A short-spined southern urchin, purple, green or brown, wedged into rock crevices and often holding a piece of weed over itself.
Test to about 9 cm. Very variable in colour — white, purple, green and red in combination — with short, stout, blunt spines. Western Australian animals have the shortest and most compact spines.
The long-spined urchin of the same coast has long thin sharp black spines, which is the whole separation.
Surface to thirty-five metres on temperate reef, and it is the most abundant urchin over much of southern Australia, recorded at about two-thirds of surveyed sites at an average of thirty-seven per transect. It forms barrens.
The spines are blunt and there is no sting.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.