Atlantic Thorny Oyster

Atlantic thorny oyster, Spondylus americanus, is a species of bivalve mollusk of the family Spondylidae found along the Atlantic coast of North America, ranging from North Carolina south to Brazil. Its heavy, irregularly shaped shell is studded with long, spine-like projections that give the genus its common name, and it cements itself permanently to hard substrate such as rock or coral rather than moving freely like many other bivalves.