Dermatobranchus otome
Baba, 1992

Suborder: ARMININA
Family: Arminidae


Upper: Futou, Suruga-bay, Japan, 15 Jun 2002, Size approx: 20mm, Depth: 5m. Photo: Kahoru Imamoto
Lower: Manazuru, Sagami-bay, Japan, 8 Dec 2002, Size approx: 10mm, Depth: 0.3m (Intertidal). Photo: Jun Imamoto.

Previously identified in Japan as Dermatobranchus striatus Van Hasselt, 1824. The body and foot are translucent white, and in adults the mantle has a brownish tinge. There are a series of longitudinal ridges which bear scattered black spots, each black spot being ringed by a brownish ocelli. About a third of the way down the mantle is a trnsverse, curved blackish band. The head shield is white and the rhinophotr clubs are bright orange-red, fading to a whitish tip. In juveniles, the brownish background colour is often absent on the mantle, and the ocelli surrounding each black spot, is proportionally larger, and translucent with a pinkish tinge, rather than brown.

• Baba, K. (1937) Opisthobranchia of Japan (II). J. Dept. Agric. Kyusyu Imp. Univ. 5(7): 289-344. (Pls.1-2) [as D. striatus]
• Baba, K. (1949) Opisthobranchia of Sagami Bay collected by His Majesty The Emperor of Japan. Iwanami Shoten, Tokyo. 194pp., 50 Pls. [as D. striatus]
• Baba, K. (1976) Two new species and five common or rare species of the genus Dermatobranchus from Japan (Nudibranchia: Arminoidea: Arminidae). The Veliger, 19(1): 4-12. [as D. striatus]
• Baba, K. (1992) Critical review of Dermatobranchus striatus van Hasselt 1824 (Nudibranchia: Arminidae) with the description of a new species. Venus, The Japanese Journal of Malacology, 50(4): 239-248, 1pl.
• Baba, K., Hamatani, I. & Hisai, K. (1956) Observations on the spawning habits of some of the Japanese Opisthobranchia. 2. Publications of the Seto Marine Biological Laboratory 5(2): 209-220. (Pls.24-26) [as D. striatus]

Authorship details
Rudman, W.B., 2003 (January 14) Dermatobranchus otome Baba, 1992. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

Dermatobranchus otome from Japan.

January 20, 2003
From: Jun Imamoto

Dear Bill,
Here is another sea slug, Dermatobranchus otome, which I observed in 2002 and i would like to include on the Forum. These sea slugs are found under stones or in the hollow of rocks. I hope these reports are useful for your research.

Upper right: Manazuru, Sagami Bay, Japan, 4 Nov 2002. Size approx: 6mm. Depth: Intertidal. Temperature: 20C. Photo: Jun Imamoto. Lower left: Manazuru, Sagami Bay, Japan, 8 Dec 2002. Size approx: 10mm. Depth: Intertidal. Temperature: 16C. Photo: Jun Imamoto Lower right: Futou Suruga-bay, Japan, 15 June 2002. Size approx: 20mm. Depth: 5m. Temperature: 19C. Photo: Kahoru Imamoto

Best Regards,
Jun Imamoto

Imamoto, J., 2003 (Jan 20) Dermatobranchus otome from Japan.. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Jun,
Thanks very much for these photos. It is very useful to see the colour variation in some of these species. It is interesting to see the black transverse band developing as the animal gets larger, and how the distinctive pinkish ocelli around the black spots on juveniles becomes much less noticeable in larger specimens.
Best wishes,
Bill Rudman

Rudman, W.B., 2003 (Jan 20). Comment on Dermatobranchus otome from Japan. by Jun Imamoto. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from