Dermatobranchus pulcherrimus from New Zealand
November 1, 2002
From: Clinton Duffy
Dear Bill,
I recently collected what to my eye was an unusual nudibranch in a grab sample from soft mud, 15 m depth, off Colville Bay, inner Hauraki Gulf, east coast of nthn New Zealand. After perusing a couple of nudibranch sites it appears to be a species of Dermatobranchus.
It was 30 mm long when crawling, red with fine longitudinal white lines, a broad white margin to the front of the foot and small dark red rhinophores. When crawling the foot behind the rhinophores was expanded into a small "wing" on either side of the body, before tapering rapidly to the "tail". I have taken a rather poor photograph of the live animal in a dish (no macro lens unfortunately). There was no epifauna in the grab and the animal's gut, visible through the body wall, appeared to be full. All in all an unusual little animal. I was particularly interested in Leanne Atkinson's observations of spawning in Armina, as a week or so earlier we collected a mysterious gelatinous mass that resembles the egg mass in her photos.
Station details: Inner Hauraki Gulf Survey: Station 6C Lat 36 37.57 S Long 175 23.97 E Depth 15.3 metres. 8 October 2002. Substrate Description: Surface layer of very soft brown mud with shell fragments. Firmer grey clay underneath. As in most other parts of the Gulf that we have surveyed, a video transect of the sea floor at this site suggested it was devoid of epifauna.
Regards
Clinton
Clinton Duffy
Scientific Officer (Marine Ecology)
Department of Conservation
Hamilton, New Zealand
cduffy@doc.govt.nz
Duffy, C., 2002 (Nov 1) Dermatobranchus pulcherrimus from New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/8254Dear Clinton,
There are only a few of arminids reported from New Zealand, [Armina aoteana Miller & Willan, 1986, Dermatobranchus pulcherrimus Miller & Willan, 1986 and Heterodoris antipodes Willan, 1981] and your animal clearly fits the description of Dermatobranchus pulcherrimus Miller & Willan, 1986. It is easily distinguishable by its reddish colour, the tentacular extensions of the oral veil, the broad foot, and the enlarged leading edge of the foot which is developed into a large semicircular structure with tentacular foot corners. One slight difference is that in the original description, the longitudinal ridges and the edges of the foot, oral veil and mantle are described as opaque white, while in your animal they appear to be translucent clear. I don't know if that suggests some variability in the amount of white pigmentation present in this species or perhaps that you animal was not in the best state when photographed.
It is certainly good to get a further record from New Zealand. It has previously known from New Zealand by two specimens, one from the Colville Channel, outer Hauraki Gulf, and the other from Whangarei Harbour. We know nothing about its biology.
Reference:
• Miller, M.C. & Willan, R.C. (1986) A review of the New Zealand arminacean nudibranchs (Opisthobranchia: Arminacea). New Zealand Journal of Zoology, 13: 377-408.
Best wishes,
Bill Rudman
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