Western Pacific - Japan to New Zealand
UPPER: Holotype of H. koumacensis, Grande Recif de Koumac, N Lagoon, New Caledonia, 45m, 32mm long preserved, 3 Nov 1980, (MNHN, Paris).
LOWER: Poor Knights Islands, NE New Zealand, 48m. April 2001. Photo: Ian Skipworth.
In 1995 I described a new species from New Caledonia as Hypselodoris koumacensis on the basis of a single specimen and photograph. Normally I do not describe species on the basis of single specimens but this was so unlike any described species I felt sure it was unnamed. Unfortunately Baba was also preparing a description for Hypselodoris kaname Baba, 1994, which seems to be the same species. Gosliner & Johnson, (1999) consider the two species to be closely related sister species with H. paulinae and H. fucata. H. kaname has been recorded from from Japan to Bali, Indonesia and reported in the Forum from New Zealand. I find it unlikely that Hypselodoris koumacensis, occurring within the range of H. kaname is a distinct species. There are some small differences in radular morphology and external colour. The radular differences concern where the small denticles appear on the lateral teeth. Until we have more specimens to examine we cannot say how significant those differences are. Concerning the colour differences, it seems the photograph of H. koumacensis was overexposed, and the orange brown lines and markings on the mantle were red. If that is so, then Hypselodoris koumacensis is identical in colour to H. kaname. Of the other two species Gosliner & Johnson consider related, H. fucata has only a vaguely similar colour pattern but H. paulinae is either the same species as H. kaname or a very closely related Hawaiian endemic. The main colour difference is that the red on the mantle is in the form of longitudinal streaks and spots rather than lines. Gosliner & Johnson say it lacks a submarginal purple mantle band but it seems the submarginal band in these species is better described as deep red except around the anterior end where it breaks into a series of purple spots. This is clearly seen in Scott Johnson's photos of H. paulinae from Hawaii and Ian Skipworth's of H. kaname from New Zealand. Another identical colour feature is the submarginal purple band on the foot. I feel that H. kaname and H. paulinae are either the same species or very closely related. Without further material I can't be 100% sure, but on the available evidence I feel sure that H. koumacensis is the same as H. kaname.
COLOUR: The mantle is a creamy white to light brown with a pair of irregular red lines which loop around and join together at the back of the gill pocket and anteriorly pass between the rhinophore pockets before joining in an anterior loop. There can also be a red line, or row of spots forming a line down each side of the mantle some distance in from the edge. There is a broad orange-yellow band at the mantle edge and inside this is a red or purplish band with deeper red patches scattered over it. At the anterior end the band moves away from the orange-yellow margin and appears as a row of deep purplish red spots. The rhinophores are red or orange and the translucent white gills are edged with red or orange. The foot is white with red spots or a line, and a diffuse purple submarginal band around the edge of the foot.
• Baba, K. (1995) Descriptions of four new rare or unrecorded species of Hypselodoris (Nudibranchia: Chromodorididae) from Japan. Venus (Jap. Journ. Malac), 53(3): 175-187
• Gosliner, T.M. & Johnson, R.F. (1999) Phylogeny of Hypselodoris (Nudibranchia: Chromodorididae) with a review of the monophyletic clade of Indo-Pacific species, including descriptions of twelve new species. Zoological Journal of the Linnean Society, 125: 1-114.
• Rudman, W.B. (1995) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: further species from New Caledonia and the Noumea romeri colour group.
Molluscan Research, 16: 1-43.
Rudman, W.B., 2001 (May 3) Hypselodoris kaname Baba, 1994. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/hypskana
Hypselodoris kaname from sthn Queensland, Australia
From: Bruce Wilkie, June 8, 2006
Hypselodoris kaname from Nth Sulawesi
From: Sergey Parinov, June 22, 2005
Hypselodoris kaname from North Sulawesi
From: Francis & Pirjo Pellet, February 16, 2005
Hypselodoris kaname from New Zealand
From: Ian Skipworth, May 11, 2001