Okenia japonica from Hong Kong

August 17, 2001
From: Bill Rudman & Brian Darvell

Here is some information and photos on Okenia japonica from Brian Darvell's Hong Kong collections.

This small elongate species of Okenia has small rounded papillae along each edge of the mantle. The mantle edge and the papillae are usually pigmented white, and there is a white band along the edge of each gill, but the rest of the body is a translucent whitish colour devoid of pigmentation. This species, up to 8 mm long, has been found on encrusting bryozoans.

PHOTO: 3 specimens, 14 April 1983, Site 2.66, Round Is. (W), Mirs Bay, 3-6 m, AM C139013. Upper Photo: inset showing spiculate mantle - Photo: B.W. Darvell.

Hong Kong Collection Records:
AM C133749,21 March 1982, Site 1.20, Village Rock, Double Haven, 10 m. AM C139013, 3 specimens, 14 April 1983, Site 2.66, Round Is. (W), Mirs Bay, 3-6 m. AM C139014, 11 April 1983, Site 4.60, Kong Chau (NW), Mirs Bay, 5-10 m. AM C141478, 11 February 1984, Site 10.98, Kiu Tau (S), Kiu Tsui Chan, Port Shelter, 4 m. AM C150245, 2 specimens, 5 April 1986, Site 2.67, Kai Kung Tau, Kat O Chau, Mirs Bay, 6 m. AM C150246, 2 specimens, 20 April 1986, Site 2.173, Kat O Chau (E of E tip), Mirs Bay, 2 m. Depth range: 2-12 m.

Reference:
• Rudman, W.B. & Darvell, B.W. (1990) Opisthobranch molluscs of Hong Kong. Part 1. Goniodorididae, Onchidorididae, Triophidae, Gymnodorididae, Chromodorididae, (Nudibranchia). Asian Marine Biology, 7: 31-79

Best wishes,
Bill Rudman & Brian Darvell

Rudman, W.B. & Darvell, B.W., 2001 (Aug 17) Okenia japonica from Hong Kong. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5070

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