(Alder & Hancock, 1854)
Boreo-Arctic. Nth Atlantic: Known from east Greenland and southwards along the Nth American coast to southern Massachusetts, USA. Common around Iceland, Norway, the Baltic and south to the British Isles. Intertidal to 60m. Nth Pacific: From southern British Columbia, Canada to Sth Korea.
Strangford Lough, Co. Down, Northern Ireland, 28 April 2001. On bryozoan Electra pilosa. Photo: Bernard Picton.
Very similar in shape, colour variation, food and habitat to Onchidoris muricata. It grows to a larger size (17-25mm - compared to 12mm for O. muricata), and the mantle papillae taper to a slender rounded tip while in O. muricata they are flattened with projecting spicules.
It feeds preferentially on Electra pilosa which grows on brown algae, but will eat other encrusting bryozoans if necessary. Both species spawn from February to May (late winter, Spring) so only juveniles are present during Summer months. Differs from O. muricata in having larger eggs which hatch after approx 40 days into lecithotrophic non-feeding planktonic larvae.
Bleakney, J.S., (1996) Sea Slugs of Atlantic Canada and the Gulf of Maine
Millen, Sandra. (1987) The nudibranch genus Adalaria with a description of a new species from the northeastern Pacific. Canadian Journal of Zoology, 65: 2696-2702
Thompson, T.E. & Brown, G.H. (1984) Biology of Opisthobranch Molluscs, Vol 2. Ray Society: London.
Rudman, W.B., 2001 (July 5) Adalaria proxima (Alder & Hancock, 1854). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/adalprox
Re: Adalaria proxima egg coils
From: J. Hildering & G. Miller, November 10, 2007
Adalaria proxima egg coils
From: Jackie Hildering, February 20, 2007
Re: Korean Adalaria proxima
From: Sandra Millen, February 12, 2006
Re: Korean Adalaria proxima feeding
From: Jeff Goddard, February 12, 2006
Korean Adalaria proxima feeding
From: Dong Bum Koh, February 11, 2006
Re: Adalaria proxima? from British Columbia?
From: Jeff Goddard, October 9, 2003
Re: Adalaria proxima? from British Columbia
From: Alan Shepard, October 9, 2003
Adalaria proxima? from British Columbia
From: Marli Wakeling, October 6, 2003
Adalaria proxima from Newfoundland
From: Paulette Penton, March 23, 2003
Photos of Adalaria proxima
From: Bernard Picton , July 6, 2001