Deep magenta with a white margin that dissolves into speckles rather than ending cleanly.
A dorid to about 7 cm, the mantle a saturated magenta to violet with a broad white border whose inner edge is not a line but a scatter of white flecks fading into the purple. The rhinophores and gill plume are orange-yellow. The near-identical Hypselodoris bullockii has a white margin with a clean inner edge and is generally paler; the two were treated as one species for years, and the speckled transition is the mark that separates them.
Feeds on sponges of the family Thorectidae and stores the sponge’s compounds in mantle glands concentrated around the rim. Frequently found in pairs on the food sponge, with a white spiral egg ribbon beside them. Recorded from about 5 to 30 m on rubble and rock. Large, slow and strongly coloured, and one of the easier nudibranchs to get a clean frame of — the difficulty is that magenta clips readily under a strobe, and the flecked border is the first thing lost when it does.
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.
