Chromodoris cf. tasmaniensis
Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae
PHOTO
Rapid Bay Jetty, South Australia.
Upper Photo: Depth 9.5m, 4cm in length. 18 February, 2001. Lower Photo: Animal feeding on a red aplysillid sponge on a jetty pylon at a depth of 5m, 3.5cm in length. 26 March 1998. PHOTOS: John Chuk.
This species has similarities in colour to Chromodoris tasmaniensis but I very much doubt if they are closely related. As I discuss on the C. tasmaniensis Page, and elsewhere, there are many species of chromodorid in south-eastern Australia with a colour pattern consisting primarily of a white background and red spots. I have suggested that this concentration of similarly coloured, but unrelated species, is an example of mimicry. Of particular interest is the way that species with a wide geographical distribution in southeastern Australia change details of their colour pattern to match the slightly different patterns in subregions of southeastern Australia. For example C. tasmaniensis in New South Wales has large, similar sized red or orange spots scattered over its mantle to match the common colour pattern in this area. In the Bass Strait region further south, the common colour pattern differs in having a submarginal band of smaller spots around the mantle edge. C. tasmaniensis in Bass Strait differs from New South Wales animals in having small spots around the margin as well.
This animal fits the prevailing colour pattern in southern waters very well. It also feeds on one of the pink species of Darwinella which so many of these red-spotted species eat.
References:
•Rudman, W.B. (1983 ) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris splendida, C. aspersa and Hypselodoris placida colour groups. Zoological Journal of the Linnean Society, 78: 105-173.
•Rudman, W.B. (1987a) 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. (1991) Purpose in Pattern: the evolution of colour in chromodorid nudibranchs. Journal of Molluscan Studies, 57, (T.E. Thompson Memorial Issue): 5-21.
See John Chuk's message.
Authorship detailsRudman, W.B., 2001 (May 21) Chromodoris cf. tasmaniensis [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/chrocftasm
