January 29, 2001
From: Rie Nakano
I found this tiny little opisthobranch at Zamami Island, Okinawa, Japan,
December 2000. Depth: 11m Length:5mm
It was found in dead coral.
Dr.Bob Bolland says ;
"The nearest to anything I've seen here is Tambja amakusana. Possibly it's a juvenile Tambja morosa. Quite likely it's an undescribed species".
firstname.lastname@example.orgNakano, R., 2001 (Jan 29) Tambja amakusana from Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3545
From my reading of Baba's description of the colour of his Tambja amakusana, your animal matches it quite well:
"Green colour of body above and below uniformly yellowish green (= grass green) without any trace of spots. The rhinophoral clavi yellow and the branchial rachides yellowish green. There are deep blue (= indigo blue) markings visible on the tips of the rhinophores, branchial plumes and tail"
In your photo however, the whole of the rhinophore club is dark blue, rather than the tip. Unfortunately the species was described from a single specimen so we cannot say how much colour variation is likely to occur in this species. Photos of animals matching Baba's description can be found in Suzuki Keiu's book on Izu Peninsula, Atsushi Ono's book on Kerama Island and Bob Bolland's website.
Perhaps we should call it Tambja cf. amakusana at present.
Baba, K. 1987. Two new green coloured species of Tambja from Japan (Nudibranchia: Polyceridae). Venus, Japanese Journal of Malacology, 46(1): 13-18.