A dark sacoglossan speckled in pale blue, with orange and blue bands along the parapodia.
A sacoglossan to about 4 cm, the body dark grey to near black and densely speckled with small pale blue to white spots, with a pair of parapodia held up along the back like folded wings and edged in bands of orange, blue and white. The rhinophores are rolled tubes rather than the lamellate clubs of a dorid, which is the quick way to place a slug of this shape with the sacoglossans rather than the nudibranchs.
Thuridilla gracilis shares the ground and the shape and is also dark with small pale spots; the separation is in the parapodial margin, which in that species carries a band of orange with a paler line inside it rather than the orange, blue and white banding here. Thuridilla lineolata, again on the same ground, is lined rather than spotted. Both are found on algal turf and rubble in shallow water and both move steadily rather than sitting still, which makes them harder to photograph than their size suggests.
Sacoglossans feed by piercing individual algal cells with a single-toothed radula and sucking out the contents. Several members of the group retain the chloroplasts from that meal in the tissues of the digestive gland and keep them working for a period, and the extent to which any given species does this varies. Recorded from about 2 to 25 m.
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.
