Kingdom: Animalia
Phylum: Echinodermata
Class: Echinoidea
Order: Diadematoida
Family: Diadematidae

Genus/species: Diadema setosum

GENERAL CHARACTERISTICS:  Usually black but some or all of them can be grey or white. Very long, black spines are up to 30 cm (1.1 inches). Orange-red ring around anal cone at the center of its dorsal surface is distinctive. Weight 35 gm (1.25 oz) to 80 gm (2.8 oz).  Adult test to 9 cm (3.5 inches) diameter with a distinct pattern of iridophores, usually with 5 white dots.  Height to around 40 mm (1.5 inches) high. 


DISTRIBUTION/HABITAT: Red Sea, east Africa to western Pacific (Philippines) in low tide areas to 20 m (66 ft) on rubble and seagrasses. Often abundant in shallow water areas that have been recently disturbed. Also in lagoons and on coral and rocky reefs.


DIET IN THE WILD: Herbivore. Hides during the day, and emerges at night to feed on algae, plankton, and waste material. Its feeding habits help keep the reef free from coral-smothering algae; however, too many of these algal-eating machines can actually threaten a reef, scraping away living coral as they devour algae and leaving little food for other herbivores.

CONSERVATION: IUCN Red List ; not evaluated.

REMARKS: Uses hundreds of flexible, tube feet to move around, eat and breathe.

The venom is mild and causes swelling and pain, and gradually diffuses over several hours. Tiny hooked barbs often require surgical removal.

Commensal with a number of species, including various shrimps and fishes.


Sea-grass shallows PR03a


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