Re: Halgerda malesso

February 4, 1999
From: Clay Carlson


As far as we know, Halgerda malesso has not appeared in print since it's description in 1993. We have not found it outside of the Mariana Islands though have seen a slide of what appears to be H. malesso from the Marshall Islands. It is relatively easy to identify because of the fine submarginal orange/gold lines as well as the anastomosing (sp?) lines of the same color in the depressions. I've enclosed two scans -- neither of great quality.

UPPER: H. malesso 64mm, Guam, Annae Is., 8m, 27 April 1969
LOWER: H. malesso 49mm, Guam, Bile Bay, 14m, 24 April 1991

The animal that appears in Debelius as H. malesso and elsewhere quite often as H. carlsoni is an unnamed species. We have described this in a paper that should be out this year. I have enclosed a scan that shows the reticulate pattern of lines that occurs on the dorsum. Internally it differs from both H. malesso and H. carlsoni.


Merizo, Guam

Carlson, C. & Hoff, P.J., 1999 (Feb 4) Re: Halgerda malesso. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Clay,
I have put your scan of the new species with Erwin's photo on a separate page. I wondered whether the difference in reticulate pattern was a bit much for intraspecific variation.
Best wishes,
Bill Rudman.

Rudman, W.B., 1999 (Feb 4). Comment on Re: Halgerda malesso by Clay Carlson. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Halgerda malesso

Related messages

  1. Halgerda malesso from Nthn Marianas Ids
    From: Harry Blalock, May 23, 2007
  2. Mating Halgerda malesso from nthn Mariana Islands
    From: Yuji Fujie, January 19, 2007
  3. Halgerda malesso from Marshall Ids
    From: Scott Johnson, June 27, 2000

Show factsheet and all related messages