Found in pairs, one animal following the other with its rhinophores on its tail.
A large dorid to about 8 cm, pale grey to fawn scattered with dark purple-brown spots each ringed in a paler halo, with an orange-yellow mantle margin and orange rhinophores and gill. The mantle skirt is wide and lifts and flaps as the animal moves, and it moves faster than most dorids. The genus Risbecia, under which it was long listed, has been subsumed into Hypselodoris.
The behaviour is what sets it apart. Animals are very often found in pairs, one directly behind the other with its rhinophores touching the leader’s tail, and a following pair will travel like that for long distances. The function is not settled — mate guarding and trail-following have both been proposed — but the pairing is consistent and is the quickest field mark for the species. Feeds on sponges. Recorded from about 3 to 30 m, and one of the larger and more conspicuous slugs on a muck 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.
