Cuthona cf. pinnifera

Family: Tergipedidae


Hachijo Island, Japan, 6m. Length: 8mm. Photo: Nishina Masayoshi

See my comments below.

Authorship details
Rudman, W.B., 2002 (March 21) Cuthona cf. pinnifera [In] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

Is this Cuthona pinnifera?

March 23, 2002
From: Nishina Masayoshi

Dear Bill,
I saw this Aeolidia at Hachijo Island before but I have no idea what this is. I will be happy if you have some advice.

Date: 3 March, 2002
Location: Hachijo Island Japan
Depth: 6m
Length: 8mm

Best Regards,
Nishina Masayoshi

Masayoshi, N., 2002 (Mar 23) Is this Cuthona pinnifera?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Nishina,
The semicircular ridges on the rhinophores are very unusual. The only species that comes to mind is Cuthona pinnifera which was described from Sagami Bay by Baba as Cratena pinnifera.

Unfortunately I can find very little in the literature about colour variation in this species so I really can't be sure. One thing that would be useful to know is whether the front of the foot is rounded at the corners or whether the anterior corners are developed into pointed tentacles. In Cuthona pinnifera the anterior corners of the foot are rounded.

Terry Gosliner (1964) identified an animal from Hawaii as this species and it certainly fits your photos in most features. At them moment I think it is best to call it Cuthona cf. pinnifera until we know more.

• Abe,T (1964) Opisthobranchia of Toyama Bay and adjacent waters. Hokuryu-kan, Tokyo. 99pp., 36 Plates pages.
• Baba,K (1949) Opisthobranchia of Sagami Bay collected by His Majesty The Emperor of Japan. Iwanami Shoyen, Tokyo. 194pp., 50 Pls pages.
• Gosliner, T.M. (1979) The systematics of the Aeolidiacea (Nudibranchia: Mollusca) of the Hawaiian Islands, with descriptions of two new species. Pacific Science, 33(1): 37-77.

Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Mar 23). Comment on Is this Cuthona pinnifera? by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from