Aldisa sp. 4

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Dorididae

PHOTO

Upper: Park Rynie, south coast KwaZulu-Natal, South Africa, 32 m, December 2001. Length: 18 mm. Photo: Valda Fraser.
Lower: Sodwana, South Africa, 15m. January 2002. Size: 12mm. Photo: Valda Fraser

This species appears to range from animals with a reticulate pattern of ridges all over the mantle to animals in which the network is more obscure, and riounded tubercles predominate. The tubercles appear to represent the junctions of the ridges. There are two or three crater like pits down the dorsal midline, the bottom of the pits having a number of dark brown oval spots. 

The only species I know of with a network of ridges over the mantle, as in this species, is Aldisa pikokai which is known at present only from Hawaii and the Marshall Ids in the central Pacific. That species also has two or three large sunken pits in the dorsal midline and sometimes these have dark spots. It is possible that this Sth African animal is Aldisa pikokai but we would need to check its anatomy and hopefully find some records in other parts of the Indo-West Pacific.

Authorship details
Rudman, W.B., 2005 (May 17) Aldisa sp. 4 [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/aldisp4

Related messages


Re: Aldisa sp. 4 from Madagascar

November 27, 2009
From: Les Clear

Concerning message #22881:

Hi Bill,

No the lovely blue colour was the pigment, which is how my wife spotted it in the first place. I was just using a very simple reef master camera.
Regards
Les

ann.clear@btinternet.com

Clear, L, 2009 (Nov 27) Re: Aldisa sp. 4 from Madagascar. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22895

Thanks Les,

It's certainly a spectacular colour. Looking more closely at Valda Fraser's upper photo on the Fact Sheet I can see a few of whitish blue spots on that animal as well. Perhaps this species exudes bluish-white secretions from small glands in the skin. If so the blue patches could well be such secretions - but that's just a guess - but it would explain why some animals don't show blue 'spots' and others don't.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Nov 27). Comment on Re: Aldisa sp. 4 from Madagascar by Les Clear. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22895

Aldisa sp. 4 from Madagascar

November 27, 2009
From: Les Clear


Hi Bill,

This colourful little fellow was photographed on a dive site called Vatosoa, Madagascar, we believe it is an Aldisa?

Locality: Mangilly, 8 meters, Madagascar, Mozambique, 17th sept 2009, shallow reef. Length: 2-3 cms. Photographer: Les Clear.

Les Clear

ann.clear@btinternet.com

Clear,L, 2009 (Nov 27) Aldisa sp. 4 from Madagascar. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22881

Dear Les,

I am pretty sure this is the animal I have been calling Aldisa sp. 4. All the records of it are from the western Indian Ocean. First one I've seen with such spectacular blue. Is the blue speckling a pigment or is it a flourescence effect from the lighting you were using?

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Nov 27). Comment on Aldisa sp. 4 from Madagascar by Les Clear. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22881

Aldisa sp from Reunion island

April 12, 2006
From: Philibert Bidgrain

Dear Bill,
Reunion Island sea slugs.

David Caron found this specimen. It look likes Aldisa sp 1 and Aldisa sp 2  with the presence of two large crater-like depressions and small pustules on the mantle. We can also observe a yellow margin on the foot ( posterior end)

Locality: Cap la Houssaye, Reunion Island, 3 m, indian ocean. Length: 20 mm. Photographer: David Caron

What's your opinion about this Aldisa?

Best Regards
Philibert Bidgrain
http://vieoceane.free.fr/runseaslug/indexslug.htm

pbidgrain@yahoo.fr

Bidgrain, P., 2006 (Apr 12) Aldisa sp from Reunion island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16280

Dear Philibert,
I am pretty sure your animal is the same as the one in message #5887 from Sth Africa, which I am calling Aldisa sp 4. The size of the 'craters' is quite remarkable making the animal very sponge-like.
Best wishes,
Bill Rudman

Rudman, W.B., 2006 (Apr 12). Comment on Aldisa sp from Reunion island by Philibert Bidgrain. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16280

Aldisa from Sth Africa

May 18, 2005
From: Colin Ogden

Hi,
I can't identify this nudi. Please can someone help.

Locality: Sodwana Bay, South Africa, Indian Ocean. Depth: 18 metres. Length: 3 cms. April 2005. Coral reef. Photographer: Colin Ogden

Regards
Colin Ogden

 

scubaco@iafrica.com

Ogden, C., 2005 (May 18) Aldisa from Sth Africa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13787

Dear Colin,
This is a species of Aldisa. Quite a number of species have a pair of crater like depressions on their back, like in your animal, which presumably are mean't to mimic the oscules or exhalent siphons in the sponges they feed on. We already have a couple of examples of this species from South Africa on the Forum, which I am calling Aldisa sp. 4. The only species I know of with a network of ridges over the mantle, as in your animal, is Aldisa pikokai which is known at present only from Hawaii and the Marshall Ids in the central Pacific. It is possible the Sth African animal is that species but we would need to check its anatomy and hopefully find some records in other parts of the Indo-West Pacific.
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (May 18). Comment on Aldisa from Sth Africa by Colin Ogden. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13787

Aldisa? from South Africa

March 26, 2002
From: Valda Fraser

Dear Bill
Please can you tell me what kind of Aldisa this is. I'm not sure if it is a variation of Aldisa sp. 4, or a separate species.

Location: Sodwana, South Africa, 15m
Date: January 2002
Size: 12mm
Thanks
Valda Fraser

valdafraser@mweb.co.za

Fraser, V., 2002 (Mar 26) Aldisa? from South Africa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6124

Dear Valda,
Just looking at the photos I would say this animal is probably a colour variant of Aldisa sp. 4, but we could only be sure when their anatomy is looked at and more specimens - and possibly an intermediate - are found.
Cheers,
Bill Rudman

Aldisa from South Africa

January 5, 2002
From: Valda Fraser


Dear Bill
A friend found this amazing animal. Your input will be appreciated because I'm 100% clueless! Thanks.

Locality: Park Rynie, south coast KwaZulu-Natal, South Africa, 32 m
Date: December 2001
Size: 18 mm

Regards
Valda Fraser

valdafraser@mweb.co.za

Fraser, V., 2002 (Jan 5) Aldisa from South Africa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5887

Dear Valda,
This is indeed an amazing animal. I am pretty sure it is a species of the genus Aldisa. Species of Aldisa tend to be very good at camouflaging themselves to look like sponges. As in your animal they often have two or three marks or actual pits in the midline to mimic the exhalant pores [oscules] of the sponge colonies. Your animal has certainly developed the imitation pores to a greater degree than I can recall in any other species.

I think it is an unnamed species but Sandra Millen or Terry Gosliner may recognise it.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Jan 5). Comment on Aldisa from South Africa by Valda Fraser. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5887