Ensitellops species (single valve)

    The shape of this little white clam (LWC) bears an uncanny resemblance to the lasaeid Erycina periscopiana Dall, 1899, but the unambiguous single cardinal and divaricate external sculpture in this R valve place it firmly in the sportellid genus Ensitellops Olsson and Harbison, 1953. There are four (4) Carolinian Province congeners in the Lee Collection, including the type [En. protexta (Conrad, 1841)] and an un-named one. This resource notwithstanding,  the illustrated specimen matches none of  the shells in a dozen lots. Furthermore, elsewhere therein is a R valve of Er. periscopiana, while resembling this shell in silhouette, has an utterly different hinge structure, without a true cardinal - just like the figure in Abbott (1974: 468; sp. 5404). This is a remarkable example of conchological convergence between LWC species in separate families.

Abbott, R. T., 1974. American seashells. Second edition. Van Nostrand Reinhold Co., New York, pp. 1-663 incl. numerous text figs. + 24 pls.

Ensitellops species (single valve)

Caswell Beach, North Carolina. Digital images by David Kirsh.