Potamilus leptodon shell description:

“Shell irregularly long ovate, the dorsal line being generally more nearly straight than the basal line, very inequilateral, thin to subsolid, rather compressed, with a low narrowly rounded posterior ridge, slightly winged behind when young, the wing mostly disappearing in adult shells, gaping at the anterior base and behind; beaks low, rather compressed, their sculpture consisting of a few very faint, doubly-looped ridges; surface covered with wide, very uneven, often sulcate, growth lines, greenish, olive-green, or in old shells brownish, with wide, feeble green rays; epidermis not shining; there is a very feeble, low tubercle under or in front of the beaks in each valve, but it is sometimes wholly wanting; left valve with the faintest vestige of one or two remote laterals; right valve with a stronger single lateral; beak cavities shallow with a row of irregular, large dorsal scars; anterior adductors long, vertical; posterior adductors large; nacre purple, bluish or salmon-color, often clouded.  The male and female differ but little;  those of the latter have a slightly fuller base, and the rather sharp posterior point is a little higher than in that of the male”(Simpson, 2014; Mather, 2007).