Ceratosoma sinuatum
(van Hasselt, 1824)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae

DISTRIBUTION

Indo-West Pacific

PHOTO

Upper: Solitary Islands, northern New South Wales, Australia, April 1987. Photo: Bill Rudman. Lower: Florida Group, Solomon Islands, November, 1999. Photo: M.J. Adams.

Note added 4 July 2007: The name is changed today from C. sinuata to C. sinuatum - see message #20101.

Until now I have, like Baba & Hamatani (1974), considered all the various coloured forms of 'Miamira' to be part of one variable species, Ceratosoma sinuatum  [see message #19853] but after reviewing the available names [message #19854] I am also recognising C. flavicostatum and a group of animals which may well be Ceratosoma magnificum.

In C. sinuatum the background colour ranges from bright green to dull purplish brown and the whole body is covered with low rounded yellow tubercles. Both the gills and the rhinophores are translucent greenish or brownish - depending on the background colour - and have scattered white spots. The anterior end of the mantle is trilobed with the central lobe being much longer than the other two.

From the available information it would seem there are at least two species in this group, one with rounded tubercles and white spots on the gills and rhinophores, which is C. sinuatum, and one with a ridged pattern and distinctive white lines on the gills which can be identified as Baba's  Ceratosoma flavicostatum. As mentioned above, C. magnificum may be a thrid species. [Earlier names for C. sinuatum include Doris sinuata van Hasselt, 1824 and Miamira nobilis Bergh, 1875].

• Baba, K. (1940)  Miamira flavicostata n.sp., a nudibranchiate mollusc from Amakusa, Japan. Zoological Magazine, Japan 52(6), 239-240.
• Baba, K & Hamatani, I. (1974) On the synonymy of Miamira sinuata (van Hasselt, 1824) from Japan (Nudibranchia: Dorididae: Miamirinae). Venus, The Japanese Journal of Malacology 33 (2, August), 81-84.
• Eliot, C.N.E. (1910) Nudibranchs collected by Mr. Stanley Gardiner from the Indian Ocean in H.M.S. Sealark. Reports of the Percy Salden Trust Expedition to the Indian Ocean in 1905, under the leadership of Mr. J. Stanley Gardiner, M.A. Transactions of the Linnean Society, Zoology, series 2, 13(2), 411-439, Pl. 25.
• Valdes, A. & Gosliner, T. (1999) Reassessment of the systematic status of Miamira Bergh, 1875 and Orodoris Bergh, 1875 (Nudibranchia; Chromodorididae) in light of phylogenetic analysis. Journal of Molluscan Studies, 65:33-45.

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