About Goniobranchus setoensis (Baba, 1938)
This species is a chromodorid nudibranch. Its body is translucent white, marked with opaque white lines, purple spots, and a subsurface orange-red margin. A white line typically outlines the center of its back, and another line runs from between its rhinophores to the middle of the back, where it splits to form a loop around the gills. Outside the outermost white line, there is a single or double row of purple spots, which never have a white halo around them. Small white spots run along the mantle edge. The tips of the rhinophores and the outer parts of the gills are white. Goniobranchus setoensis was first described from Japan. It has often been confused with Goniobranchus decorus, and many existing records of Goniobranchus decorus are actually misidentifications of this species. It lives in the central Indo-Pacific, ranging from Japan to Sri Lanka, and east as far as the Marshall Islands and Kiribati. Goniobranchus setoensis and Goniobranchus decorus live in the same geographic range in the Marshall Islands. Goniobranchus setoensis feeds on sponges that belong to the family Aplysillidae.
