"A member of the family Discodorididae that mimics Phyllidiella pustulosa (Phyllidiidae). This is a good photo to portray and ‘expose’ this species because the gills are clearly visible, but when they are retracted the resemblance is perfect. In contrast, Aldisa williamsi (family Dorididae), which is probably also part of this mimicry complex, has a greenish background with large black areas, its rhinophores are pale yellow, and its gills are black."