Common Name: Eleven-armed Seastar

Distribution: Uncommon in the Solitary Islands Marine Park. Known from temperate waters surrounding southern Australia, from Houtman Abrolhos on the west Australian coast and southern Queensland on the east coast. Also around Tasmania and abundant in Port Phillip Bay in Victoria.

Ecological Notes: Benthic species frequenting temperate waters inshore to the Continental Shelf. Known from depths to at least 150 m.

Additional Notes: The largest species of seastar found in southern Australia, and is in greatest numbers in sheltered habitats. It is of mottled appearance, the upper body having rows of large spines surrounded by discs. While it can act as a scavenger, it is also an active predator of molluscs and can alter community structure by preventing establishment of beds of mussels and scallops. It has fissiparous reproduction, that is the animal divides in two to create new individuals. It often has up to eleven arms, which may be of different lengths due to regeneration and loss. Maximum diameter up to 500 mm. 

References: Graham J. Edgar. Australian Marine Life, 2nd Edition, 2008. Reed New Holland Publishers. pp. 401-2.

Neville Coleman, Sea Stars. Echinoderms of the Asia/Indo-Pacific. Neville Coleman’s Underwater Geographic Pty Ltd, 2007. p14.

Atlas of Living Australia website at https://bie.ala.org.au/search?q=coscinasterias+muricata. Accessed 10/10/2018.