Thuridilla undula
Gosliner, 1995

Order: SACOGLOSSA
Superfamily: ELYSIOIDEA
Family: Elysiidae

DISTRIBUTION

Papua New Guinea, Guam, Palau, the Philippines and the Maldives

PHOTO

near Honiara, Solomon Islands, 8m. June 2001. Photo: Bruce Potter.

Living animals are turquoise bluish green. The parapodial margin is a burnt orange colour. Below that is a narrow line of black followed by a region of vivid blue pigment. This black and blue pigment is also on the head and the mid region of the rhinophores. The tips of the rhinophores are orange while the base are the same turquoise blue-green of the body. Orange, black and blue bands are also present on the anterior margins of the foot. T. undula is similar in colour to T. neona Gosliner, 1995. Both have a turquoise body with burnt orange, black and blue undulating parapodial bands. However T. neona has additional bright orange markings on the parapodia, anterior margin of the foot and the rhinophores. In T. undula the orange, blue and black markings on the rhinophores are transverse bands, while in T. neona they are diagonal. T. undula is even closer in colour to T. lineolata (Bergh, 1905), the main difference being that the colour bands at the parapodial edge undulate in T. undula and are parallel to the edge in T. lineolata. Gosliner reports that the two species differ in the branching of the veins off the pericardium, highly branched in T. undula and only bifurcating in T. lineolata.

See Thuridilla coerulea for comparison with the similarly coloured T. undula and T. lineolata.

  • Gosliner, T.M. (1995) The genus Thuridilla (Opisthobranchia: Elysiidae) from the tropical Indo-Pacific, with a revision of their phylogeny and systematics of the Elysiidae. Proceedings of the California Academy of Sciences, 49(1): 1-54.
Authorship details
Rudman, W.B., 2001 (June 9) Thuridilla undula Gosliner, 1995. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/thurundu

Related messages


Re: Thuridilla undula from Bali

January 17, 2006
From: Erwin Kodiat

Concerning message #15370:

Hi Bill,
This is another Thuridilla undula picture, it was taken at Padang Bai, Bali.

Locality: Ferry Channel, Padang Bai, Amuk Bay. Bali, Indonesia. Depth: 17 meters. Length: 2 cm. 26 November 2005. Slope. Photographer: Erwin Kodiat

Erwin Kodiat

ungu@terong.com

Kodiat, E., 2006 (Jan 17) Re: Thuridilla undula from Bali. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15562

Thanks Erwin,
Bill Rudman

Thuridilla undula from Karang Koka, Banda Sea

November 29, 2005
From: Linda Ianniello

We found two Thuridilla undula on Karang Koka Island, off SE Sulawesi, which I believe expands its range. Here is a shot of one of them.

Locality: Seletan dive site, Karang Koka Island, SE Sulawesi, Indonesia, Banda Sea. 8 November, 2005. Coral wall. Photographer: Linda Ianniello

Regards,
Linda I.

lindai1@bellsouth.net

Ianniello, L., 2005 (Nov 29) Thuridilla undula from Karang Koka, Banda Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15370

Dear Linda,
It's nice to be able to fill in a gap in its distribution
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Nov 29). Comment on Thuridilla undula from Karang Koka, Banda Sea by Linda Ianniello. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15370

Re: Thuridilla undula from Karang Koka, Banda Sea

November 29, 2005
From: Roberto Sozzani

Dear Bill,
Following Linda Ianniello's message [#15370] I've found a photo of a Thuridilla undula from Manado, North Sulawesi, to fill the gap a little bit more.

Locality: Manado, Indonesia. Depth: 12 metres. Length: 8-10 mm. June 2003. muddy with some corals. Photographer: Roberto Sozzani

Best wishes
Roberto Sozzani
www.robertosozzani.it

roberto.sozzani@fastwebnet.it

Sozzani, R., 2005 (Nov 29) Re: Thuridilla undula from Karang Koka, Banda Sea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15385

Dear Roberto,
Thanks for the quick response. It certainly looks dwarfed between the ascidians
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Nov 29). Comment on Re: Thuridilla undula from Karang Koka, Banda Sea by Roberto Sozzani. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15385

Thuridilla undula from the Solomon Ids

June 14, 2001
From: Bruce Potter


Bill,
Here is a small slug that I found yesterday. It was about 15mm long. I found it at about 8 meters on a rubble site just outside of Honiara in Solomon Islands. I cannot find it in your species list, but it looks like one identified by Debelius as Thuridilla undula. Do you agree.
I am having problems with my computer, so the image is not the best.
Regards
Bruce Potter.

bruce.potter@adventist.org.sb

Potter, B., 2001 (Jun 14) Thuridilla undula from the Solomon Ids. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4505

Dear Bruce,
Yes this is Thuridilla undula, another species which hasn't until now made the Forum.
Best wishes,
Bill Rudman

Rudman, W.B., 2001 (Jun 14). Comment on Thuridilla undula from the Solomon Ids by Bruce Potter. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4505