Southern Australia from southern New South Wales, Victoria, Tasmania, South Australia.
UPPER: Bicheno, eastern Tasmania, May 1985, 18mm long.
LOWER LEFT: Bicheno, eastern Tasmania, May 1985, 21mm long.
LOWER RIGHT: Sisters Is., NW Tasmania, 15m, August 1985, 17mm long.
PHOTOS: Bill Rudman.
Tha mantle is a translucent white colour often tinged with pinkish purple, with a bright purple submarginal band. Inside the purple band are scattered bright orange patches of various shapes and sizes. The simple colourless gills usually have an orange axis and the translucent white rhinophore clubs have an orange line down the posterior midline. Closely packed mantle glands occur all around the mantle edge.
Similarly coloured species
Digidentis perplexa is very similar in colour to Chromodoris ambiguus especially in specimens of D. perplexa where the submarginal purple line is broken into a series of spots. However C. ambiguus is much more ovate with a prominent mantle overlap, whereas in D. perplexa the body is elongate, the mantle overlap along the sides relatively narrow. In C. ambiguus the gills are translucent with white speckling and the rhinophore clubs are a translucent straw colour with white edging to the lamellae while in D. perplexa both gills and rhinophores are white with bright orange markings. The two species can be clearly separated by the differences in their internal anatomy.
Another species, Chromodoris alternata, is also very similar in colour, the main difference being that it has a large orange-brown patch covering the central part of the mantle.
At present this species is known from Tasmania, South Australia and Victoria in south-eastern Australia, the same region in which the similarly coloured C. ambiguus and C. alternata occur.
• Rudman,W.B.,(1987). The Chromodorididae (Opisthobranchia : Mollusca) of the Indo-West Pacific: Chromodoris epicuria, C. aureopurpurea, C. annulata, C. coi and Risbecia tryoni colour groups. Zoological Journal of the Linnean Society 90: 305-407.
Rudman, W.B., 1999 (June 1) Digidentis perplexa (Burn, l957). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/digiperp