unusual brachiopod/bivalve found at Runswick Bay 21.10.12 can anyone identify?

I have had no luck so far, I shall not give up though

the underside mostly showing the fracture from the substrate

and another top view

The structure looks very out off place , almost seed like.

but i trace the join of the valves thus

Ok - I have an answer.

I sent the pictures to Dean Lomax, Author of Fossils of the Whiby Coast and one of our experts at Saltwick bay on the saturday.

This is from Dean:
"What a nice little find, this is a species of the bivalve Pholadomya sp. This a rather variable genus with many species, probably one of those genera which needs a severe revision. Nonetheless, there is another Pholadomya in the Whitby coast book see page 49, but this is a different species. The one you are looking at appears to have the double valve and are often termed 'heart-shaped cockles'."


Heres a similar example from the middle jurassic I have found online

Source: http://www.geologischevereniging.nl/werkgroepen/themas/fossielen/fos97.htm

Nice piece of detective work

Vik

In times of need, ask Palaeontologist.. Happens rather too often here at uni.. I didn't know where to start on this one though..