Halgerda willeyi? mating with???

May 2, 2002
From: Erwin Koehler

Dear Bill,
At Coon's website is a photo of 2 mating Halgerdas. The right one is Halgerda wasinensis, but who is the other one???
. Bob Bolland wrote: "No idea at all about this... I've never seen a Halgerda this dark before."


Koehler,E., 2002 (May 2) Halgerda willeyi? mating with???. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5246

Dear Erwin,
Thanks for finding this photo. The owner of the website is Mr Naohisa Arai, who has given me permission to use his interesting photo.
Details are: Yaeyama Islands, Okinawa, Japan [Lat N 24 degrees Long E 124 degrees]. mid-May, 2001. Environment is a reef region at depth of 43ft.

I suspect this species is closer to H. willeyi then H. wasinensis. Typical H. wasinensis from East Africa has a black background and numerous thin ridges on the mantle. In H. willeyi there are a few ridges, and the background colour of the mantle is translucent white with black lines. In the animal on the right the black lines are a lot thicker than usual but if this is a melanistic variety that would be expected. In the animal on the left, which is mating with the other, the black lines are even broader, and the yellow lines along the ridges are absent.

Whether this is a form of H. willeyi or a separate species I wouldn't know, but there is again a clear lesson to be learned here - don't describe new species from a single specimen!
Best wishes,
Bill Rudman.

Rudman,W.B., 2002 (May 2). Comment on Halgerda willeyi? mating with??? by Erwin Koehler. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5246


Halgerda willeyi

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