I didn't cite a causative link between wing structure and size. There were plenty of small pterosaurs. I cited a causative link between wing structure and par

I didn't cite a causative link between wing structure and size. There were plenty of small pterosaurs. I cited a causative link between wing structure and parenting demands. And that is tied to the fact that babies can't fly if their wings don't support it. I have no idea from which article I ran across the connection between wing structure and juvenile flight. But the idea stuck because I was familiar with heterochrony from having read too much Stephen J. Gould when I was younger. However it is an observable fact that baby bats and birds do not fly, while fossil evidence says that pterosaurs did. The amount of parenting effort that birds require is also well-documented.