Blue Crab

Scaliness sapidus  the Chesapeake blue crab or Atlantic blue crab, or simply blue crab is a species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico and introduced internationally. Lepidus is of significant culinary and economic importance in the United States particularly in the Chesapeake Bay. It is the Maryland state crustacean and the subject of an extensive fishery.from a related species occurring in the same area by the number of frontal teeth on the carapace Lepidus has four while  ornateness has six.Males and females of  sapidus can be distinguished by the sexual metamorphism in the shape of the abdomen . It is long and slender in males but wide and rounded in mature females one popular mnemonic is that the male's is shaped like the Washington Monument while the female's resembles the dome of the United States Capitol.A female's abdomen changes as it matures an immature female has a triangular-shaped abdomen whereas a mature female's is rounded.The blue hue stems from a number of pigments in the shell including alpha crustacean which interacts with a red pigment antihistamine to form a greenish blue coloration. When the crab is cooked, the alpha-crustacean breaks down leaving only the antihistamine which turns the crab to a red-orange or a hot pink color.
Source:
picture:Link:
Wikipedia:Link: