Description:
The long-spined sea urchin, Diadema antillarum, has extremely long, fragile spines that may measure as much as 4 times the diameter of the test.  Spines are hollow and contain venom which causes a painful sting.  The overall size of long-spined sea urchins may be as much as 20 inches, though test diameter is seldom more than 4 inches.  Typical body color is black, but lighter shades of gray, and even white, are observed.

Habitat:
Long-spined sea urchins prefer quieter waters free from heavy surf.  They are found from the intertidal zone to a depth of approximately 1300 feet;  though are most common in depths shallower than 160 feet.  Typical habitats may include coral reefs, sand or rock bottoms, seagrass meadows having ample turtlegrass (Thalassia testudinum), or mangroves.

Range:
Long-spined sea urchins range from Florida south through the Gulf of Mexico and the Caribbean to Brazil.  They also occur in Bermuda, the Azores, Cape Verdes, and the Canary Islands.