Flabellina riwo
Gosliner & Willan, 1991

Order: NUDIBRANCHIA
Suborder: AEOLIDINA
Family: Flabellinidae

DISTRIBUTION

Indo-West Pacific.

PHOTO

Wakatobi, Sulawesi, Indonesia, Banda Sea. Depth: 10 metres. Length: 1 inch. 5th September 2005. sandy rubble bay area. Photographer: Candy Armstrong

This species is very similar in shape to Flabellina bicolor, including having long oral tentcles with flattened, paddle-shaped tips. It differs in having a reticulate white pattern on the body, rather than a uniform dusting of white, and a purple band and a yellow band on each ceras, rather than just the yellow or gold band found in Flabellina bicolor.

  • Gosliner, T. M. & Willan, R. C. (1991) Review of the Flabellinidae (Nudibranchia: Aeolidacea) from the tropical Indo-Pacific, with the descriptions of five new species. The Veliger, 34(2): 97-133.
Authorship details
Rudman, W.B., 1999 (July 1) Flabellina riwo Gosliner & Willan, 1991. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/flabriwo

Related messages


Flabellina riwo from Reunion Island

December 10, 2009
From: Hugues Flodrops

Dear Bill,
Her is a Flabellina riwo, which is seldom seen on the fore reef zone.
This species was first found in Riwo Village, near Madang, Papua New Guinea.

We have any pictures of specimen from Le Cap La Houssaye.


Locality: Cap La Houssaye, 12 metres, Reunion Island, Indian Ocean, 17 september 2009. Length: 20 mm. Photographer: Hugues Flodrops.

I hope that information contribute knowing distribution of the species.

Best Regards.
Hugues.

hugues.flodrops@wanadoo.fr

Flodrops,H., 2009 (Dec 10) Flabellina riwo from Reunion Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22945

Thanks Hugues,

Although it was named from a village in Papua New Guinea, Gosliner & Willan (1991) also reported it from Indonesia, Okinawa and northern Madagascar. We also have records on the Forum from Japan, Malaysia and Indonesia, so it is clearly widespread in the Indo-West Pacific.

Your record from Reunion certainly fills in another gap in its recorded distribution, but from the records we now have I thik we can confidently predict it will be found throughout the tropical Indo-West Pacific.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Dec 10). Comment on Flabellina riwo from Reunion Island by Hugues Flodrops. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22945

Flabellina riwo from Sulawesi, Indonesia

September 10, 2005
From: Wendy Brown

Hello Bill,
Here is a picture of a nudibranch which I cannot seem to identify and wondered if you might be able to help. I am not even sure which family it is from. It was found in 10 metres of water at Wakatobi, Sulawesi, Indonesia on the 5th September. It was in a sandy rubble area and moving quite rapidly.

Locality: Wakatobi, Sulawesi, Indonesia, Banda Sea. Depth: 10 metres. Length: 1 inch. 5th September 2005. sandy rubble bay area. Photographer: Candy Armstrong

I really look forward to hearing from you
Kind regards
Wendy at Wakatobi

wendyfishface@hotmail.com

Brown, W., 2005 (Sep 10) Flabellina riwo from Sulawesi, Indonesia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/14716

Dear Wendy,
This is Flabellina riwo. It is nice to have some photos showing the colour pattern so clearly. Your animal sees to have been damaged - the back half seems to be regrowing.

Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Sep 10). Comment on Flabellina riwo from Sulawesi, Indonesia by Wendy Brown. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/14716

Flabellina riwo from Bali

August 23, 2005
From: Marli

Dear Bill,
I think this is Flabellini riwo. It was found at Kubu, which is 5 km. north of Tulamben.

Locality: Kubu, Bali, Indonesia.Depth: 40 feet. Length: 10 mm. 25 July 2005. silt covered rubble. Photographer: Marli Wakeling

Cheers,
Marli

scubamarli@gmail.com

Wakeling, M., 2005 (Aug 23) Flabellina riwo from Bali. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/14597

Thanks Marli,
Bill Rudman

Flabellina riwo from Tioman, Malaysia

April 16, 2005
From: Yuki Shigematsu

Hello Bill,

This tiny sea slug from Tioman looks like a juvenile Flabellina bilas for me though cerata looks a bit different. It was very small less than 1 cm. Can you identify this sea slug?

