Chromodoris orientalis from Japan

August 29, 2001
From: Nishina Masayoshi

We are able to see Chromodoris orientalis very commonly in Sagami Bay and on the Echizen Coast of Japan. There is very little colour variation.

UPPER PHOTO: Echizen Coast, Japan
Date: 21 July 2001
Depth: 5m

LOWER PHOTO: Shiba saki Hayama, Sagami Bay, Japan.
Date: 4 Aug 2001
Depth: 5m
Length: 30mm

Best Regards,
Nishina Masayoshi

Nishina, M., 2001 (Aug 29) Chromodoris orientalis from Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Nishina,
Thanks for your photos. With Jun Imamoto's photos they suggest that the deep yellow mantle border is a more common colour form than the orange-yellow photographed by Brian Darvell in Hong Kong. The dendritic branching of the mantle glands is also very noticeable.

Another interesting point is the way the inner edge of each gill has a black or dark brown line, replacing the orange or yellow line along the outer edge. This feature was not visible in photos of Hong Kong specimens and I can't find reference to it in earlier Japanese records of the species (as Glossodoris pallescens). While checking this point in the literature I noticed a description of the egg ribbon (Baba et al, 1956). This species is apparently one of a group of species in which the egg ribbon is attached flat on the substrate rather than just along one edge. Have you seen any egg masses of this shape nearby?

• 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.

Thanks very much,
Bill Rudman

Rudman, W.B., 2001 (Aug 29). Comment on Chromodoris orientalis from Japan by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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