Two long horns on the snout, on a small decorated spider crab that emerges after dark.
A spider crab whose carapace reaches about 5 cm, pear-shaped and narrowing to two slender horns that project forward and slightly apart, together about a third of the body length again. The legs are long and thin. The shell and legs carry tubercles and hooked bristles that hold whatever the crab attaches to itself — sponge, hydroid, algae, bits of debris — so colour is not usable and the horns are. The other decorated crabs on the same ground separate cleanly: the decorator crab Camposcia retusa has a short blunt snout and is buried entirely under its covering, the red spider crab has a short forked rostrum and a broad heavily spined shell, and the corallimorph decorator crab is round and carries live corallimorphs.
It is found on rubble and reef slope, often among hydroids, gorgonians and black coral, from about 5 to 35 m, and it is nocturnal — by day it sits still and covered, which in practice means it is not seen at all. It feeds on algae, detritus and small sessile animals. The decoration is placed deliberately, piece by piece, and held by the hooked bristles rather than glued, so a crab moved to a different background will re-cover itself over the following days.
The regional record for this species is thin and scattered, in part because a crab covered in hydroids at night is easily passed and easily recorded as something else.
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.
