Marine Animal Encyclopedia
Atlantic Thorny Oyster Spondylus americanus
The Atlantic thorny oyster’s spiny shell protects it from predators. The oyster pictured here is covered with an encrusting red sponge, which provides camouflage. This species is unusual in having a ball-and-socket type hinge joining the two halves of its shell, rather than the more common toothed hinge seen in many other bivalves. The Atlantic thorny oyster cements itself directly to rocks rather than using byssal threads.