The Pterodactyloids-Page 2

There were also modifications to the bones in the flight apparatus: the scapula was attached directly to fused vertebrae. This combination of a fused backbone and rigid attachment of the scapula provided a rigid and extremely strong brace that could resist the stresses associated with flapping of wings.

In order to better control their wings, the wrist bones were fused into two rows. There were modifications to the bones which made up the fingers (metacarpals and phalanges). In Rhamphorhynchoids the phalanges were more elongated than metacarpals; in Pterodactyloids this was reversed. The metacarpals became more elongated than the phalanges. This had the advantage of distributing the wing membrane over the stronger metacarpal bones.

It could be supposed that the reason for these modifications is that Pterodactyloids grew to be much larger than the Rhamphorhynchoids. In order to reduce weight, they lost the tail which is replaced by having greater control over the wings, and strengthened the rigidity of the flight apparatus.

Examples of Pterodactyloids
1) Pterodaustro
2) Dsungaripterus
3) Quetzalcoatlus
4) Pteranodon

© Patrick Lyons 1998.