Runcinella zelandica
Odhner, 1924
Order: CEPHALASPIDEA
Superfamily: RUNCINOIDEA
Family: Runcinidae
DISTRIBUTION
Known only from north-eastern New Zealand
PHOTO
Poor Knights Ids, north-eastern New Zealand. Size 6mm, Depth 10m, January 2002. Photo: Gareth Jones
This small runcinid grows to about 6mm in length. Dark green background colour with a pattern of irregular thick salmon pink longitudinal bands. In some specimens there can also be some irregular white patches. The anterior corners of the head are folded into prominent tentacular processes which give the head a bilobed appearance. From Gareth Jones photos, the gills are extremely large and project out prominently from under the posterior end of the mantle.
Willan (1981) reports it being found on and apparently feeding on the alga Codium dichotomum. He reports that it is found at the Poor Knights Ids in regions of high water movement and high oxygenation, usually in the lower sublittoral fringe to about 3m, but can be found as deep as 15m.
Originally described from a few preserved animals collected at Cape Brett, Bay of Islands (Odhner, 1924), its external colour was only described quite recently (Willan, 1981) when it was rediscovered at the nearby Poor Knights Ids. Gareth Jones photos, are to my knowledge, only the third time this animal has been recorded.
References:
• Miller, M.C. & Rudman, W.B. (1968) Two new genera and species of the Superfamily Runcinoidea (Mollusca, Gastropoda, Opisthobranchia) from New Zealand. Transaction of the Royal Society of New Zealand (Zoology), 10(19): 183-9, 3 figs.
• Odhner, N.H. (1924) Papers from Dr. Th. Mortensen's Pacific expedition 1914-16. New Zealand Mollusca. Videnskabelige Meddeleser fra Danske Naturhistorisk Forening, 77: 1-90. (Pls.1-2)
• Willan, R.C. (1981) Rediscovery of Runcinella zelandica Odhner, 1924 (Opisthobranchia: Runcinacea). National Museum of New Zealand Records, 2(2): 5-8.
Rudman, W.B., 2002 (January 30) Runcinella zelandica Odhner, 1924. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/runczela
Related messages
Runcinella zelandica and others from New Zealand
February 10, 2005
From: Bill Rudman
On my recent trip to New Zealand, Michael Miller kindly lent me a set of slides of New Zealand opisthobranchs to fill in some gaps on the Forum. I will gradually scan and post them as I have time.
As a first offering I have prepared Fact Sheets for Pseudoilbia lineata Miller & Rudman, 1968 and Runnica katipoides Miller & Rudman, 1968. I have also included here a photo of Runcinella zelandica Odhner, 1924. This photo is of one of the animals reported by Willan (1981) which represented the first find of the species since its description in 1924. The only other record known to me is Gareth Jones' message [#6137 ] on the Forum.
Photo: Outside of middle archway Tawhiti Rahi Island. Poor Knights Ids. N.Z. 22 March 1975. Approx. 3 mm long alive. Photo: M.C. Miller [digitally enhanced by WBR]
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Willan, R.C. (1981) Rediscovery of Runcinella zelandica Odhner, 1924 (Opisthobranchia: Runcinacea). National Museum of New Zealand Records, 2(2): 5-8.
Best wishes,
Bill Rudman.
Rediscovery of Runcinella zelandica
February 1, 2002
From: Gareth Jones
Hello Dr. Rudman.
I photographed a nudibranch at the Poor Knights Ids [northeastern New Zealand] last week and would once more appreciate your help in identification.
Size 6mm, depth 10m, temp 18C. January 2002.
Regards
Gareth Jones
Pacific Hideaway
rees@divenz.co.nz
Jones, G., 2002 (Feb 1) Rediscovery of Runcinella zelandica. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6137Dear Gareth,
This is a very interesting find. It is Runcinella zelandica and to my knowledge this is only the second time it has been reported alive. Your photos are the first coloured photos of living animals to be published. It was originally collected on a Swedish expedition in 1914-16 at Cape Brett, Bay of Islands (Odhner, 1924), from preserved animals, and its external colour was unknown until Willan, (1981) rediscovered it at the nearby Poor Knights Ids.
Two interesting features in your photos are the way the anterior corners of the head are folded into pseudo-tentacles and the relatively large gills which stick out behind the posterior mantle. These are not features which we could see from preserved animals.
I spent many hours trying to find live specimens of this animal as a graduate student. I was studying Runnica katipoides, the common intertidal runcinid in New Zealand, which at that time was misidentified as Runcinella zelandica simply because it was the only species known from New Zealand. When Michael C. Miller and I looked at its anatomy it was very clear that it was not Odhner's species so we named it Runnica katipoides. We would have liked to have had some specimens of true Runcinella zelandica for comparative purposes but neither I nor Michael Miller, who had been studying the NZ fauna for many years, had ever found it. If it is indeed restricted to northeastern New Zealand it is a very strange distribution, so it would be useful to look out for it in other parts of New Zealand just so we have better idea of its range.
Unfortunately I don't have a photo of Runnica katipoides so if anyone has one to share it would be nice to include in the Forum for comparative purposes. It is often very common in coralline algal turf both intertidally and in the shallow sublittoral. It is black with a red stripe down its back.
• Miller, M.C. & Rudman, W.B. (1968) Two new genera and species of the Superfamily Runcinoidea (Mollusca, Gastropoda, Opisthobranchia) from New Zealand. Transaction of the Royal Society of New Zealand (Zoology), 10(19): 183-9, 3 figs.
• Odhner, N.H. (1924) Papers from Dr. Th. Mortensen's Pacific expedition 1914-16. New Zealand Mollusca. Videnskabelige Meddeleser fra Danske Naturhistorisk Forening, 77: 1-90. (Pls.1-2)
• Willan, R.C. (1981) Rediscovery of Runcinella zelandica Odhner, 1924 (Opisthobranchia: Runcinacea). National Museum of New Zealand Records, 2(2): 5-8.
Best wishes,
Bill Rudman
