Shell of the Week: The Concentric Ervilia
Measuring 5.5 mm (0.22 inch) at most, Ervilia concentrica (Holmes, 1860) is one of the smallest bivalves found on our barrier islands beaches. The species belongs in the same family (Semelidae) as its more famous (and larger) cousins, the Purplish Semele and the Atlantic Semele. The shell is elongate, with the umbo (or beak) situated almost centrally, and its sculpture consists of very fine commarginal (concentric) ridges. The prevailing color in this species is a light pink, but whitish varietals are not unheard of. The shell in the photo was collected by Susan J. Hewitt at Blind Pass on Captiva, in December 2014.