Baeolidia japonica from Japan.

August 9, 2002
From: Jun Imamoto

Dear Bill.
I found this sea slug which looked like Berghia japonica. We found it after seeing in Opisthobranchia of Sagami Bay by Kikutaro Baba, that it had been found in very shallow water. We thought that we couldn't find it by Scuba-Diving, so my wife and I looked in very shallow water and my wife found a pair of these sea slugs under a stone. So we think it is probably not uncommon at this place. I would be very happy if I could hear your comment.

date: 27 July 2002
place: Osezaki, Izu Peninsula, Suruga bay, Japan
size about: 10mm
depth: 2m
temperature: 26 C

Best Regards,
Jun Imamoto

Imamoto, J., 2002 (Aug 9) Baeolidia japonica from Japan.. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Jun,
Another interesting find as there seem to be very few records of this species. Your photo certainly looks more like the painting in Baba (1949) than Atsushi Ono's photos from Kerama Id. which I first thought were a species of Limenandra. The blue markings on the inside of the cerata in both yours and his photos show that his animals are almost certainly B. japonica as well. The brown network, presumably ducts of the digestive gland can be clearly seen on the sides of the body and the head. This suggests that the species may also be solar powered, storing, or keeping alive, zooxanthellae in its tissues.

One problem is what genus this species should be placed in. Baba described it as Baeolidia japonica, and it is has been transferred to Spurilla and Berghia at various times since then. If we follow Miller's (2001) recent review of the family, the most appropriate place seems to be back in Baeolidia.

• Miller, M.C. (2001) Aeolid nudibranchs (Gastropoda: Opisthobranchia) of the family Aeolidiidae from New Zealand waters. Journal of Natural History, 35: 629-662.

Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Aug 9). Comment on Baeolidia japonica from Japan. by Jun Imamoto. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Baeolidia japonica

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