A crab under a centimetre living among the arms of a feather star, striped to match them.
A small crab, the carapace rarely over twelve millimetres and in this genus longer than it is wide and drawn out at the front into a long narrow rostrum. The legs are slender with hooked tips for gripping the host, and the colour follows the feather star it lives on: striped lengthwise in black and white, red and cream, or yellow, with the stripes running in the same direction as the markings on the arms. Harrovia, on the same hosts, is broader and rounded with no long rostrum, and the two are often photographed as one animal.
It is an obligate associate of crinoids, sitting deep among the arms and cirri near the central disc, and it feeds on material the host has already trapped. One or two to a host is usual. Of the animals that live on a feather star it is the one most often missed, because the shrimp and the squat lobster both come out along an arm when the host is disturbed and the crab works inward instead.
The search is the same as for the rest of the crinoid fauna, a light held to one side and a look for stripes running at the wrong angle to the arms, with the difference that this animal is found at the base of the arms rather than partway out. Species are separated on the carapace and the rostrum under magnification and several of those photographed in the region are not matched to a described species, so records stay at the genus. Recorded from about 5 to 30 m, on hosts on rubble and along current edges.
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.
