Bivalve ID??

[Hollie Bird]

Good evening/morning/afternoon everyone. 

 

Today I picked up this partial bivalve and I'm having trouble positively identifying it. Collected from a beach at a site on the North Eastern coast of Northern Ireland, known as Minnis North. Now let me describe the site to you! 

The site comprised of a mudflow involving lower the Jurassic lias, the cretaceous hibernian greensand formation and the Ulster White limestone formation. 

Material from the mudflow has been dumped off the side of an adjacent road at the foot of the landslide and directly onto the beach next to the road. 

It was on this beach I pick up the bivalve in a large pile of jurassic lias mud. 

 

Perhaps it's too battered and incomplete for a positive ID but I'd love to hear your thoughts. :-) 

 

Hollie

[Hollie Bird]

Other side! 

[Thomas.Dodson]

It's a Plagiostoma sp.

[Thomas.Dodson]

Plagiostoma giganteum is apparently common in the Lias and I don't see another Plagiostoma reported there so I guess we have the specific ID.

[Hollie Bird]

Thank you Thomas Dodson. The site is recored as containing both Plagiostoma Rigidum and Plagiostoma Gigantea. 

As to which this I have no idea :-D

[Thomas.Dodson]

5 minutes ago, Hollie Bird said:

Thank you Thomas Dodson. The site is recored as containing both Plagiostoma Rigidum and Plagiostoma Gigantea. 

As to which this I have no idea :-D

Plagiostoma giganteum is still my guess. What reference are you using? I had also read that Plagiostoma rigidum was Oxfordian so if the specimen came from the Lias sediments I would expect P. giganteum.

 

It's a nice specimen since it seems the fine striations are often smoothed over on a lot of specimens.

[Hollie Bird]

I'm finding it a bit difficult to get comprehensive reference materials for this site. The two species of Plagiostoma were mentioned in a report by a local museum. There does seem to be a bit of confusion as to the exact strata represented there as to the nature of the deposits not being insitu. 

This is the first specimen I have seen from local sites containing the fine striations. A keeper. 

[Ludwigia]

I'll go along with P.giganteum.