Striped to match the arms of the feather star it lives in, and it changes with the host.
A squat lobster to about 2 cm with a long flattened rostrum, slender claws held forward, and a body striped lengthwise in a pattern that matches the arms of its host feather star — black and white on a black crinoid, red and cream on a red one, yellow on yellow. Individuals do not change colour; a given animal is found on a host it already matches, and a crinoid of an unusual colour will carry a squat lobster of that colour.
An obligate associate of crinoids, living deep between the arms near the central disc and moving out along an arm when the host is disturbed. One or two to a host is usual. The same feather star frequently carries a Laomenes shrimp and a small clingfish, so a crinoid worth searching is worth searching properly. Recorded from about 3 to 30 m. The animal retreats inward as a light approaches, so the working method is to light the crinoid from a distance, find the stripes, and close in on the line rather than sweeping the beam across the arms.
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.