Re: Aegiridae or Aegiretidae?

July 13, 2005
From: S. Fahey & T. Gosliner

Dear Bill,
Thanks very much for posting the recent messages regarding Aegires. Concerning the family name [#14216 ] .
As you correctly point out, Fischer (1880-1887) was the first to use the sub-family name Aegirinae. And although Iredale and O'Donoghue (1923) used the name Aegiretidae to unite Aegires, Notodoris and Triopella, it was Risbec (1928) who first provided a diagnosis for this group and he called it Aegiridés.
To correctly formulate the Latinized version of Aegirinae at a family level, Iredale and O'Donoghue should have used the ending ...idae on Aegir, the Norse god's name. But, instead they added ...inae, (perhaps to maintain the clade as a subfamily?). Risbec was closer to the correct method when he added ...idés to Aegir. We maintained the name Aegiridae in our publication according to the rules of Latin nomenclature for the taxonomy of biological sciences (rules for animal taxonomy). In no case were we able to find where the extra letters ( should be included with ...idae to form a Latin family name. The suffix ...inae is used for sub-family level in animal taxonomy.
Although Article 29.5 of the ICZN allows the maintenance of current spellings, the article also requires at least 25 citations during the previous 50 years to show that the usage is indeed "current". This is a difficult task to be sure. But it is the requirement in order to determine prevailing usage. We see no reason to continue the incorrect spelling of the family Aegiridae.

Terry and Shireen

Fahey, S. & Gosliner, T., 2005 (Jul 13) Re: Aegiridae or Aegiretidae?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Shireen & Terry,
I suspect we will need to get a ruling from the Commission on this. My problem is that we had a stable usage - Aegiretidae - which has now been rendered unstable. My reading of the Rules is that they are urging us to maintain current usage despite the fact that it is not the original spelling and despite the fact that its derivation from the name of the type genus may not be in accordance with the grammatical procedures. They are clearly saying that keeping usage stable is more important.  

I am sure 25 usages can be found. It just seems a waste of time which could be spent looking at slugs. Unfortunately now that Pandora's box has been opened there is no guarantee that if we go with Aegiridae someone in 5 years won't say we should be using Aegiretidae.

Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Jul 13). Comment on Re: Aegiridae or Aegiretidae? by S. Fahey & T. Gosliner. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from



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