The tail vertebrae at the base, the authenticity of which is certain, are short.
Another partial skeleton, including four more tail vertebrae and material from both limbs on the left side of the body, was described in 1997.
It consists of a complete skeleton, possibly only missing a few tail vertebrae.
The broken and displaced 16th tail vertebrae has a pit which may be from a bite wound.
Four additional tail vertebrae have been assigned to it.
The fossil has preserved just nine tail vertebrae; likely fifty or more had been originally present.
It has, however, unique joints in the tail vertebrae which account for its unusual name.
In early mosasaurs, the tail vertebrae were more or less the same and unspecialized.
The most serious pathology discovered was in a series of five large tail vertebrae.
However, as Carpenter has noted, the plates overlap so many tail vertebrae that movement would be limited.