Large Jurassic bivalve ID

[Aurelius]

Please can anyone identify this shell, from the Jurassic of Somerset, UK? It's a biggie. Sorry the photos aren't ideal.

 

[Fossildude19]

@TqB   @Tidgy's Dad

[Tidgy's Dad]

Could be something like Plagiostoma giganteum, I suppose. 

Looks Lias. 

Somerset is quite a big place, full of fossil localities. I know 'cos I was born and raised there. 

Can you be a little more specific with the locality if possible, please ? 

[TqB]

I think it is a Plagiostoma giganteum (or gigantea, but the NHM goes with -eum),  but we're not seeing a full on valve. The flat, inward facing facet at the edge of one side is typical.

Edited January 16, 2021 by TqB

[Tidgy's Dad]

1 hour ago, TqB said:

I think it is a Plagiostoma giganteum (or gigantea, but the NHM goes with -eum),  but we're not seeing a full on valve. The flat, inward facing facet at the edge of one side is typical.

Tarquin, old chap. 

[Ludwigia]

Can we please have a third view from the underside? I'm also thinking the same as Tarquin and Adam, but I could also see Gervillella as a possibility.

[TqB]

1 hour ago, Tidgy's Dad said:

Tarquin, old chap. 

And to you, Adam! 

[Aurelius]

51 minutes ago, Ludwigia said:

Can we please have a third view from the underside? I'm also thinking the same as Tarquin and Adam, but I could also see Gervillella as a possibility.

 

Sure, here's the underside, though I don't know how much help it'll be (I'm guessing very little). 

 

I also include a different angle.

[Aurelius]

6 hours ago, Tidgy's Dad said:

Could be something like Plagiostoma giganteum, I suppose. 

Looks Lias. 

Somerset is quite a big place, full of fossil localities. I know 'cos I was born and raised there. 

Can you be a little more specific with the locality if possible, please ? 

 

It was Lias, from Watchet.

[Ludwigia]

Thanks for the last 2 shots. That's cleared it up for me. Plagiostoma giganteum (or gigantea). No one seems to know for sure what the correct name is.

[Thomas.Dodson]

3 hours ago, Aurelius said:

 

Sure, here's the underside, though I don't know how much help it'll be (I'm guessing very little). 

 

I also include a different angle.

Actually those pictures help a lot. Like others have said this is Plagiostoma giganteum.

[Tidgy's Dad]

12 hours ago, Aurelius said:

 

It was Lias, from Watchet.

Ah, yes, I was born in Bridgwater only a few miles away. 

This would help confirm the id for me.