Chromodoris decora Colour Group
How to differentiate the species


The Chromodoris decora 'Colour group' of chromodorid species are all translucent or very pale colours with thin white longitudinal lines on the mantle. I have used often used the concept of Colour Groups in my work on chromodorids because it is an easy way to compare similarly coloured species. There is no suggestion that species of a colour group are necessarily closely related, in fact they are often in different genera.

Rather than try and describe the differences I have illustrated most of the species and suggest you go to the relevant pages for more detailed information. How do we know two very similarly coloured species are different? In most cases there are quite significant anatomical differences, especially in radular morphology. This is not much use in the field. With living animals check the colour of the gills and rhinophores - are there coloured bands?, how many? are the gills simple in shape or triangular or quadrangular in cross-section?, etc. See if there is any indication of the type of mantle glands around the mantle edge. Is there a colour border to the mantle and the foot? does it go all around the border or just around one end? Check the colour of the foot and note whether the gills rhythmically flicker or wriggle when the animal is crawling along.

See the Noumea purpurea - Colour Group Page. Another species not covered here is Hypselodoris capensis, but there is a comparison on the Hypselodoris carnea Page. See also Hypselodoris sp. 2.

  • Rudman, W.B. (1984) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: a review of the genera. Zoological Journal of the Linnean Society 81: 115-273.
  • Rudman, W. B. (1986) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Noumea purpurea and Chromodoris decora colour groups. Zoological Journal of the Linnean Society 86(4): 309-353.
  • Gosliner, T.M. & Johnson, R.F. (1999) Phylogeny of Hypselodoris (Nudibranchia: Chromodorididae) with a review of the monophyletic clade of Indo-Pacific species, including descriptions of twelve new species. Zoological Journal of the Linnean Society, 125: 1-114.
Authorship details
Rudman, W.B., 2000 (February 10) Chromodoris decora Colour Group How to differentiate the species. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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  1. Chromodoris decora Colour Group
    From: Bill Rudman, February 11, 2000

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