RE: Juvenile Halgerda sp. from Taiwan

July 18, 2002
From: Nishina Masayoshi

Dear Bill,
Todd Garthwaite's Juvenile Halgerda sp. from Taiwan recalls to me another my puzzle. I sometimes find Halgerda which are difficult to identify like in the upper photo. I've been wondering whether it's H.willeyi or H.wasinensis?
I feel my animal and Todd's animal looks the same. Both have the conspicuous prominent bright yellow ridges which don't look like those of H. elegans to me. It is difficult say something without seeing the rhinophores and the gill but I feel that
Todd's animal is more similar to H.willeyi or H.wasinensis then H. elegans. I have attached two more photos [lower] which I am also not sure of. I feel those are rather say similar to darker color form of H.willeyi.

Data: Hachijo Island Japan
Upper Right:30 June, 2001., Depth: 8m, Length:40mm
Lower Left: 02 Dec, 2001., Depth: 8m, Length:40mm
Loweer Right: 18 Dec, 2001., Depth: 8m, Length:50mm

Best Regards,
Nishina Masayoshi

Masayoshi, N., 2002 (Jul 18) RE: Juvenile Halgerda sp. from Taiwan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Nishina,
It is almost impossible to identify little juveniles like this. You could be right in thinking Todd's animal is H. willeyi. Concerning your animals, have a look at the message showing a very dark animal and a much lighter one mating. I suspect all of the photos you have sent here are the same species. It is probably a form of Halgerda willeyi but I suspect this colour grouop needs further study. For example in your lower right photo the rhinophore stalks are black with a white line where normally you would expect a white stalk with a black line
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Jul 18). Comment on RE: Juvenile Halgerda sp. from Taiwan by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Halgerda willeyi

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