Doriopsis pecten
(Collingwood, 1881)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Dorididae

DISTRIBUTION

Indo-West Pacific

PHOTO

Upper & Lower Right: Koumac Beach (=Baie de Ouanap), near Koumac, New Caledonia, 27 October 1993, 7mm long alive (blue), AM C200674.
Lower Left: Îlot Freycinet, Nouméa, 1m, 23 October 1988, AM C156676, 11mm long alive, on deep blue sponge. Photos: Bill Rudman

Species of Doriopsis are characterised by the arrangement of the gills in a transverse line across the back rather than in the typical dorid circle. There is a dorsal flap covering the gill opening. D. pecten has small rounded tubercles over the mantle. The mantle is blue, sometimes so dark are to appear almost black, and in the raised central region is usually paler, almost translucent in colour, with a criss-cross pattern caused by the underlying spicules in the skin. It is often found feeding on a deep blue sponge, Terpios.

Specimens of Doriopsis are either deep blue, green or yellow and there has been considerable confusion in the literature concerning how many species there are in the genus. At one extreme 4 species, one each of green and blue and two of yellow have been suggested, while at the other extreme only one variably coloured species has been proposed.

Biological observations from throughout the Pacific suggest that there are at least two species, one yellow or green and one deep blue. It is also possible that the yellow New Zealand species, Doriopsis flabellifera Cheeseman, 1881, is a third valid species. The earliest name for the yellow/green species is D. granulosa and for the blue, D. pecten. Reports from Hawaii (Kay & Young, 1969; Bertsch & Johnson,1981), Japan (Hamatani, 1961, Baba & Hamatani, 1961), and the central Pacific (Young, 1967; Johnson, 1981) show that D. pecten feeds exclusively on a deep blue sponge Terpios, and D. granulosa on a yellow or orange sponge, identified by Young (1967) as Prianos phlox de Laubenfels, 1954. The eggs of D. granulosa are reported to be yellow, while those of D. pecten are cream, and the egg ribbon of D. granulosa is about four times as wide as that of D. pecten. The green 'species' or 'form' has often been named Doriopsis viridis Pease, 1861.

Reference:
• Baba, K. & Hamatani, I., 1961. On two new species of Doriopsis (syn. Ctenodoris) from Japan (Nudibranchia - Dorididae). Publications of the Seto Marine Biological Laboratory, 9: 63-65.
• Bertsch, H. & Johnson, S., 1981. Hawaiian Nudibranchs. Honolulu: Oriental Publishing Co.
• Collingwood, C. (1881). On some new species of nudibranchiate mollusca from the Eastern Seas. Transactions of the Linnean Society, London, Zoology, 2: 123-140, Pls 9-10.
• Hamatani, I., 1961. Notes on veligers of Japanese opisthobranchs (4). Publications of the Seto Marine Biological Laboratory, 9(2): 353-361.
• Johnson, S., 1981. Blue camouflage in a nudibranch. Hawaiian Shell News, 29(6): 14.
• Kay, E.A. & Young, D.K., 1969. The Doridacea (Opisthobranchia: Mollusca) of the Hawaiian Islands. Pacific Science, 23: 172-231.
• Pease, W.H. (1860). Descriptions of new species of mollusca from the Sandwich Islands. Proceedings of the Zoological Society of London, 28: 18-37.
• Young, D.K., 1967. New records of Nudibranchia from the Central and West-Central Pacific with a description of a new species. The Veliger, 10: 159-173.

Authorship details
Rudman, W.B., 2003 (March 6) Doriopsis pecten (Collingwood, 1881). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/doripect

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