Eubranchus rupium
(Moller, 1842)

Family: Eubranchidae


As E. rupium it is known from Greenland, Denmark, Sweden, Norway. Reported here from the Netherlands and eastern North America. As E. olivaceus known from west coast of Nth America.


Texel, the Netherlands, 8 May 1987. PHOTO: Rob Dekker.

Grows to about 12mm. It preys upon the calyptoblastic hydroid Laomedea longissima.
See Rob Dekker's message, and photo of egg masses, below.

Martynov (1998) considers that E. olivaceus from the northeast Pacific is a synonym of E. rupium from the north Atlantic. Lemche, as described in Just & Edmunds (1985:114), also considered E. olivaceus and E. rupium to be the same species. [see Jeff Goddard's message.]

• Bleakney, J.S. (1996) Sea slugs of Atlantic Canada and the Gulf of Maine. Nimbus Publishing and The Nova Scotia Museum. 216pp.
• Gould, A. A. 1870. Report on the Invertebrata of Massachusetts, published agreeably to an order of the legislature. Second edition, comprising the Mollusca. Edited By W. G. Binney, v + 524pp. pls. XVI-XXVII. [Nudibranchia pp. 225-253, pls. 16-22]. Boston: Wright & Binney, State Printers.
• Just, H. & Edmunds, M. (1985) North Atlantic Nudibranchs (Mollusca) seen by Henning Lemche. Ophelia, Supplement 2. 170pp.
• Lambert, W.J. (1991) Coexistence of hydroid-eating nudibranchs: recruitment and non-equalibrial patterns of occurrence. Journal of Molluscan Studies, 57(4), Supplement, T.E.Thompson Memorial Issue: 35-47.
• Martynov, A.V. (1998) Opisthobranch mollusks (Gastropoda: Opisthobranchia) of the family Eubranchidae: Taxonomy and two new species from the Sea Of Japan. Zoologicheskii Zhurnal, 77: 763-777.
• Meyer, K.B. (1971) Distribution and zoogeography of fourteen species of nudibranchs of northern New England and Nova Scotia. Veliger, 14(2): 137-152.
• O'Donoghue, C.H. (1922) Notes on the Nudibranchiate Mollusca from the Vancouver Island Region. III. Records of species and distribution. Transactions of the Royal Canadian Institute, Toronto, 14(1): 145-167.

Authorship details
Rudman, W.B., 2003 (July 14) Eubranchus rupium (Moller, 1842). [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Eubranchus olivaceus? from British Columbia
    From: Laura McLeod, March 5, 2008
  2. Eubranchus rupium? from British Columbia
    From: Clinton Bauder, September 12, 2007
  3. Eubranchus rupium with eggs
    From: John de Jong, May 22, 2006
  4. Re: Eubranchus olivaceus?
    From: Alan Shepard, May 30, 2003
  5. Eubranchus olivaceus? from Massachusetts
    From: Alan Shepard, May 28, 2003
  6. Eubranchus rupium from Holland
    From: Rob Dekker, September 10, 1999

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