Uncommon in the Solitary Islands Marine Park. Found throughout the Tropical Western Pacific, Red Sea, South Africa. In Australia from Exmouth in Western Australia, across the tropical north to northern New South Wales on the east coast.
Frequents coral habitat in shallow reef. Depth to 90 m.
Longer spines are pale in colour and interspersed with shorter, sharper dark spines. Darker coloured faecal sac with white spots. Spines in earlier growth stages have blunt tips and banding, see lower photograph. Grows to about 220 mm diameter.
Neville Coleman, Sea Stars. Echinoderms of the Asia/Indo-Pacific. Neville Coleman's Underwater Geographic Pty Ltd, 2007. p.91.
Atlas of Living Australia website at https://bie.ala.org.au/search?q=Echinothrix+calamaris. Accessed 10/10/2018.
Identification thanks to Ashley Miskelly, Echinoid Taxonomist, The Sea Urchin Science Centre and Gallery, Kurrajong, NSW.