Broadly fan-shaped, auricles subequal, moderately inflated with right valve slightly more convex, solid, left valve cream with chestnut brown mottlings and opaque white specks, right valve lighter colored, with ca. 20 squared radial ribs, interspaces with fine commarginal threads, posterior auricle with 4-6 ribs; interior white flushed with yellow. Florida, Bahamas, West Indies, Gulf of Mexico, South America (to Suriname). Length 17 mm (to 45 mm). Compare other Argopecten species; A gibbus is usually pink or orange mottled, whereas A. irradians is more evenly brown to gray.