Locality: Tioman island, Malaysia, South China Sea. Depth: approx 15 m. Length: less than 10 mm. 25 March 05. Photographer: Yuki Shigematsu

Yuki Shigematsu

ikanhiu_same@hotmail.com

Shigematsu, Y., 2005 (Apr 16) Flabellina riwo from Tioman, Malaysia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13489

Dear Yuki,

Flabellina bilas, Flabellina bicolor and Flabellina riwo are three species of the genus with these chracteristic 'paddle-shaped' oral tentacles. The only species with the white reticulate pattern on the body and a purple band on the cerata, as in your animals, is Flabellina riwo. The original description of this species does not mention any yellow in the colour pattern but your photos, and others already on the Forum, show that it can have a yellow band on the cerata, above the purple one,  and can also have a yellow mark at least on the dorsal surface of the paddle-shaped tip to the oral tentacles.

Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Apr 16). Comment on Flabellina riwo from Tioman, Malaysia by Yuki Shigematsu. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13489

Flabellina riwo from Hachijo Is., Japan

July 31, 2002
From: Shouichi Kato

Dear Bill,
This animal was found on a rocky reef, 10m in depth. I sent this picture to Mr. Ono and he advised me this animal was Flabellina riwo. It was 35mm in size, characterized by its very large oral tentacles. Their motion was very interesting to me.

Best Regards,
S. Kato

regulus@edit.ne.jp

Kato, S., 2002 (Jul 31) Flabellina riwo from Hachijo Is., Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7668

Dear Shouichi,
I guess the oral tentacle motion you found interesting was the way it 'flaps' its paddle-like oral tentacles up and down as it crawls along. As I mentioned in an earlier message, this species and Flabellina bicolor both have this behaviour, but I have never seen anyone else ever mention seeing it. I am glad someone else has now reported it as I was beginning to wonder if I had dreamed it.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Jul 31). Comment on Flabellina riwo from Hachijo Is., Japan by Shouichi Kato. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7668

Flabellina riwo from SE Sulawesi, Indonesia

April 9, 2001
From: Lindsay Warren

Dear Bill
Some time ago you asked if someone might have a shot of Flabellina riwo showing it in more detail. I hope the shot I have attached helps. I found
this specimen (OS0732) on 24 August 1999 at 9.40 am on Pulau Kaledupa, Tukang Besi Archipelago, SE Sulawesi at a depth of 45 ft on a rubble slope crawling over coralline algae. Size: 14 mm. [Operation Wallacea] Photo: Lindsay Warren.

All the best
Lindsay

alldcl@compuserve.com

Warren, L, 2001 (Apr 9) Flabellina riwo from SE Sulawesi, Indonesia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4131

Dear Lindsay,
Thanks for the photo. I've included two enlargements as well to show the colour pattern of the head and cerata. A good photo is definitely worth a thousand words.
Thanks,
Bill Rudman

Rudman, W.B., 2001 (Apr 9). Comment on Flabellina riwo from SE Sulawesi, Indonesia by Lindsay Warren. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4131

Flabellina riwo from Papua New Guinea

July 15, 1999
From: Grey McNeil

Dear Bill,
Could you identify this photo please. The details are:
RASCHS REEF, MADANG, Papua New Guinea, 7m, December 1998, 1cm long alive.

Thanks,

Grey McNeil.

GREYMACIND@bigpond.com.au

McNeil, G., 1999 (Jul 15) Flabellina riwo from Papua New Guinea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1002

Dear Grey,
This is Flabellina riwo. Not a lot to say about it except that it seems to be one of the species of Flabellina with large flattened oral tentacles as in Flabellina bicolor, which tend to test the path as the slug moves along by 'flapping' the paddle-like tentacles on the substrate.

Bill Rudman.

Rudman, W.B., 1999 (Jul 15). Comment on Flabellina riwo from Papua New Guinea by Grey McNeil. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1002