Halgerda tessellata
(Bergh, 1880)
Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Dorididae
DISTRIBUTION
Originally described from Palau, it has a wide Indo-West Pacific distribution from the western Indian Ocean to eastern Australia.
PHOTO
Dar es Salaam, Tanzania, July 1977. PHOTO: Bill Rudman.
Grows to about 45mm long.
Reference:
• Bergh, L.S.R. (1880). Malacologische Untersuchungen. In: C.G. Semper, Reisen im Archipel der Philippinen, Wissenschaftliche Resultate. Band 2, Suppl. 1: 1-78, Pls. A-F.
Rudman, W.B., 1999 (November 16) Halgerda tessellata (Bergh, 1880). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/halgtess
Related messages
Halgerda tessellata from Indian Ocean
March 16, 2009
From: Sandrine Flodrops
Concerning message #2950:
Dear Bill and Valda,
here are some pictures of Halgerda tessellata with the same pattern as in Valda Fraser's message. South Africa, Mayotte and Reunion have a lot of similarities in their sea slug fauna.
Locality: Balcon sur le bleu "Passe en S", 12 metres, Mayotte, Indian Ocean, 4 march 2009. Length: 25 mm . Photographer: Sandrine Flodrops.
I thinks it's interesting for the forum.
Best regards.
Sandrine.
hugues.flodrops@wanadoo.fr
Flodrops, S.H., 2009 (Mar 16) Halgerda tessellata from Indian Ocean. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22320
Dear Sandrine,
It is indeed interesting for the Forum. My first experience with this species was when I found a specimen in Tanzania [see Fact Sheet photo], so I was quite puzzled when I first saw western Pacific animals with a concentration of white near the mantle edge [see message #22035]. Whether we should consider these geographic differences to be 'just variations' or 'subspecies' or 'geographic species pairs', is really a semantic argument. What the differences indicate is that the Indian Ocean and Western Pacific populations have been isolated from each other for a long time. One valuable consequence of the Forum is the growing evidence we are getting of how the western Indian Ocean fauna stretches right across to Thailand, with Indian Ocean 'forms' rather than western Pacific 'forms' occurring their. For example, Erwin Koehler's animal from Thailand [message #3607] looks like the one from East Africa.
Best wishes,
Bill Rudman
Re: Halgerda tessellata from sthn Queensland
November 12, 2008
From: Gary Cobb
Concerning message #20509:
Hi Bill and everyone!
While we're on the subject of Halgerda... here are some photos another equally beautiful and medium sized nudibranch to add to the Forum's collection. Halgerda tessellata. I have included a really nice ventral view where you can see all the features!
Locality: Mooloolaba, Sunshine Coast, 15 m, Queensland, Australia, Pacific Ocean, 11 November 2008, Subtidal. Length: 18-27 mm. Photographer: Gary Cobb.
Cheers
Gary
gary@nudibranch.com.au
Cobb, G.C., 2008 (Nov 12) Re: Halgerda tessellata from sthn Queensland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22035
Thanks Gary,
These photos show what I consider to be the Western Pacific colour form of the species. You will note the white specks and spots are realtively small except in a wide band around the mantle edge. In the Indian Ocean form the white spots are evenly spread over the brown parts of the mantle with no marginal concentration.
Best wishes,
Bill Rudman
Halgerda tesselata from Tofo, Mozambique
August 24, 2007
From: Natasja Vandeperre
Hello Bill,
This is a picture of Halgerda tessellata.
Locality: Tofo, Mozambique, Indian Ocean, 20 July 2007. Photographer: Natasja Vandeperre.
Greetings,
Natasja
postmaster@naaktslakken.be
Vandeperre, N., 2007 (Aug 24) Halgerda tesselata from Tofo, Mozambique. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20509Thanks Natasja,
Bill Rudman
Halgerda tesselata from the Marianas Ids
November 11, 2005
From: Takao Urasawa
Dear Dr Rudman
I found this Halgerda tesselata in March this year.
Locality: Lau Lau beach, Saipan, Northern Mariana Islands. Pacific Ocean. Depth: 10 m. Length: 20 mm. March 2005. Photographer: Takao Urasawa
Takao Urasawa
dswith@isletwind.com
Dear Takao,
Thanks for this photo which shows the Pacific colour form of this species very well
Best wishes,
Bill Rudman
Halgerda tessellata from Mayotte
December 9, 2003
From: Marina Poddubetskaia
Dear Bill,
In Mayotte I've found several Halgerda species, including this Halgerda tessellata.
