Re: Chromodoris multimaculosa from Bicheno, Tasmania

May 31, 2010
From: Capt John Silberberg

Concerning message #23688:

Hi Bill

They were still there on 28 May 2010.

There was a heavy surge and while I was watching, one was washed out. I caught it, photographed it and returned it to the reef.

Locality: The Rock, Waubs Bay, Bicheno, 12 metres, Tasmania, Australia, Tasman Sea, 28 May 2010, Rocky Reef. Length: 15 mm. Photographer: Capt John Silberberg.

Also, better pics attached, including what appears to be an egg mass.


Silberberg, Capt J.M., 2010 (May 31) Re: Chromodoris multimaculosa from Bicheno, Tasmania. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear John,

Thanks very much for these much clearer photos. As Greg Close says in his accompanying message [#23694] I was wrong in identifying your animal as C. multimaculosa, they are a spotted form of C. epicuria. In these photos the mantle is clearly translucent with white surface pigmentation.

The egg mass is interesting because the large eggs suggest the owner of them has direct development which means that the eggs hatch out as small crawling slugs rather then as small free-swimming veliger larvae. I can't find any record of its eggs so it would be interesting to know if anyoine else has found similar egg masses associated with C. epicuria.

The other interesting bit of information I can get from your photos is that they are clearly eating a large sponge colony and from the stringy network of fibres we can see it most probably a darwinellid sponge. Certainly the purplish outer layer of the colony is almost certainly Chelonaplysilla violacea but I am not sure whether the inner yellow region is a separate sponge or the inner pasrt of the Chelonaplysilla colony. Whatever it is, the nudibranchs have burrowed deeply into it. Large clusters of feeding animals like this support the idea that this is a direct developing species. For example, the southeastern Australian species, C. tasmaniensis, is a direct developer and is often found in groups like this on its favoured sponge Darwinella gardineri. I have reported C. epicuria feeding on D. gardineri, so your photos showing it in Chelonaplysilla violacea is a valuable addition to our knowledge.

Best wishes,
Bill Rudman

Rudman, W.B., 2010 (May 31). Comment on Re: Chromodoris multimaculosa from Bicheno, Tasmania by Capt John Silberberg. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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