A small gasflame nudibranch Another small gasflame nudibranch Smal small gasflame nudibranch, slightly different view. Photos Johan Swanepoel A silvertip nudibranch. Photo Guido Zsilavecz The head of the second gasflame shown above. Note the "corrugated" section between the rhinophores, and how much lower it is than the one shown below. Photo Johan Swanepoel Detail of the head of the silvertip nudibranch shown above. Note that the "corrugated" section forms a tall crest. Photo Guido Zsilavecz	Gasflame nudibranch vs. silvertip nudibranch Gasflame nudibranchs (Janolus nakaza, previously Bonisa nakaza) are variable in colouration, and while a yellow/blue and yellow/white versions are most common, there are other variations, including white. Silvertips nudibranchs (Janolus capensis) are less variable, always having silver tips to their cerata. They are usually distinguishable in that with the silvertip red digestive tract extensions are usually visible within the cerata. The digestive tract of the gasflame nudibranch does not extend into the cerata, yet I've seen numerous individuals which are, to my mind, clearly gasflames, but have cerata with translucent bases and something extending into it. The question now is, is the identification correct? This is the question Johan Swanepoel is asking, as the one specimen he photographed shows these red extensions, yet all in all it has the "feel" of a gasflame. There is another identification characteristic one can use: between the rhinophores is a corrugated section, which in the silvertip forms a tall crest, while in the gasflame it is usually barely visible. If one now compares the details between the specimens shown, it seems clear to me that Johan's photos show a gasflame. What the red extension is, I do not know. For more details on this species, see "Nudibranchs of the Cape Peninsula and False Bay" available directly from SURG or better dive and book stores in Cape Town.
References: Nudibranchs of the Cape Peninsula and False Bay, G Zsilavecz, 2007 Nudibranchs of Southern Africa - a guide to the opisthobranch molluscs of southern Africa, T. Gosliner, 1987
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