Pterosaur wing bones
The wing bones of pterosaurs are generally hollow and thin walled. The bone in life was very compact and contained air cavities for lightness of structure. Larger wing bones often had thin cross bracing structures, especially at the ends of the bones.
Occasionally, wing bone fragments are found. They tend to be hollow tubes with a thin hard outer layer and an oval or slightly triangular section. It is unusual to find a complete wing bone on its own.
|The Rhamphorhynchoid Wing
This shows a relatively small humerus and a short wing metacarpal (WMC). The wing phalanges (WP) are quite long in comparison to the rest of the wing bones. There are 4 wing phalanges.
The claws are also on short metacarpals and the ulna is slightly larger than the radius. The section of most of the wing bones at the mid-shaft tends to be oval.
Shown above are two typical sections of the shafts or rhamphorhynchoid wing bones to illustrate the thickness of the bone and the size of the pneumatic cavity. Shapes will vary depending upon the species and the size of the animal.
|The Pterodactyloid Wing
The pterodactyls had a substantial humerus and a sturdy and long ulna. The wing metacarpals (WMC) were significantly much longer than those of the rhamphorhynchoid pterosaurs. The wing phalanges (WP) were a smaller proportion of the overall length of the wing. Most pterodactyloids have 4 wing phalanges.
The claws were well developed and attached to the ends of long metacarpal bones.
The section of typical Pterodactyloid bones shows a very thin wall with a thickening at the angles. The pneumatic cavity is large and pneumatic foramen are slightly larger generally, than in the rhamphorhynchoids.
These characteristics are more accentuated in the larger species.