Echinaster arcystatus

Pale mosaic seastar
Echinaster arcystatus
Echinaster arcystatus, Flinders Is, TAS, Photo: Andrew Green
Echinaster arcystatus
Echinaster arcystatus, Photo: Rick Stuart-Smith
Echinaster arcystatus
Echinaster arcystatus, Chain of Bays, SA, Photo: Andrew Green
Echinaster arcystatus
Echinaster arcystatus, Wilsons Promontory, Vic, Photo: Andrew Green
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Echinaster arcystatus
Echinaster arcystatus
Echinaster arcystatus
Echinaster arcystatus


Temperate Australasia


Resembles Plectaster decanus, but grows to a larger size and has a paler, less distinctive network of small spines over the upper body surface, and arms that are rounder in cross-section and flabby. It is an uncommon species that feeds mainly on encrusting sponges and other sessile animals.


Max Size: 36 cm

Sea Temperature Range: 12.4-22.2°C

Depth: 0-40m

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: Frequent (19.7% 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: Solitary (1 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