Carlson & Hoff, 1993
Known previously only from Guam. See Scott Johnson's record below from Marshall Ids.
UPPER: 64mm, Guam, Annae Is., 8m, 27 April 1969. LOWER: 49mm, Guam, Bile Bay, 14m, 24 April 1991. PHOTOS: Clay Carlson.
One of a group of white species of Halgerda with orange markings. This species is characterised by the orange-tipped tubercles, a sparse network of orange lines on the dorsum between the tubercles, and thin submarginal orange lines around the mantle edge. Known only from Guam.
There are three species of Halgerda with a network of orange lines. In H. malesso the network of lines sometimes fuse to form orange patches in the depressions, there are multiple fine orange lines around the mantle edge, and the fairly high tubercles are capped with orange. In Halgerda batangas, which also has a network of orange lines, the ridges and tubercles are low and rounded. The tubercles are capped with orange-red with a basal ring of white. The edge of the mantle is white with orange-red tubercles. The foot is edged with orange. The third species with an orange network is Halgerda terramtuentis. It has golden orange lines and the tubercles are capped with white.
• Bertsch, H. & Johnson, S. (1982) Three new species of dorid nudibranchs (Gastropoda: Opisthobranchia) from the Hawaiian Islands. The Veliger, 24(3): 208-218.
• Carlson, C.H. & Hoff, P.J. (1993) Three new Halgerda species (Doridoidea: Nudibranchia: Opisthobranchia) from Guam. The Veliger, 36(1): 16-26.
• Carlson, C.H. & Hoff, P.J. (2000) Three new Pacific species of Halgerda (Opisthobranchia: : Nudibranchia: Doridoidea). The Veliger, 43(2): 154-163.
Rudman, W.B., 2000 (June 26) Halgerda malesso Carlson & Hoff, 1993. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/halgmale
May 23, 2007
From: Harry Blalock
As well as Halgerda guahan [message #19937] I have also found Halgerda malesso recently on the island of Saipan. They seem to like the Grotto, as I have seen quite a few of them there now. Here are a few of my pictures.
Locality: Grotto, 50', Saipan, Northern Mariana Islands, Pacific, 18 February 2007, cave with lots of big rocks that fell in from the ceiling years ago. Length: approximately 4". Photographer: Harry Blalock.
firstname.lastname@example.orgBlalock, H., 2007 (May 23) Halgerda malesso from Nthn Marianas Ids. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19939
January 19, 2007
From: Yuji Fujie
Here we have two pictures from mating Halgerda malesso in Saipan.
Locality: LauLau Beach, 15m, Saipan, Northern Mariana Islands, Pacific Ocean, 21 May 2006, on the dead coral, near anemone fish. Length: 30 mm. Photographer: Yuji Fujie.
email@example.comYuji Fujie, 2007 (Jan 19) Mating Halgerda malesso from nthn Mariana Islands. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19190
June 27, 2000
From: Scott Johnson
Just before leaving Enewetak Atoll in late 1983, I ran across this pair of what is apparently Halgerda malesso underneath a chunk of dead coral rock at 30 meters on the western seaward slope of the atoll. The animals measured 24mm in length and are still the only two specimens of this species I've seen in the Marshalls.
Externally, the only difference in coloration I can see from Clay and Patty Jo's H. malesso from Guam is the more dense network of orange lines between the tubercles. The Enewetak specimens were considerably smaller, which may have been responsible for this difference in coloration. Although smaller, they showed they were mature by laying down an egg mass in captivity.
firstname.lastname@example.orgJohnson, S., 2000 (Jun 27) Halgerda malesso from Marshall Ids. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2623
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.
email@example.comCarlson, C. & Hoff, P.J., 1999 (Feb 4) Re: Halgerda malesso. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/539
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.