Chesapecten nefrens.1

Wow, that is an A++++ find! It's humongous, both halves are in great shape, and has great color preservation to boot.

And it looks 100% like C. nefrens.

But the weird thing is C. nefrens is an old school Chesapecten from the middle Miocene, you wouldn't find it or anything like it in Pliocene deposits. The Pliocene Chesapectens for the most part didn't have that "funny long ear" (left auricle of top figured specimen) which is characteristic of the main Miocene Chesapectens. I read somewhere that the Pliocene scallops lost that funny ear bc they spent more time evading predators than relaxing on the seabed. Link here in case you're interested: http://publish.wm.edu/cgi/viewcontent.cgi?article=1438&context=honorstheses

How sure are you that this was pulled from a Pliocene exposure?

Anyways congrats on the find!!