The fossil record of the genus dates back to the Cretaceous (and maybe the Triassic) (age range: 242.0 to 0.012 million years ago). These fossils have been found all over the world.
References
^ abSerge Gofas (2012). Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O (eds.). "Panopea Ménard, 1807". MolluscaBase. World Register of Marine Species. Retrieved February 21, 2012.