Miocene and Pliocene Pectinidae (Bivalvia) from the Lee Creek Mine and Adjacent Areas

Abstract

Seventeen taxa of Pectinidae (Bivalvia) from lower Miocene to lower Pleistocene strata in the Lee Creek Mine, North Carolina, and surrounding region were studied biometrically. The study of large population samples clarifies the relationships of the taxa and their biostratigraphic utility. Because of widespread geographic distribution of the species into various environmental conditions and relatively short time ranges, the pectens make ideal index species for the outcropping strata. The co-existence of planktonic Foraminifera with the pectinids in some of the strata allows correlation with European stages. Characters found to be most important for discrimination at the subspecific and specific levels include the byssai notch, shape of the resilial insertion, size and shape of the auricles, number and shape of the plicae, and convexity of the valves. One new species, Pecten mclellani, is described from the upper lower Miocene part of the Pungo River Formation exposed at the Lee Creek Mine. It is demonstrated that Chlamys decemnaria (Conrad) from the Pliocene should include C. virginianus (Conrad). A probable intermediate form between Placopecten clintonius of early Pliocene age and the living P. magellanicus is illustrated and described. Other rearrangements at the subspecific level are made. Lectotypes are selected for Pecten yorkensis Conrad, 1867, Pecten eboreus darlingtonensis Dali, 1898, Pecten eboreus urbannaensis Mansfield, 1929, Pecten ( Chlamys) eboreus bertiensis Mansfield, 1937, and Amusium precursor Dali, 1898.