Okenia elegans
(Leuckart, 1828)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: ANADORIDOIDEA
Family: Goniodorididae

DISTRIBUTION

Known from the western Mediterranean and the Bay of Biscay, although there are a few records from the southern North Sea. According to Thompson & Brown (1984) most British records are from the southwest coast of England.

PHOTO

St. Kilda, Outer Hebrides, in Scotland, June 1993, Photo: Daniel Geiger, [see message below.]

A relatively large species of Okenia with a relatively high profile and a mantle edge lened with papillae of varying sizes. Around the head there are up to eight quite long papillae, the anterior pair being eaqual in length to the rhinophores. Down the side of the body there are eight to ten short papillae on each side, quite crowded together, and a similar number form a border around the gills. There are also a few short papillae spaced irregularly in the dorsal midline between the gills and the rhinophores. The rhinophores are quite long and there are about twenty gills.

This species is quite spectaculalry coloured. The background colour of the body is usually a translucent white but it can be suffused with pink and in rare cases almost red in colour. The lateral papillae range in colour in different animals and different parts of the same animal from all yellow, to yellow tips and nases with a red or orange midregion, and sometimes with a white tip. The rhinophores are with a red ot pinkish band just below the tip. The gills are translucent white with varying degrees of pinkish or red colouration. There is a yellow or orange band around the edge of the foot.

This species is reported by various authors to feed on ascidians such as Molgula, Ciona, Dendrodoa grossularia and Polycarpa rustica, i nto which it burrows, and remains concealed, during much of its life. Can grow to 8 cm long.

  • Leuckart, F.S. (1828). Breves Anim. p.15, unnumbered plate, figs 2a-b.
  • Picton, B. E. & Morrow, C.C., 1994. A Field Guide to the Nudibranchs of the British Isles. London: Immel Publishing Ltd.
  • Thompson, T. E. & Brown, G. H., 1976. British Opisthobranch Molluscs. Synopses of the British Fauna (New Series)  The Linnean Society of London. London: Academic Press. [Synopses of the British Fauna, no. 8.]
Authorship details
Rudman, W.B., 2007 (July 26) Okenia elegans (Leuckart, 1828). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/okeneleg

Related messages


Okenia elegans sighting from Nth Wales

July 31, 2007
From: Tony Gilbert


Dear Bill,

My buddy Maureen Collins spotted this whilst out diving a great site in North Wales, UK. It was at the end of the dive, and she just chanced upon it. Luckily I was there to shoot some images.

Locality: Dive Site: Isolated Rock Maen Bugail in Bardsey Sound, Bardsey Island (Ynys Enlli)/Lleyn Peninsula. Nearest village/town: Aberdaron, Lleyn Peninsula, North Wales, United Kingdom. Lat: 52:46:24N (52.773333°) Lon: 4:47:25W (4.790278°), 8metres, North Wales, United Kingdom, Irish Sea, 08-July-2007 1100GMT/UTC, Located on red algae weed, which was on hard substrate ledge. Depth 8m. NW quadrant of rock. 1 specimen clinging to a weed frond, in some surge. Conditions: Slack Tide, Full Sunshine, Vis: 15m, surge.. Length: 5 centimetres. Photographer: Tony Gilbert

Regards
Tony.

TonyJGilbert@hotmail.com

Gilbert, A.J., 2007 (Jul 31) Okenia elegans sighting from Nth Wales. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20328

Dear Tony,
Thanks for this record.  This species is apparently quite rare in the British Isles and your animal seem to be a particularly brightly coloured example.

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Jul 31). Comment on Okenia elegans sighting from Nth Wales by Tony Gilbert. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20328

Okenia elegans from Scotland

December 20, 2000
From: Daniel L. Geiger

Hi Bill,

I wanted to mention for a long time an additional record and range extension for the European Okenia elegans. I photographed it in St. Kilda, Outer Hebrides, in Scotland, June 1993. [Dun, Village Bay in 15m water on a vertical wall covered in Bugula type bryozoans].

The find has been published in:
Ellis, J. R., P. S. Cadman, S. B. Piertney & D. L. Geiger, 1995. The marine fauna of the St. Kilda archipelago (Outer Hebrides). Scottish Naturalist, 107: 53-70.

It may have escaped the nudibranch radar screen of many people.

Best wishes
Daniel

dgeiger@nhm.org

Geiger, D.L., 2000 (Dec 20) Okenia elegans from Scotland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3310

Thanks Daniel,
Bill Rudman.