Known only from north-eastern New Zealand
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.
• 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/factsheet/runczela