Name changes in Ceratosoma

July 5, 2007
From: Bill Rudman

In Gary Cobb's recent message [#20098] he uses the spelling Ceratosoma sinuatum for the species which has usually been called Doris sinuata or Miamira sinuata in the scientific literature, and I have been calling Ceratosoma sinuata on the Forum. Gary and Richard Willan used the same spelling [sinuatum ] in their recent book Undersea Jewels - A colour guide to Nudibranchs and also changed the spelling of Ceratosoma magnifica to C. magnificum. Unfortunately they make no comment on these changes in their book and I note on websites a certain amount of confusion is already growing because people don't know if this is a spelling error by them or what?

Their spelling is in fact correct. They are just following the International Code of Zoological Nomenclature which unfortunately puts adherence to the grammar of dead languages ahead of name stability. Under the Rules, the gender of the species part of the name must match the gender of the genus part of the name. This is particularly incomprehensible to English speakers whose language does not have gender-based words. While I accept we need some rules when a name is made for a new species, a real problem  arises when research shows that a species should be moved to another genus. If the new genus name is of a different gender then the ending of the species part of the name needs to change.

In this case Ceratosoma has a Greek derivation and is neuter. This means that, the following species which have all changed genera since being described need a spelling revision:

Ceratosoma amoena should be  Ceratosoma amoenum.
Miamira flavicostata
should be  Ceratosoma flavicostatum
Miamira sinuata should be Ceratosoma sinuatum
Miamira magnifica should be Ceratosoma magnificum
Orodoris miamirana
should be  Ceratosoma miamiranum

Please don't send Richard and Gary any hatemail - they are just following the Rules. As you may have guessed I find this need to change the endings of names when generic placements change quite ridiculous.With our growing dependence on computerised databases, a rule that forces names to change at the whim of the latest phylogenetic hypothesis is not helpful. I have recently discussed why we retain 4 or 5 different spellings of names based on Eduard Rüppell [message #1998] to ensure 'stability' yet here we have a rule which ensures instability by insisting on names changing to match the gender of their 'new' genus whenever a phylogenetic change is made.

Bill Rudman

Rudman, W.B., 2007 (Jul 5) Name changes in Ceratosoma. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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