Pterosaur Vertebra

Vertebrae of small pterosaurs are seldom found in isolation.  This may be that they are often too small and fragile to be preserved individually.  The vertebrae of large pterosaurs do survive and are rare. Pteranodon and Ornithocheirus show the largest numbers of individual vertebrae (though identification is uncertain in many cases).

Groups of vertebra are easier to identify - comparison with type material is essential for accurate identification.  The problem is one of convergence.  Vertebrae need to be a certain shape to function effectively, so most pterosaurs have very similar vertebral structures.

Atlas / Axis The bones that join the spinal column to the neck.  Some large pterosaurs have these bones fused into a single axis vertebrae.
Cervical Vertebrae These are the vertebrae that are more likely to be different, depending upon neck size and function.  Some worn cervical vertebrae look like caudal (tail) vertebrae so take care.
Notarium This is a fused region around the rib cage where the bones supporting the wings are attached.  It comprises most or all of the thoracic vertebrae.
Thoracic Vertebrae In some species there are a few thoracic vertebrae that are un-fused.  These tend to be behind the notarium.
Lumbar Vertebrae These are the few vertebrae between the notarium and the synsacrum.  Pterosaurs (like birds) had very inflexible backs and this region is the only place where limited flexing could occur.
Synsacrum The region where the pelvis and leg bones attach.  The bones in this region are fused.
Tail In rhamphorhynchoids, this is a long series of interlocking vertebrae with strong ligaments holding the tail rigid.  In pterodactyloids it is a short structure which was more flexible.

 

 

Cervical vertebrae of an Ornithosaur, Cambridge Greensand.

This is a first cervical vertebra (axis) showing the dorsal crest.  In life, these bones were pneumatic - being filled with air to make them light, but strong.

Crushed cervical vertebrae of a pteranodontid pterosaur.

These fragile bones are often preserved in a distorted state, collapsing during the fossilisation process.
 

Another typical vertebrae from a large pterosaur - showing the collapsed structure.  These bones are distorted to such an extent that two adjacent bones cannot be fitted together.
Sometimes a group of vertebrae may be found in situ and undistorted.  These cervical vertebrae from an Ornithosaur came from the Cambridge Greensand.
 

Vertebrae and ribs from a Rhamphorhynchus.

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