Chromodoris? from western Japan

October 30, 1999
From: Yasuhiro Shirai

Dear Bill.

My name is Yasuhiro Shirai. I am an amateur diver in Japan. This is my first appearance in this site, but I am not good at English.

I've recently found an opisthobranch, but I don't know its name. Please could you help me. I found it at Kushimoto, which is a very famous diving spot in West Japan. It was 3mm long and found at 15m depth (water temperature 25C), in Oct 1999.

Sorry for my poor English.

Best regards,
Yasuhiro Shirai

Shirai, Y., 1999 (Oct 30) Chromodoris? from western Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Yasuhiro,
Welcome to the Forum. Don't worry about your English - it is a lot better than my Japanese!

I'm afraid I can't give you a name for your first photo. At 3mm long it is quite a small animal, but from its shape and colour I don't think it is a juvenile. I would guess that it is a chromodorid belonging to one of the genera like Pectenodoris in which the species grow to less than 10mm in length. It looks quite like Pectenodoris trilineata. Other similarly coloured species are Thorunna florens and Durvilledoris similaris.

I am afraid with these small chromodorids we need to look at their anatomy before we can be sure of the genus they belong to. If you have any other interesting finds I would be happy to see them.

Best wishes,
Bill Rudman.

Rudman, W.B., 1999 (Oct 30). Comment on Chromodoris? from western Japan by Yasuhiro Shirai. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from