The 'Exmouth Chromodoris'

September 29, 2000
From: Drew Taylor


These three Nudibranchs I photographed at Bundegi Reef in Exmouth [Northwestern Australia] in November 1999. The reef was damaged severly after Cyclone Vance but it is great to see that the Nudibranchs manage to live on. I have identified them as being in the Family Chromodorididae with the common name being "Exmouth Chromodoris" (Nudibranchs of the South Pacific). Can you please confirm this for me?

During this dive my buddy and I observed these Nudibranchs to be mating and the third one in the picture had its reproductive pore exposed and was attempting to get in on the fun.

P.S. I love your site, and I will be spending hours on it.

Drew Taylor

Taylor, D., 2000 (Sep 29) The 'Exmouth Chromodoris'. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Drew,
This is one of a group of animals which I am calling at present Hypselodoris bullocki. This colour form is quite common in northwestern Australia from Darwin around to Exmouth. If you look at the other messages about Hypselodoris bullocki you will see plenty of photos showing the various colour variations. I have included a close-up photo of the mating pair.

Neville Coleman has indeed called this the 'Exmouth Chromodoris' but I personally don't like authors making up 'common' names for animals. Firstly they are not names in 'common use' and often different authors will make up their own 'common names' which is very confusing for interested amateurs. A perfect example is found with fish. The fishing industry and fish scientists have spent many years and much effort in trying to prepare a standard list of common names to be used in Australia. Often the same common name has ben used in different parts of Australia for different fish. Ironically if they had just used the scientific names there would have been no confusion and everyone on the world would know what they mean. I think most amateur naturalists are quite capable of using scientific names. After all gardeners do it all the time when discussing plants. This is a rather long-winded way of saying that 'Exmouth Chromodoris' is a bit unfortunate because the species is a Hypselodoris not a member of the genus Chromodoris. If you are going to use a scientific genus name as part of the common name why not just use the scientific name?

Thanks for the beautiful photo, and another record of this colour form.

Best wishes,
Bill Rudman.

Rudman, W.B., 2000 (Sep 29). Comment on The 'Exmouth Chromodoris' by Drew Taylor. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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