Re: Halgerda formosa & H. punctata

January 30, 2003
From: Terry Gosliner

Dear Bill,
Re your comments on Danny Van Belle's Halgerda from Thailand. I certainly agree with you that the specimens of Halgerda formosa that you illustrate from Mauritius are dead-ringers with Bergh's original description. I have some specimens from Madagascar that are somewhat intermediate in their abundance of spots. My intuition tells me that they all represent a single species. What we need to do to verify this is to examine the anatomy of one of the Mauritian specimens to see if it is consistent with the East African material. If the two prove to be different, then the East African animals need a new name, since Halgerda punctata is clearly a distinct species as evidenced by the photo on your site that is identical to Farran's drawing from Sri Lanka, with numerous elevated tubercles, rather than elevated linear ridges. Shireen and I would be happy to have a look at any Mauritian material of H. formosa if specimens are available.
All the best,
Terry

tgosline@calacademy.org

Thanks Terry,
I had forgotten Erwin Koehler's photo of Halgerda punctata. Danny Van Belle's photo and East African specimens, such as in Bernard Picton's photo, certainly match what I previously thought incorrectly (Rudman, 1978) was Farran's H. punctata. If it turns out on anatomical examination to be different from 'true' H. formosa, as typified by the Mauritian photos, it may be a third distinct species in the group. Another mystery is the one in Lindsay Warren's photo from Madagascar.
Best wishes,
Bill Rudman

Note added 31 January 2003: The reply I posted yesterday to Terry's message didn't make sense, because I had ignored Erwin Koehler's photo of H. punctata, so since its only been 24hrs I have replaced my reply. I don't usually change things on the Forum because it will destroy the Forum's archival nature, but in this case a correction would have been more confusing .... Bill

Rudman, W.B., 2003 (Jan 30). Comment on Re: Halgerda formosa & H. punctata by Terry Gosliner. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/9096

Factsheet

Halgerda formosa

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