Opisthobranchs of Hong Kong

Collingwood, (1881) provided the first and only account of opisthobranchs from the South China Sea until the publication of limited checklists on the fauna by Orr (1980) and Tsi & Ma (1982), and a book (Orr 1981), illustrating 54 species in colour. Despite misidentifications in these publications they were valuable indications of the richness of the fauna. The nearest regional account (Lin and Tchang 1965) records 60 opisthobranch species from the coast of Hainan Island and the surrounding South China Sea and with further papers (Lin 1975; 1981; 1986), provide us with a good account of the opisthobranch fauna of the southern Chinese coast. Further afield, though clearly related to the Hong Kong fauna, the nudibranch fauna of Japan has been the subject of exhaustive and diligent studies by Dr K. Baba and his colleagues since 1930.

In the 1980s Brian Darvell made an extensive collection of nudibranchs and other opisthobranchs from Hong Kong. These specimens and accompanying colour photographs have been deposited in the collections of the Australian Museum, Sydney, where they are being identified and used in taxonomic and anatomical studies by Bill Rudman. Over 230 species were collected. A paper covering 46 species from the dorid families Goniodorididae, Onchidorididae, Polyceridae (Triophinae), Gymnodorididae and Chromodorididae was published in 1990 (Rudman & Darvell, 1990).

Brian Darvell and I have decided to use the Forum to publish descriptions and photos of as many of the species in the collection as possible, starting with those covered in the 1990 publication.

The specimens were collected between late 1981 and August 1988. Although some intertidal collections were made, most specimens were collected sublittorally by scuba. As well as the personal collecting of Brian Darvell, the collections were supplemented over the 7 years by specimens collected by resident members of the South China Diving Club and by collections made by visiting participants to International Workshops in 1983 & 1986 organized by Professor B. Morton of the University of Hong Kong.

Collected specimens were usually photographed before preservation. In addition to collecting specimens, field notes were taken to record the seasonal occurrence of the more common species and their range of localities in the Hong Kong region. No standard collecting regime was implemented for such a survey would require resources far beyond those available. Despite this, the length of time for which records are available, and their spread both geographically and throughout the year, provide useful background information on the biology of individual species. All material is housed in the collections of the Australian Museum, Sydney.

Bill Rudman

• Collingwood, C. (1881). On some new species of nudibranchiate Mollusca from the Eastern Seas. Transactions of the Linnean Society of London (Series 2, Zoology). 2: 123-40, pls. 9-10.
• Jensen, K.R. (1985) Annotated checklist of Hong Kong Ascoglossa (Mollusca: Opisthobranchia), with descriptions of four new species. In: Proceedings of the 2nd International Workshop on the Malacofauna of Hong Kong and Southern China, Hong Kong, 1983. (Eds: Morton,B; Dudgeon,D) Hong Kong University Press, Hong Kong, 77-107.
• Jensen, K.R. (1998) Zoogeographic Affinities of Hong Kong Opisthobranchia (Mollusca, Gastropoda). In: The Marine Biology of the South China Sea. Proceedings of the Third International Conference on the Marine Biology of the South China Sea, Hong Kong. (Ed: B,Morton) Hong Kong University Press, Hong Kong, 43-55.
• Lim, C. F. & Chou, L. M. (1970). The nudibranchs of Singapore, excluding the families Dendrodoridae and Dorididae. Malayan Nature Journal, 23: 131-42.
• Lin, G. Y. (1975) Opisthobranchia from the Intertidal zone of Xisha Islands, Guangdong Province, China. Studia Marina Sinica, 10: 141-54, pls. 1-2.
• Lin, G. Y. 1981. A study of the family Arminidae (Opisthobranchia) of the China coast. Studia Marina Sinica. 18: 181-206, pl. 1.
• Lin, G. Y. 1986. Additions to the Opisthobranch Fauna of the Hainan and Xisha Islands of China. Studia Marina Sinica. 26: 117-28, pls. 1-2.
• Lin, G. Y. and Tchang, S. 1965. Opisthobranchia from the intertidal zone of Hainan Island, China. Oceanologia et Limnologia Sinica. 7: 1-20, pls. 1-3.
• Orr, J. (1980). Annotated checklist of Hong Kong nudibranchs. In Proceedings of the First International Workshop on the Malacofauna of Hong Kong and Southern China, Hong Kong, 1977. (Ed. Morton, B.). Hong Kong University Press, Hong Kong, pp. 109-17.
• Orr, J. (1981). Hong Kong Nudibranchs. Urban Council, Hong Kong.
• Rudman, W.B. & Darvell, BW. (1990) Opisthobranch molluscs of Hong Kong: Part 1. Goniodorididae, Onchidorididae, Triophidae, Gymnodorididae, Chromodorididae (Nudibranchia). Asian Marine Biology, 7: 31-79
• Tsi, C. Y. and Ma, S. T. 1982. A preliminary checklist of the marine Gastropoda and Bivalvia (Mollusca) of Hong Kong and Southern China. In Proceedings of the First International Marine Biological Workshop: The Marine Flora and Fauna of Hong Kong and Southern China, Hong Kong, 1980. (Eds. Morton, B. and Tseng, C. K.). Hong Kong University Press, Hong Kong, pp. 431-58.

Authorship details
Rudman, W.B., 2000 (June 23) Opisthobranchs of Hong Kong. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/hongkong