Okenia pellucida
Burn, 1967

Suborder: DORIDINA
Family: Goniodorididae


New Zealand, Australia (NSW, Qld,  WA), Hawaii, Japan, Palmyra Atoll,  Malaysia; United Arab Emirates  (See Rudman, 2004).


Angourie, North Coast, New South Wales, Australia. March 1982, 3 specimens 8, 12 & 20mm long, on Zoobotryon. PHOTOS: Bill Rudman.

The animal is elongate with up to 11 or 12 lateral papillae along each side of the mantle edge, which forms a distinct ridge around the edge of the notum. There are also a few papillae [5-6] on the dorsum, but they do not seem to form a consistent pattern. The head is quite separate from the foot and bears large triangular oral tentacles. The rhinophores are about twice the length of the mantle papillae. The gills are bipinnate and form a circle, or incomplete arch around the anal papilla.

The whole of the body is translucent white with a network pattern of thin dark brown lines covering all parts of the dorsum, the foot,  the head and the rhinophores stalk.  In some specimens the lines also extend to the tips of the mantle papillae. There is often a brownish band around the bottom half of the rhinophore club, and the gills have a thin brown line along each rachis.

The anatomy of this species has recently been re-examined (Gosliner, 2004; Rudman, 2004). Photos of the radula are posted separately [see message #12648 ]. Since its original discovery in Sydney Harbour 40 years ago, this species is now known from much of the Indo-West Pacific. It is always associated with the ctenostome bryozoan Zoobotryon verticillatum on which it feeds and lays its egg masses. This bryozoan is a common fouling organism which suggests that wide distribution of this nudibranch has probably been aided by shipping.

  • Burn, R. (1967). Descriptions of two new species of Okenia (Nudibranchia, Doridacea) from south-eastern Australia. Proceedings of the Royal Society of New South Wales 1965-66: 52-57.
  • Gosliner, T. M. (2004) Phylogenetic Systematics of Okenia, Sakishimaia, Hopkinsiella and Hopkinsia (Nudibranchia: Goniodorididae) with descriptions of new species from the tropical Indo-Pacific. Proceedings of the California Academy of Sciences, 55: 125-161.
  • Rudman, W.B. (2004) Further species of the opisthobranch genus Okenia (Nudibranchia: Goniodorididae) from the Indo-West Pacific. Zootaxa, 695: 1-70.

ARCHIVE NOTE:  An earlier edition of this Fact Sheet [5 Oct 1999] is available on request. 

Authorship details
Rudman, W.B., 2004 (December 21) Okenia pellucida Burn, 1967. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/okenpell

Related messages

  1. Okenia pellucida from Ratnagiri, India
    From: Vishal J. Bhave, April 25, 2010
  2. Re: Okenia pellucida from eastern Australia
    From: Leanne & David Atkinson, February 28, 2008
  3. Okenia pellucida from eastern Australia
    From: Leanne & David Atkinson, January 31, 2008
  4. Okenia pellucida from Lembeh,North Sulawesi
    From: Francis & Pirjo Pellet, June 4, 2007
  5. Radula of Okenia pellucida
    From: Bill Rudman, December 21, 2004
  6. Bryozoan food of Okenia pellucida
    From: D.& L. Atkinson, February 29, 2000
  7. Okenia pellucida from New South Wales
    From: D.& L. Atkinson, February 23, 2000
  8. Re: Okenia pellucida
    From: Tomohiko Kurihara, October 8, 1999
  9. First record of Okenia pellucida from Japan
    From: Tomohiko Kurihara, October 6, 1999

Show factsheet and all related messages