Siraius immonda from sthn Queensland

May 21, 2007
From: Gary Cobb

Concerning message #2276:

Hope the holiday was good...when are messages going to able to be sent again? I would like to send to you a nice one...Siraius 14 mm long found at 16m depth under overhang off Mooloolaba. Thanks Bill!


Cobb, G., 2007 (May 21) Siraius immonda from sthn Queensland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Gary,
My holiday seems a long time ago now. Since returning I have had to spend time on finishing a scientific, edit some other people's papers, go through the backlog of emails etc that built up while I was away and start to go through the unanswered messages to the Forum which have been building up since Christmas. I have decided to keep on with answering those for a couple more weeks before opening the floodgates for more messages. If anyone has an urgent, or particularly exciting message, or wishes to reply to an existing message you can still post messages through the reply button on every page.

Now to your Siraius message. Thanks for these nice photos. Angel Valdes (2002) in his survey of the cryptobranch dorids decided to synonymise about 10 genera  including Siraius and Doriorbis which have been used for this species, into the old genus Doris. This study has certainly given us food for thought but I think it is too early to accept all the synonymies without further consideration. One methodological practice I have difficulty with is the use only of type species of genera. If you just compare one species of each genus then 2 or 3 small anatomical differences may seem insignificant, but if there are 5 or 10 species all with the same differences then surely the fact that there are groups of species with the same small differences becomes significant in itself - and in a cladogram would add a further level of branching? That after all is what genera are supposed to be - groups of species with the same differences. If you only use type species then you are deliberately avoiding the possibility of groups.

  • Valdés, A. (2002) A phylogenetic analysis and systematic revision of the cryptobranch dorids (Mollusca, Nudibranchia, Anthobranchia). Zoological Journal of the Linnean Society 136: 535-636.

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (May 21). Comment on Siraius immonda from sthn Queensland by Gary Cobb. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Siraius immonda

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