Diadema antillarum (black sea urchin) Diadema antillarum (black sea urchin) The black sea urchin, also called a long-spined sea urchin, 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. Animalia, Echinodermata, Echinoidea, Diadematoida, Diadematidae, Diadema, antillarum, reef, coral, algae, grazing, abundance 2015-02-25 image/svg+xml Diadema antillarum (black sea urchin) 2015-02-25 Integration and Application Network https://ian.umces.edu/media-library/diadema-antillarum-black-sea-urchin/ https://ian.umces.edu/media-library/diadema-antillarum-black-sea-urchin/ en-US Animalia, Echinodermata, Echinoidea, Diadematoida, Diadematidae, Diadema, antillarum, reef, coral, algae, grazing, abundance The black sea urchin, also called a long-spined sea urchin, 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.