Caudal Vertebrae

Caudal vertebra are the tail vertebra which are significantly long in the rhamphorhynchoid forms with up to 35 vertebra in some species.  They form a rigid tail structure that would have been used to stabilise the animal in flight.

Dimorphodon has a simple centrum form of vertebra where the dorsal zygopophyses have become extended into fibrous rods, overlapping other vertebral centra.  This arrangement would give the tail a very rigid structure.  Most of the long tailed species would have had a dorsal sail on the end of the tail to act as a rudder in flight.  This soft tissue structure has been preserved in many of the Rhamphorhynchus specimens from the Lithographic Limestone of Bavaria.  It is not preserved in Dimorphodon, where only the bony parts of 2 compete tails are known.

The caudal vertebrae of Rhamphorhynchus show a better developed fibrous extension from the centra. In dorsal aspect, the fibrous rods are in pairs from each vertebra and the longer rods are bifurcated to form two strands (as illustrated by Peter Welnhofer-1973).

Each rod would overlap 5 or 6 vertebra. With about 32 or more rods surrounding each vertebral centrum, the tail would have had a high degree of rigidity.

The caudal vertebrae in the Pterodactyloidea are simple by comparison.  These vertebra are easily confused across other vertebrate species.  It is likely that many pterodactyloid vertebra will have been miss-identified where they have been found in isolation.  They are generally very small.