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Monday, 30 May 2011

Plesiosaur detective work

Earlier in May, the Museum Geologist Paddy Howe found this fossil amongst the pools and seaweed on the blue lias ledges to the east of Lyme Regis.

Firstly, what is it? Well, its easily recognisable (at least by Paddy) as a plesiosaur vertebra. It would certainly take pride of place in my collection but Paddy is far more interested in more complete plesiosaur specimens than this. Where there is a vertebra, might there be a larger specimen?

Paddy found an excellent specimen of a juvenile plesiosaur on these ledges a few months ago. Is this from the same specimen or is it worth spending time hunting for a new specimen? If it is from the same plesiosaur then the vertebra must have been released from the rock before Paddy found the plesiosaur and have been washing around in the sea since then until Paddy (coincidentally) found it.

So what evidence have we got? We only have the shape, size, colour and texture of the vertebra but this is enough! The shape and size indicate that the vertebra is from a juvenile plesiosaur. The colour and texture are indications of when, where and how it was fossilised. These match the plesiosaur that Paddy had found earlier and so he concluded that the vertebra was from that specimen.

If you would like to know how Paddy knew the vertebra was from a juvenile plesiosaur or see pictures of the "full" specimen then click here.

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