Kaloplocamus cf. ramosus from Hong Kong

February 5, 2002
From: Bill Rudman & Brian Darvell

Here is some information and photos on Kaloplocamus cf. ramosus from Brian Darvell's Hong Kong collections.

Similar to Kaloplocamus acutus in shape but body is translucent white with some brownish shading and many reddish brown or reddish orange spots. There are some white specks and small white papillae on the sides of the body. This colour form is illustrated from Japan (Baba 1949, pl. 13, fig. 47). Another colour form illustrated by Baba (pl. 13, fig. 46) is of a vivid orange body with minute spots of chocolate on the back and sides. Most authors identify the Japanese species with K. ramosus from the Mediterranean. Unfortunately there is considerable difference in radular morphology between K. ramosus as described by Schmekel and Portmann and K. croceus described by Vayssiere, 1901. Until more is known of material from the Mediterranean the correct identity of these specimens from the NW Pacific will be difficult to determine. Another uncertainty is the relationship of these species to a very similar species or pair of species from southeastern Australia, which seem to have a similar range of colour to that illustrated by Baba (1949) from Japan. The Australian specimens, or at least those with an orange background colour, can be identified with Kaloplocamus yatesi (Angas 1864). If the Mediterranean and Indo-West Pacific species prove to be a single species then the name K. ramosus would clearly take precedence but if not then careful consideration would have to be given to the relationship between the Japanese and Australian species for K. yatesi is clearly the oldest name for an Indo-West Pacific species. This species, which can grow to 4 cm in length, feeds on encrusting bryozoans. The largest Hong Kong specimen has a preserved length of 20 mm.

PHOTO:
UPPER RIGHT: AM C141492, 13 specimens, 25 February 1984, Site 10.99, Kiu Tau (W), Kiu Tsui Chau, Port Shelter, 4-7 m. LOWER LEFT: AM C141493, 24 February 1984, Site 14.41, Tai Tam Harbour, Hong Kong Is., 0.5 m. LOWER RIGHT: AM C 139130, 11 specimens, 11 April 1983, Site 4.59, Gau Tau (N), Mirs Bay, 5-12 m. PHOTOS: Brian Darvell.

Hong Kong Collection Records:
AM C 139130, 11 specimens, 11 April 1983, Site 4.59, Gau Tau (N), Mirs Bay, 5-12 m. AM C139131, 11 April 1983, Site 4.60, Kong Chau (NW), Mirs Bay, 5-10 m. AM C139132, 13 April 1983, Site 4.65, Chek Chau (NE), Mirs Bay, 2-6 m. AM C139133, 4 specimens, 14 April 1983, Site 2.32, Round Is. (E), Mirs Bay, 3-10 m. AM C139134, 2 specimens, 14 April 1983, Site 2.66, Round Is. (W), Mirs Bay, 3-6 m. AM C139135, 2 specimens, 15 April 1983, Site 2.67, Kai Kung Tau, Kat 0 Chau, Mirs Bay, 5-10 m. AM C139136, 19 April 1983, Site 4.8, Breaker Reef, Mirs Bay, 5-16 m. AM C 141482, 22 January 1984, Site 13.96, Shum Wan (W), Lamma Is., 6 m. AM C141492, 13 specimens, 25 February 1984, Site 10.99, Kiu Tau (W), Kiu Tsui Chau, Port Shelter, 4-7 m. AM C141493, 24 February 1984, Site 14.41, Tai Tam Harbour, Hong Kong Is., 0.5 m. AM C142183, 31 March 1984, Site 10.99, Kiu Tau (W), Kiu Tsui Chan, Port Shelter, 4 m. AM C150283, 5 April 1986, Site 5.128, Heung Lo Po (E), Tolo Channel, 2 m. Depth range: 0.5-16 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., 2002 (Feb 5) Kaloplocamus cf. ramosus from Hong Kong. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6026

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