Stone crabs have exoskeletons and have a brown and black speckled carapace that is oval, smooth, and convex. The carapace averages 130 mm across in adult females and 145 mm across in adult males. Adult Florida stone crabs have a trunk composed of 14 segments, and 5 pairs of stout walking legs, which have reddish and yellow bands and distal hairs. The first eight segments compose the thorax, and the remaining six segments compose the abdomen. The first set of walking legs develop into an asymmetrical pair of heavy chelipeds that typically make-up 60% of the animal's entire body weight and possess a crushing pressure of 14,000 pounds per square inch.
Juveniles are a dark purplish blue. Younger juveniles have a white spot on the carpus, which is the middle segment of the endopod, or limb.
Average length: 0.079 m.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: male larger