosaurs flew with they legs stretched out behind them. Check out the paper or more details.
PICTURE A CLASSIC CRETACEOUS SCENE. Sure, you’re a bit too late to have caught it in person, but if you’ve seen a kid’s book lately, you know the one. Broad-leafed plants cover the landscape. Triceratops graze, and velociraptors sneak around. Above everything flaps a flock of pterosaurs, their wings spread wide and their legs akimbo.
It’s a nice view. But according to a new paper in Proceedings of the Royal Society B, at least one detail is almost certainly off: Pterosaur legs simply didn’t bend that way. By pinpointing the range of motion of more contemporary animals, researchers have narrowed down how flexible these prehistoric flyers were, and weren’t.
When the first pterosaurs were found, in Bavaria in the late 1700s and early 1800s, “people thought they were reptilian bats,” says Armita Manafzadeh, a Ph.D. student at Brown University and the paper’s lead author. “The first drawings of them that came out, both scientifically and to the public, were extremely bat-like.”