Plesiosaur Vertebrae

Table of Contents

  1. An Overlooked Plesiosaur
  2. Ichthyosaur tooth
  3. A Wonderful Example of a Fossil Fish
  4. Brother and Sister Find Sea-Dragon in Cliffs
  5. Lower Jurassic Leaf
  6. Plesiosaur Vertebrae
  7. Small Ichthyosaur from Blue Lias Ledges
  8. Dapedium from Lang’s Fish Beds Found in May 2008 Landslip
  9. The Beast in the Cellar

Plesiosaur vertabra

A little while ago, Museum Geologist Paddy Howe found a juvenile plesiosaur with a neck deformity. This specimen now belongs to the museum and it is soon going to be mounted and put on permanent display. It has been on temporary display in the ground floor gallery for some time. On 19th May 2011 Paddy and Museum Education Officer, Chris Andrew went out fossil hunting on the ledges at low tide. Paddy found another vertebra (see right), presumably from the same plesiosaur. This has now reunited with the rest of the animal. It is almost certain that it is from the same animal for several reasons. Firstly it was in the same area as the original find, secondly it is from a juvenile animal. This is known because the neural arch has not fused to the centrum. The method of preservation is also consistent with both the newly found bone and the original skeleton showing very little crushing and being very dark in colour. As plesiosaurs are so rare it would be extremely unlikely that it is from a different juvenile animal. The new vertebra centrum is from the base of the animals neck. You can tell this by the facets on the side of the centrum where the ribs attached. Lower Jurassic plesiosaurs have double headed ribs on their necks (see below).

The new vertebra must have been eroded out of the shale before Paddy found the skeleton. It has spent the time since rolling around on the ledges among the seaweed.

The final picture is not of a local fossil find. It is a plesiosaur dorsal (main body vertebra) from Gloucestershire. It shows the parts described above. The main round disc of the vertebra is the centrum. The higher part goes over the top and is called the neural arch. It protects the spinal chord and provides an attachment for muscles. You can see the hole where the spinal chord passed through. This is from an adult animal so the two parts have fused together.

The four pictures below show the juvenile plesiosaur to which the vertebra belonged. The first is the “full” skeleton, followed by the caudal vertebrae, the pectoral girdle and a rear paddle. All are shown during the reconstruction process that followed the find.