Cuthona diversicolor
Baba, 1975
Order: NUDIBRANCHIA
Suborder: AEOLIDINA
Family: Tergipedidae
DISTRIBUTION
Known from Hong Kong and Japan.
PHOTO
Hong Kong Workshop, April 1983. AM C139106
UPPER: head and anterior end of an animal with little blue in its colour pattern. Photo: Bernard Picton. LOWER: Head and full photo of another specimen. Photo: Brian Darvell.
Tergipedid with a characteristic colour pattern. The body is translucent colourless with a scaterring of irregularly shapes bright yellow and milky blue patches. The head is translucent orange and the oral tntacles and smooth rhinophores are a very pale translucent orange, which becomes more intense towards the tip. There are a few scattered yellow patches on both rhinophores and oral tentacles. The cerata are translucent clear with small scattered yellow specks. Towards the tip there is a thin orange band, and below it, a broader milky blue band. The blue band is not always present. The digetsive gland is black, giving the cerata a granular black appearance. It grows to 15-20mm in length.
Reference:
• Baba,K (1975) Description of Trinchesia diversicolor spec. nov. from the Japan Sea coast of Middle Japan (Nudibranchia: Eolidoidea (Cuthonidae). The Veliger, 17(3): 251-254.
Rudman, W.B., 2001 (August 9) Cuthona diversicolor Baba, 1975. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/cuthdive
Related messages
Re: Color variation of Cuthona yamasui?
November 6, 2006
From: Francesco Ricciardi
Concerning message #16277:
Dear Bill,
This is a aeolid nudibranch from North Sulawesi, on the stinging hydroid Aglaophenia cupressina.
Locality: Manado, 10, North Sulawesi, Indonesia. Length: 2 cm. Photographer: Francesco Ricciardi.
Is it Cuthona yamasui? It seems to be very very different, but is the only species I found living on this hydroid.
Thanks
Francesco
francesco@biodiving.it
Ricciardi, F., 2006 (Nov 6) Re: Color variation of Cuthona yamasui?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/18197
Dear Francesco,
If you do a search on the Forum for Aglaophenia you will see there are a number of nudibranchs which feed on species of this genus of hydroids. Amongst tropical aeolids have a look at Ching Yao Chan's message [#16249] which describes ann animal which is identical to yours. As he suggests, it certainly could be a colour form of Cuthona diversicolor. It will be interesting when someone has the opportunity to study its anatomy.
Best wishes,
Bill Rudman
Cuthona diversicolor? from Taiwan
April 10, 2006
From: Ching Yao Chan
Dear Bill,
These two photos were shot in Kenting of Taiwan. Are they Cuthona diversicolor Baba, 1975 ? or some other species?
Locality: Kenting, 10 m, Taiwan, Taiwan Sea, 22 April 2005, Coral Reef. Length: 60 mm. Photographer: C.Y.Chan & Kuang.
Best Regards,
C.Y.Chan
logic.chan@msa.hinet.net
Chan,C.Y., 2006 (Apr 10) Cuthona diversicolor? from Taiwan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16249
Dear Ching Yao,
It's quite possible that they are a colour form of C. diversicolor. I note that some Japanese specimens have quite a large opaque white patch on the head and behind the rhinophores like yours does, but in your animal the orange bands on the cerata are not as thin and precise as in other specimens I have seen. I suspect the identity of the hydroid it is on might give us a clue.
Hopefully someone familiar with the species can give us some background information.
Best wishes,
Bill Rudman
Cuthona diversicolor from Sth Korea
July 11, 2002
From: Dong Bum, Koh
Dear Bill,
I`d like to send you a photo of Cuthona diversicolor for the Forum.
Mun islet, CheJu Island, Sth Korea. 15m depthNov. 2001
Photographer: Dong Bum, Koh
Best wishes,
Dong Bum, Koh
drkoh@seasee.co.kr
Koh, D.B., 2002 (Jul 11) Cuthona diversicolor from Sth Korea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7447Thanks Dong Bum,
It's useful to get a photo of it on one of its food hydroids. The bright red-orange rhinophores are interesting. when you look at the other photos on the Forum you can see that the colour varies from translucent clear with white specks, through animals with an orange tip, or an orange basal band, to animals such as yours in which the whole rhinophore is deep orange-red.
Best wishes,
Bill Rudman
Cuthona diversicolor from Hachijo Island, Japan
October 25, 2001
From: Nishina Masayoshi
Dear Dr.Rudman,
This animal is may be Cuthona diversicolor.
Hachijo Island, Japan, 21 Oct, 2001
Length: 8mm
Photo by Nishina Chikako
Best Regards,
Nishina Masayoshi
nishina@wips.co.jp
Nishina, M., 2001 (Oct 25) Cuthona diversicolor from Hachijo Island, Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5557Dear Nishina,
Yes this is Cuthona diversicolor. The orange colour seems much brighter in Japanese specimens than those from Hong Kong.
best wishes,
Bill Rudman
Cuthona diversicolor from Hong Kong
August 17, 2001
From: Bernard Picton
Hi Bill,
Here are pictures of Cuthona diversicolor from Hong Kong. One picture shows the animal in situ, apparently feeding on a hydroid which might be a species
of Aglaophenia. This nudibranch was fairly frequent during the workshop, often hiding beneath algae at the base of the hydroid.
9 Apr 1983 - Mit Kok Tsui, Wong Wan Chau - 3-15m
Bernard
bernard.picton.um@nics.gov.uk
Picton, B.E., 2001 (Aug 17) Cuthona diversicolor from Hong Kong. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/5054Thanks Bernard,
I have added some more information on this species at the top of the page. Sometimes, as in your photo, the blue band on the cerata, below the gold subapical ring, is absent. When I get a chance I will also add further records of this species from Hong Kong.
Cheers,
Bill Rudman
