It was thought to be endemic to southern Australia and New Zealand but has since been documented as occurring in the Cape Peninsula as well.
This starfish has rows of pincer-like pedicellariae on both its upper and lower surface which gives it a prickly appearance.
[2] Coscinasterias calamaria mostly feeds on the blue mussel (Mytilus edulis) and other benthic invertebrates.
It seems that the abalone has some behavioural responses to attack that make it more likely to escape, one of which seems to be the production of a chemical deterrent by the mollusc.
It is difficult to establish the relative importance of the two forms of reproduction in this starfish but it has been shown that individuals in close proximity to one another have little genetic diversity while starfish collected at separations of as little as 50 metres (160 ft) have widely different genetic composition, particularly so in the case of subtidal populations.