Ichthyosaurus communis Premaxilla?

[Westralian Fossils]

Just bought a small ichthyosaur bone block from Lyme Regis. The seller has said that the block is from an Ichthyosaurus communis and was found at Church Cliff Bay. I’ve been looking at some diagrams of ichthyosaur skull cross sections and one of the bones resembles a premaxilla. It’s about 5 cm long. B II in the diagram. Just wondering if this is the case before I get to  prepping it so I have some idea of what I’m working with .

[Welsh Wizard]

Hi

 

It’s a collection of ichthyosaur vertebrae in pyrite, along with some neural arches. You are looking at one of the neurals sliced vertically in section. That’s the bone like a Y.

 

Nick

[TqB]

I agree with Nick, neural arch.

[fossils-uk]

Neural arch. And you said your going to try prepping through that pyrite - yeah good luck with that. 

[pachy-pleuro-whatnot-odon]

2 hours ago, fossils-uk said:

Neural arch. And you said your going to try prepping through that pyrite - yeah good luck with that. 

 

The pyrite isn't just impossible to prep through, but it also has a tendency to decay, is what Byron means. The best thing for you to do is just leave it as it is, as bone is often softer than the surrounding matrix, with pyrite - an iron compound - being especially hard to work through, and then just hope the pyrite won't start to disintegrate from what's known as "pyrite disease".