Coscinasterias muricata

Eleven-arm star
Coscinasterias muricata
Coscinasterias muricata, Hobart, TAS, Photo: Graham Edgar
Coscinasterias muricata
Coscinasterias muricata, Adelaide, SA, Photo: Ian Shaw
Coscinasterias muricata
Coscinasterias muricata, Bass Strait, TAS, Photo: Graham Edgar
Coscinasterias muricata
Coscinasterias muricata, Port Stephens, NSW, Photo: Andrew Green
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Coscinasterias muricata
Coscinasterias muricata
Coscinasterias muricata
Coscinasterias muricata


Temperate Australasia


Mottled appearance, with rows of large spines surrounded by discs along its upper surface. The number of arms is usually 11, but can vary from 7 to 14. While the species can also act as a scavenger, Coscinasterias muricata is such an active predator of molluscs in sheltered marine habitats that it is considered a keystone species; it can alter community structure by preventing the establishment of beds of mussels, scallops, etc. The species was called C. calamaria until recently. That name is now reserved for a close tropical relative, which has slightly differently shaped plates on the arms. If broken off, each arm can regenerate into a complete animal.


Max Size: 50 cm

Sea Temperature Range: 10.3-23.6°C

Depth: 0-150m

Habitat Generalization Index: N/A

Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.

Conservation and Rarity

IUCN Status: Not Evaluated

Occurrence: Common (21.2% of sites)

Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed

Abundance: Few (4 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.

Edit by: GJ Edgar. 2008. Australian Marine Life. New Holland, Sydney