Potamilus ohiensis shell description:

“Shell without the wings, nearly evenly elliptical, a little wider behind with a decided posterior and anterior basal gap, thin, subcompressed, strongly alate, having a very high, triangular posterior wing that is often flexed at the top, and a smaller anterior wing; beaks subcompressed, not high, with a few nodulous, broken, slightly-looped ridges; surface with numerous irregular growth lines and sculptured in fine specimens with delicate radiating lirae, smoky-olive, lighter at the beaks, the rest bands dark, brilliantly polished; left valve with one or two feeble, compressed pseudocardinals and two remote, delicate laterals; right valve with one pseudocardinal, sometimes a faint one above it, and a high, truncated lateral; beak cavities shallow, with an irregular row of shallow scars; adductor scars large and shallow; nacre purplish.  The male and female shells are so near alike that it is often difficult to separate them.  The male shell is generally slightly rhomboid behind and the female is a very little fuller along the base than the male ”(Simpson, 2014; Mather, 2007).