Lampsilis rafinesqueana shell description:

Very similar in appearance to Actinonaias ligamentina and often confused with it. “Shell oblong, dorsal line gently rounded, ventral line straight to gently curved; anterior end uniformly rounded, posterior end truncated above and at the posterior ridge which usually gives it a biangulate appearance.  Shell is strong although relatively thin; size to 9.5cm; compressed; posterior ridge broadly rounded dorsally becoming flattened and biangulate ventrally.  Beaks low, only slightly raised above the hinge line;  inequipartite; beak sculpture consists of a number of fine lines rounded up posteriorly; growth-rest lines prominent; the epidermis is usually darker colored in the grooves.  Epidermis light brown and has a dull, waxy luster; it usually becomes dark brown with age; green rays usually cover the surface, rays are often discontinuous, especially during the second and third year of growth; during this period the shell usually exhibits chevron- and Y-shaped patterns. Left valve has two stout, divergent, striated, triangular pseudocardinal teeth; the two lateral teeth are short, stout and slightly curved.  Right valve has a tall, triangular to columnar, striated pseudocardinal; a low, lamellar tooth can be seen anteriorly; right lateral tooth is short, stout and slightly curved.  Interdentum present but not broad; beak cavities relatively shallow; nacre bluish-white to white, slightly iridescent posteriorly” (Mather 2007).