Ceratosoma flavicostatum
(Baba, 1940)

Suborder: DORIDINA
Family: Chromodorididae


Western Pacific


Upper: Coffs Harbour region, northern New South Wales, November 1990. AM C164521. Lower: Jibbon Head, Port Hacking, Sydney, NSW, Nov. 1981. Photos: Bill Rudman.

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

This species has often been identified as Miamira magnificum Eliot, 1910, but there is considerable confusion surrounding the identity of that species. Until now I have, like Baba & Hamatani (1974), considered all the various coloured forms of 'Miamira' to be part of one variable species of Ceratosoma [see message #19853]. As outlined in a separate message [#19854] I am now recognising Ceratosoma sinuatum and Ceratosoma flavicostatum as separate species, and separating a few western Indian Ocean animals as possible specimens of C. magnificum.

Ceratosoma flavicostatum usually has a broad whitish margin to the mantle and the rest of the mantle is a reddish brown or even purple with orange rounded ridges. The rhinophores usually lack white markings, but the gills are edged with opaque white lines. The front of the mantle does not have a prominent central lobe. In both this species and C. sinuatum there can be up to three large tubercles in the dorsal midline between the gills and the rhinophores. If present, the most posterior one, just in front of the gills, is the longest, often standing much taller than the gills.

C. flavicostatum was first described from Japan and has been reported since from many parts of the tropical western Pacific. The name flavicostatum [= yellow ridges] indicates one of the most obvious characters of this species.

  • 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.

Bill Rudman

Authorship details
Rudman, W.B., 2007 (April 30) Ceratosoma flavicostatum (Baba, 1940). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/ceraflav

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  1. Re: Ceratosoma flavicostatum feeding
    From: Teresa Zuberbühler, June 10, 2008
  2. Coincidental occurrence of Ceratosoma flavicostatum & S. ornatum
    From: David Mullins, September 6, 2007
  3. Re: Ceratosoma flavicostatum feeding
    From: Leanne & David Atkinson, July 5, 2007
  4. Ceratosoma flavicostata feeding
    From: Danny Van Belle, April 30, 2007
  5. Ceratosoma sinuata from Queensland
    From: Gary Cobb, July 14, 2003
  6. Sprinting Ceratosoma sinuata
    From: Sabine Noack, October 22, 2002
  7. Ceratosoma magnifica trailing
    From: Ákos Lumnitzer, January 10, 2002
  8. Ceratosoma sinuata from Indonesia
    From: Ken Knezick , January 16, 2001
  9. Re: Left-handed Ceratosoma sinuata
    From: Donata P. & Akos L., October 27, 2000
  10. Ceratosoma sinuata - magnifica form
    From: Akos L. & Donata P, October 25, 2000
  11. Ceratosoma sinuata - how long-lived?
    From: Donata P. & Akos L., October 19, 2000
  12. Miamira from New South Wales
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