A pale round urchin with short spines, often carrying pieces of rubble and weed on its upper surface.
To about 13 cm, one of the larger eastern Pacific urchins. Dense, very short spines over a dark test giving a felted look, and it often carries debris.
The green sea urchin is much smaller with visibly longer spines.
No depth range is given in the sources consulted. It is recorded at about fourteen per cent of surveyed tropical eastern Pacific sites, averaging three per transect, and runs from the Gulf of California to Panama plus the Galapagos.
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.