Monday, 3 January 2011

Pliosaur Vertebra - Some Facts & Figures

Note the nutritive foramen.
One of my correspondents, Paul, has shown some interest in this pliosaur vertebra and rightly so. It is extremely rare to find a vertebra this well preserved and uncrushed from the Oxford Clay. It seems to be from either Simolestes or Liopleurodon although, due to its size, we feel that it is almost certainly Liopleurodon since the same area has produced a few big Liopleurodon teeth toward the back end of 2010. There may be more material to collect but it is all underwater at the moment and inaccessible.

The centrum is 85mm long in a straight line and extremely concave. Both cranial and caudal articular surfaces are almost circular and slightly convex, 100mm in length mediolaterally and 110mm dorsoventrally on the cranial face and less caudally although this surface has suffered some damage. Ventrally there is a keel and there is one foramen exposed on the right lateral side of the centrum about 35mm up from the aforementioned keel. The other foramen is below the attached rib? on the left lateral surface.

Another pointer to Liopleurodon is the fact that connecting area between centrum and neural arch is extremely long - almost the whole length of the centrum. The processes themselves I've kept plugged with matrix while I've been prepping the centrum - for added support. But it is evident that both neural spine and the transverse processes were thick and robust. The overall height of the vertebra from keel to the uppermost neural process is 210mm.

Preparation has been fairly straight forward although I have spent quite a bit of time on the right lateral side of the centrum carefully teasing off matrix off what is left of the surface patina of the bone. The processes represent quite a challenge but the neural canal is there and intact. I'll keep you informed as the vertebra develops.

In cranial view.

In caudal view.

The float may be rib or process - not too sure just now.

2 comments:

saurian said...

I neglected to mention that this vertebra weighs 1.9 Kg.

Anonymous said...

Hello Saurian, I have 2 verts, probably from Stewarby if you're interested (Pliosaur).
01582 515440
Colin

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