Japan (Echizen Coast; Yamaguchi Prefecture; Hachijo Is)
Baba notes that the animal has elongate anterior foot corners and 'exceeding elongate' cerata. The colour is distinctive with orange red spots scattered on the head, back, sides and lower half of the cerata. The oral tentacles and upper half of the rhinophores are orange yellow. The upper half of the cerata is dusted with opaque white and the cerata are tipped with yellow. 5-7mm long.
• Baba, K. (1975) On two new species of Eubranchus from Ayukawa, Echizen coast, Japan Sea side of Middle Japan (Nudibranchia: Eolidoidea: Eubranchidae). Venus, The Japanese Journal of Malacology, 34(3-4): 65-72.
Rudman, W.B., 2002 (July 9) Eubranchus echizenicus Baba, 1975. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/eubrechi
August 8, 2008
From: David Mullins
Our recent shift from Brisbane to Woody Point on the Redcliffe Peninsula has resulted in my almost daily haunting of the gutters and reefs at low tide in our front yard.
Locality: Woody Point, Redcliffe Peninsula, Moreton Bay, intertidal, Queensland, Australia., Pacific Ocean, 08 July 2008, Intertidal weed, rocky substrate. Length: 3 mm to 6 mm. Photographer: David Mullins.
I thought that you and the readers of the Forum might find this particular species of Tergipedidae which we believe is a Cuthona/Trinchesia sp. to be of interest. I have to date been unable to find a match for this animal. They were chanced upon as a "colony" of approx. 6 specimens, ranging in size from 3 mm to 6 mm, grazing on hydroids growing on the thallus of "seaweed" attached to the rocky substrate.
I am intrigued by the manner in which they bear their cerata as being certainly quite distinctive if not perhaps characteristic. Additional photos showing a close up of the ceras shows the nematocysts acquired and accumulated from their hydroid prey, a ventral view of the head region, and a specimen upon the hydroids on which they were feeding.
Mullins, D.A., 2008 (Aug 8) Eubranchus echizenicus ? from sthn Queensland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21763
Thanks for this interesting record. I puzzled for a while over its identity, as I didn't think it was a cuthonid. The twisted cerata reminded me of some species of Phyllodesmium but your report of of it feeding on hydroids didn't fit, and neither did the rounded corners of the anterior foot.
I am pretty sure this is a species of Eubranchus, and most probably Eubranchus echizenicus, which up until now has only been reported from Japan. It has similarly twisted cerata, large spots, as in your animals, and rounded anterior foot corners. One other interesting feature is the accumulation of white spots at the tip of each ceras which you identified as the nematocysts. Nematocysts, when present, are stored in an internal sac [cnidosac] which opens terminally. These white spots are acid glands in the skin. They are present in some cuthonids but more importantly are particularly well-developed in many eubranchids, and when present often completely obscure the internal cnidosac as is the case in your animals.
July 11, 2002
From: Nishina Masayoshi
I feel the animal Shouichi Kato's message is Eubranchus echizenicus (Baba, 1975). My friend T. Kenji found a similar animal at Omijima, Yamaguchi Prefecture and it was identified as E. echizenicus. Please take a look, http://www.h.do-up.com/home/takayan/takaPage430.htm.
Both look the same to me.
email@example.comMasayoshi, N., 2002 (Jul 11) Eubranchus echizenicus from Hachijo Islands, Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7511
I agree they look the same. I have had another look at Baba's original description of Eubranchus echizenicus and agree that it is most probably this species. Mr Kenji's photo, showing a side view, shows the white on the cerata and the orange-red restricted to the upper half of the rhinophores very clearly. Thanks very much for drawing my attention to this identification. It is a perfect example of how valuable our collaboration on the Forum is. The only easily available published information on this species is the original description, which included a black & white line drawing of the animal. To see photos of living animals makes it so much easier to compare it with similarly coloured, and spotted. species from Japan ans elsewhere.
April 9, 2002
From: Shouichi Kato
Please see an attached, an animals which may be a kind of Cuthona or Eubranchus. It was a sole species, found on the wall overhung at a depth of 12m and measured 5mm in length. I couldn't find any picture of similar animal in some books I have. Would appreciate your advice.
firstname.lastname@example.orgKato, S., 2002 (Apr 9) Eubranchus? sp. from Hachijo Islands, Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6409
I'm afraid I have can't help identify this beautiful animal. The shape of the cerata are quite suggestive of Phyllodesmium, but that is only a guess.