Rough Scallop

Shell size to 33 mm; shell equivalve, valves convex, hinge with wing-like projections of unequal size. Surface sculpture of 18 to 20 ribs, each with three rows of sharp scales. Color reddish-brown, orange, rarely lemon-yellow. In February 2010, individuals of this species were found on the east end of Sanibel Island covered (both valves) with the sponge Myxilla incrustans (Esper, 1905) (see photos.)