Tropical Indo-West Pacific.
UPPER: Wonga Beach, N. of Mossman, Queensland, Australia, January 1974. AM C94083. Photo: I. Loch.
LOWER LEFT: Broadhurst Reef, 12-15m, Townsville, Queensland, 18 Nov 1974, AM C96580. Photo: I. Loch.
LOWER RIGHT: SEM Photo of radula of Wonga Beach specimen. Photo: G. Avern.
This species seems to be quite variable in colour, in particular, the head, rhinophores and oral tentacles appear to range in colour from a translucent orange to a dark translucent blue-black. The second point of variation concerns the areas with opaque white pigementation. In some animals the translucent body wall has scattered patches of opaque white while in other specimens there is a solid colouring of white.
Hamatani's description was based on an animal from Okinawa in which the head was orange and the white pigmentation consisted of scattered, irregular shaped and sized white patches. He described it as having a ground colour which was translucent or colourless or light orange-yellow. The head, oral tentacles and rhinophores were orange red, and over the dorsal and lateral surfaces of the body behind the rhinophores there were many [irregular] opaque white patches. There was a prominent white [median] band on the head beween the rhinophores which extended anteriorly to the lower halves of the oral tentacles and laterally to the outer sides of the rhinophores. The tips of the oral tentacles and rhinophores were white. The upper portion of the cerata were tinged with reddish orange and there was a small white ring below the protruded tip of each ceras. The lower portion of the ceras was covered with clusters of opaque white dots. It was found feeding on the hydroid Aglaophenia cupressina.
The two animals illustrated here represent two extremes of the colour pattern. Other photos in messages from Erwin Koehler and Bernard Picton show other colour variations. The radular morphology illustrated here is identical to Hamatani's dscription.
Note: This species was previously named Cuthona sp. 1 on the Forum.
• Hamatani, I (1993) A new cuthonid species (Nudibranchia, Aeolidacea), Cuthona yamasui n.sp., from Okinawa, Southwestern Japan. Venus, The Japanese Journal of Malacology, 52(2): 127-133. (Figs 1-3)
Rudman, W.B., 2002 (March 13) Cuthona yamasui Hamatani, 1993. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/cuthyama
Trinchesia yamasui from Gulf of Kachchh
From: Vinod Gajjar, April 12, 2010
Cuthona yamasui aggregation
From: Brian Mayes, August 19, 2009
Cuthona yamasui? from Indonesia
From: Linda Ianniello, August 29, 2008
Colour form of Cuthona yamasui
From: Mirjam Broos, February 12, 2008
Cuthona yamasui from the Philippines
From: Colin Teo, July 7, 2007
Cuthona yamasui from Queensland
From: Paul Osmond, March 21, 2007
Cuthona yamasui from the Andaman Sea, Thailand
From: Vie Panyarachun, March 5, 2007
Cuthona yamasui? from Nth Sulawesi
From: Roberto Sozzani, April 10, 2006
Cuthona yamasui from Oman
From: Laurence Gautier, February 8, 2006
Cuthona yamasui from Tioman Island
From: Asther M. Lau, March 9, 2004
Cuthona yamasui mating
From: Erwin Koehler, September 23, 2003
Cuthona yamasui from Indonesia
From: Linda Ianniello, August 26, 2003
Cuthona yamasui from Borneo
From: Makoto Uesugi, July 11, 2003
Cuthona yamasui? - colour variation
From: Nishina Masayoshi, January 2, 2003
Cuthona yamasui from Sumbawa Is, Indonesia
From: Walabha Sinbul, August 9, 2002
Cuthona yamasui from Myanmar
From: Boo Nilsson, May 28, 2002
Cuthona? from the Marshall Islands
From: Scott Johnson, April 12, 2002
Cuthona kanga? from Tanzania
From: Bernard Picton , March 15, 2002
Cuthona yamasui from Queensland
From: Bill Rudman, March 15, 2002
Re: Cuthona sp
From: Erwin Koehler, January 4, 1999
Cuthona kanga? from Philippines
From: Erwin Koehler, December 23, 1998