A thick pale sea star with five short blunt arms and a swollen, smooth-granular body.
A heavy sea star to about 25 cm across, with a swollen central disc and five short, thick, blunt-ended arms, so that the whole animal looks inflated rather than radiating. The upper surface is smooth to finely granular with no spines and no knobs, pale cream to pink, and usually flecked or blotched with brown, with the darker granulation concentrated toward the centre. The underside is paler, with broad grooves of tube feet running the length of each arm.
It feeds in the way of the family, by everting the stomach onto the surface it is sitting on and digesting the algal film, encrusting growth and detritus in place, and it moves slowly enough that a feeding animal can be watched for the whole of a dive without moving far.
The two animals it is taken for are both on the same ground. A cushion star is a pentagonal cushion with no arms to speak of, and the horned sea star carries hard dark cones on the disc and arms. Neither has this one’s proportions, a fat disc with five short soft-looking arms and no ornament at all. Recorded from about 3 to 30 m on rubble, dead coral and slope.
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.