Pterosaur Skull Forms

Rhamphorhynchoids - which have long tails and small wing metacarpal bones.  These are the earliest types of pterosaurs

Pterodactyloids - which have short tails and long wing metacarpal bones.  These pterosaurs eventually evolved into the largest flying animals ever known on Earth.

Rhamphorhynchoid Wing Form

Pterodactyloid Wing Form

These diagrams show how the earlier Rhamphorhynchoid pterosaurs had shorter wing metacarpals (WMC) and a longer wing finger (WP).  In the later Pterodactyloid pterosaurs, the longer wing metacarpals allow for more muscle power within the wing and this would have been more efficient and better to control in flight.