Colour variations of Halgerda willeyi

September 8, 2007
From: Gary Cobb

Hi Bill and everyone!
I want to present to you a composite shot I put together with two entirely different Halgerda willeyi specimens. Here on the Sunshine Coast this species his very variable.

Locality: Sunshine Coast near Mooloolaba, 10-20 m, Queensland, Australia, Pacific Ocean, 10 June 2007, Subtidal. Length: 16-60 mm. Photographer: Gary Cobb.

Gary Cobb

Cobb, G.C., 2007 (Sep 8) Colour variations of Halgerda willeyi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Gary,

These pair certainly have the black band around the middle of the rhinophore club which I have said before seems to separate H. willeyi from H. elegans but on looking through many photos I can't say I am 100% sure that this is not a variable character. The general colour pattern of the lower animal in your composite photo is identical to that of H. elegans, which would seem to sugest that H. elegans is just a colour form of H. willeyi.

If this species is quite common on the Sunshine Coast it would be interesting to get a range of photos showing variability in overall mantle colour pattern and also rhinophore colour pattern.

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Sep 8). Comment on Colour variations of Halgerda willeyi by Gary Cobb. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Halgerda willeyi

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