Goniobranchus splendidus (Angas, 1864)

Distribution: 

Common throughout the Solitary Islands Marine Park. Endemic to New South Wales and southern Queensland.

Ecological Notes: 

Found on or near its food source on walls and reefs to depths of 25 m. Feeds on the pink encrusting sponges, Aplysilla rosea and Darwinella gardineri, members of the family Darwinellidae, as well as species of the Dictyodendrilla family.

Additional Notes: 

This chromodorid is extremely variable in shape and number of red spots, which may be almost absent. Specimens from northern New South Wales often have only the one large central red blotch, those from the southern part of its range have large spots scattered over the mantle. Rhinophores and edges of gills are bright red, the mantle with bright yellow/orange edge. The animal in the lower photograph is a rare form without a red spot. This colour form has been recorded as far north as Heron Island on the southern Great Barrier Reef. Grows to 60 mm.

References: 

Gary Cobb, David Mullins, Nudibranchs Encyclopedia, 2nd Edition, 2015. Publishers Thomas Slone, Masalai Press and Tim Hochgrebe, Underwater Australasia. p.132.

Undersea Jewels, A colour guide to nudibranchs, Gary Cobb and Richard C Willan. Australian Biological Resources Study, Canberra, 2006. p.132.