Colour forms of Halgerda dichromis mating

Dear Valda,

I am so glad your were decided to brave the 'current from hell'.  Halgerda dichromis was based on a single species similar in colour to the Fact Sheet photo [message #1541] so I found it quite difficult to identify other coloured animals with this species - and felt quite brave in suggesting your brownish specimen [message #2053] could be the same species. Fortunately Fahey & Gosliner (2003) later studied the anatomy of it and the animal in your message #2679 and could find no anatomical differences. Your find of these two animals mating is an excellent confirmation of the colour variability to be found in this species.

It does of course raise the question of whether Halgerda theobroma from western Australian coast of the Indian Ocean is the same species?

• Fahey, S. J. & Gosliner, T. M. (2003) Redescription of Halgerda graphica Basedow and Hedley,1905, with observations on external morpohological variation within selected species of Halgerda (Mollusca: Nudibranchia). Proceedings of the California Academy of Sciences, 54, 393-406.

Best wishes,
Bill Rudman