Plants living corallimorphs over its whole shell until the crab is invisible under them.
A spider crab with a carapace to about 5 cm, in itself a nondescript knobbly brown animal, which is almost never what a diver sees. It attaches living corallimorphs — disc anemones — to tubercles over the carapace and legs, and they grow there and multiply until the crab is completely covered by a cluster of fleshy discs. What moves across the sand is a bouquet with legs.
The corallimorphs sting and are unpalatable, and they continue to feed while being carried. As the crab grows it transfers them to the new shell after each moult, in the same way that the anemone hermit crab moves its Calliactis. On a silty slope the usual first sight is a clump of disc anemones apparently growing on open sand, which is not something disc anemones do — that is the identification. Nocturnal and slow. Recorded from about 3 to 30 m.
Older references list it as Cyclocoeloma tuberculata.
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.
