Long-spined Sea Urchin

Diadema antillarum, also known as the lime urchin, black sea urchin, Grabaskey's bane or the long-spined sea urchin, is a species of sea urchin in the FamilyDiadematidae.
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.
== Description ==
iadema antillarum has a test, or "shell," similar to most other sea urchins. What distinguishes the Diadema is the length of its spines. Most sea urchin spines are 1–3 cm, but the spines in this species are usually 10–12 cm in length, and can grow as long as 30 cm in very large individuals.
Diadema antillarum is still, in some tropical areas, one of the most abundant, widespread, and ecologically-important shallow-water sea urchins. It is found in the tropical Western Atlantic Ocean, including the Caribbean Sea, Gulf of Mexico and the northern and eastern coasts of South America (as far south as Brazil). It is also found in the East Atlantic at the Canary Islands. This species is ecologically important because it consumes algae that can otherwise grow to such an extent that they can smother coral reefs. They live in holes that are in the reef.
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