Sea urchin

''Diadema antillarum'', also known as the lime urchin, black sea urchin or the long-spined sea urchin, is a species of sea urchin in the Family Diadematidae.

This sea urchin is characterized by its exceptionally long black spines.

It is the most abundant and important herbivore on the coral reefs of the western Atlantic and Caribbean basin. When the population of these sea urchins is at a healthy level, they are the main grazers which prevent algae overgrowth of the reef.