Date: November 04, 2003
Location: Mayotte Island, France, Indian Ocean
Site : Passe en S, buoy n° 8bis
Depth: 17m
Length: 16-18mm
Cordially,
Marina.
nembro@nembro.info
Poddubetskaia, M., 2003 (Dec 9) Halgerda tessellata from Mayotte. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/11629Thanks Marina,
Bill Rudman
Halgerda tessellata from Malaysia
April 23, 2002
From: Kheong Sann Chan
Hi Dr. Rudman,
Hers is another nudibranch from Pulau Dayang off the East Coast of Malaysia, 14 April, 2002. Depth varied approximately 15-23m deep.
Thanks,
Kheong.
kschan@mail.dsi.nus.edu.sg
Sann Chan, K., 2002 (Apr 23) Halgerda tessellata from Malaysia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6773Dear Kheong,
This is Halgerda tessellata. All species of Halgerda are characterised by the pattern of ridges over the mantle, usually sharp but in the case of this species, more flattened. In this species the ridges are a yellow-brown and the spaces in between are dark brown with bright white spots.
Best wishes,
Billl Rudman
Halgerda tessellata from Exmouth, W.A.
April 9, 2001
From: Kirk Gibson
Dear Bill,
Here is another nudibranch from Exmouth, northern Western Australia
Kirk Gibson
captainkirk@wn.com.au
Gibson, K., 2001 (Apr 9) Halgerda tessellata from Exmouth, W.A.. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4109Thanks Kirk,
This is Halgerda tessellata
Best wishes,
Bill Rudman
Halgerda tessellata from Thailand
January 23, 2001
From: Erwin Koehler
Dear Bill,
Here is a Halgerda tessellata from Thailand,
Similan Island #9, divesite "Snapper Alley", depth 12m, size 31mm, Dec. 22, 2000
Erwin
Medslugs.Koehler@t-online.de
Koehler, E, 2001 (Jan 23) Halgerda tessellata from Thailand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3607Thanks Erwin,
Your photos remind that I peomised to look out some New Caledonian photos of this species,
Best wishes,
Bill Rudman
Halgerda tessellata variations
January 4, 2001
From: Scott Johnson
Hi Bill,
Attached are three apparently geographic variations of Halgerda tessellata. E026-1 is from the Marshall Islands, where the two dozen or so specimens observed were colored approximately the same. P026-1 is from Pohnpei in the eastern Carolines, and it was similar in color to one other specimen observed there. S087-2 is from the Solomon Islands, and I saw at least two others there with the same color form. All measured within the 15 to 25mm range.
Scott
johnson@kmr.ll.mit.edu
Dear Scott,
Thanks for the photos. I also feel that these are colour variations of one species. When I catch up with the backlog of messages I'll have a look for a few more colour forms. The Solomon Ids form seems to be the most common one in the South Pacific. I have just seen it again in Lifou and it s not uncommon on the Great Barrier Reef.
Best wishes,
Bill Rudman
Halgerda tessellata in southern Africa
September 3, 2000
From: Valda Fraser
Dear Bill]
Just in case someone is interested in distribution patterns. Halgerda tesselata occurs along the southern coast of Africa as well.
Locality: Sodwana, northern KwaZulu-Natal SOUTH AFRICA - 28m
Date: August 2000
Size: 25mm
Regards
Valda Fraser
valdafraser@mweb.co.za
Fraser, V., 2000 (Sep 3) Halgerda tessellata in southern Africa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2950Thanks Valda,
I guess western Indian Ocean is more accurate than east Africa. I've changed the sentence.
Bill Rudman.
Halgerda tessellata from the Maldives
November 17, 1999
From: Erwin Koehler
Dear Bill,
Is this Halgerda tesselata?. I photographed it at the Maldives, Olhahali Is., divesite
"Olhahali Caves", date Nov. 01, 1999, depth 26m, size 24mm
Best wishes,
Medslugs.Koehler@t-online.de
Koehler, E., 1999 (Nov 17) Halgerda tessellata from the Maldives. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1535Dear Erwin,
I guess this is H. tessellata, though the brownish orange ridges seem proportionally large.
Bill Rudman.
Rudman, W.B., 1999 (Nov 17). Comment on Halgerda tessellata from the Maldives by Erwin Koehler. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1535