Here is a picture of a Parvamussium cristatellum (Dautzenberg & Bavay, 1912) bivalve fossil at the Museo di Paleontologia at Sapienza University of Rome Italy. Creatures like this existed in the Miocene Epoch of Neogene Period. At the museum it was labeled as Amussium cristatum aka Pecten cristatum (Bavay, 1905).
Image taken in June 2014.
Info Sources:
http://www.marinespecies.org/aphia.php?p=taxdetails&id=215410
http://www.marinespecies.org/aphia.php?p=taxdetails&id=394473
http://www.gbif.org/species/4374335
http://www.lusofossils.com/biva.html