Selection: Okenia liklik

Okenia liklik Gosliner, 2004

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Okenia liklik is characterized by its uniform translucent purplish-pink colour, and by the broad band of alternating opaque white and brown patches down the dorsal midline of the mantle. It has 8-9 pairs of lateral papillae at the mantle edge. The rhinophores are relatively large, translucent brown, with a diffuse yellowish spot near the tips. There is a rounded crest in the dorsal midline, just in front of the gills. This specimen differs in many points from the description of Okenia liklik:
- by the colour of the lateral papillae,
- by the number and by the colour of the pairs of long anterior papillae which are directed anteriorly,
- by the number and by the colour of the pairs of long posterior papillae,
- by the colour of the gills, and
- by the colour of the middorsal crest.
Maybe I should label this specimen Okenia cf. liklik!
in Okenia liklik are:
- the lateral papillae pinkish purple with a subapical orange band and usually a brown tip,
- the 2 pairs of most anterior papillae very long, anteriorly directed, located in front of the rhinophores, and orange with brown apices,
- the pair of most posterior papillae is very long, translucent purplish-pink,
- the gills opaque white,
- the rounded crest in the dorsal midline pinkish is purple-red,
in this specimen are:
- the lateral papillae whitish-cream, - the 2 (!) pairs of most posterior papillae very long, translucent purplish pink with white apices,
- the gills translucent purplish pink with orange apices,
- the rounded crest in the dorsal midline is opaque white.
Okenia liklik was described by Gosliner at the base of 3 specimens, 2 from Papua New Guinea, and 1 specimen from Luzon Island in the Philippines. Its name refers to the small size of this species. "liklik is Papuan Pidgin for the word "small," Gosliner writes:"The living animals are small, 3-4 mm in length."
I think this specimen is a variant of Okenia liklik, because of the distictive broad band of alternating opaque white and brown patches down the dorsal midline, and because of the translucent purplish-pink colour.
There is a picture taken by Brian Mayes of a very similar specimen from Tulamben, Bali, Indonesia as Opisthobranch of the Week 26 October 2009 at Michael D. Miller's Slug Site. Let me quote David W. Behrens:" Brian's specimen here suggests greater variation in color patterns than that described by Gosliner (2004)."
Reference:
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.
The original description is online at PCAS Volume 55.
More informations on Okenia liklik are at Bill Rudman's Sea-Slug Forum!