Chondrocidaris gigantea

Chondrocidaris gigantea grows to between 20 and 25 cm (8 and 10 in) in diameter,^[2] with each of its spines reaching 15 cm (6 in) in length.^[2] Its spines contain thorns, allowing for the growth of algae and sponges.^[4] In turn, the algae and sponges that grow provide camouflage for the sea urchin.^[4] The amount of spines found on this species can vary depending on region, for example those found in Mauritius only have 5 spines while those in Hawaii may have up to 10.^[5] The rough-spined sea urchin is primarily an herbivore, with most of its diet consisting of the algae that form on the coral reefs.^[2]

The rough-spined sea urchin can be found in the Central Pacific, including Hawaii, New Guinea and French Polynesia, as well as in Mauritius.^[6][7] It prefers coral reefs in water depths deeper than 150 ft (46 m).^[3] using the surrounding coral as cover.^[4]