Aegiridae or Aegiretidae?

July 11, 2005
From: Bill Rudman

In Fahey & Gosliner's recent paper on Aegires (2004) I was puzzled to see that they spell the family name Aegiridae. To my knowledge, the only use of the spelling Aegiridae in the primary literature has been by Willan (Marshall & Willan, 1999; Willan, 2000). Fahey & Gosliner outline the history of the usage of the family-group names Notodorididae and Aegiretidae, (including Aegirinae, Aegiridae) and state:

In the most recently published classification of Aegiretidae, Rudman (1998) placed Aegires and Notodoris in the Family Aegiretidae .........  the incorrect spelling of the family name [being] continued. The correct spelling, Aegiridae is discussed in detail by Willan(2000).”

I disagree with this on two grounds. Most previous authors, and I, don't consider the spelling is incorrect, and I don't think Willan discussed this matter in any detail at all. In Fahey & Gosliner's discussion, two issues concerning the family-group name are discussed together, and it is probably better to separate them first.

Issue 1. Fischer (1883) divided the family Polyceridae into three sub-families, Acanthodoridinae, Polycerinae and Aegirinae.  Bergh (1892:141) considered Aegires, Notodoris and Triopella to be a group of related genera within the Polyceridae but did not formally name the group.  Iredale and O’Donoghue (1923) introduced the family name Aegiretidae for Aegires, Notodoris and Triopella. We cannot be sure, but considering the energy Iredale spent in researching old names, it is probable that they were aware that the family group Aegiretidae (Aegirinae) was an older name than Notodorididae, Eliot, 1910. The only dispute in the literature has been whether the Family name should be Aegiretidae or Notodorididae. Apart from Eliot and Odhner, most authors have considered Aegiretidae to have clear priority.

Issue 2. Aegiretidae or Aegiridae?

Willan (2000) wrote:
"Another incorrect family name is Aegiretidae (e.g., Rudman 1998). Aegiretidae is wrong on two grounds. It is not a Latin or Greek word, but was named after Aegires, a Norse God, so only Article 29.3.3 of the Code applies in this case. The earliest spelling was “Aegirinae” (Fischer 1883: 523) ........ hence Aegiridae must be maintained as the correct name for the family. And secondly, most authors use Aegiridae today in both the scientific and popular literature, so according to Article 29.5 of the Code, that spelling has to be maintained."

This is the 'in detail' discussion referred to by Fahey & Gosliner. Willan's statement is only correct in parts. It is true that the name is based on that of a Norse God, but it was spelled Aegir, or something similar - Aegires was Fischer's Latinisation of it. This may be important, because in the formation of family-group names, the International Rules require you to identify the 'stem' of Latin and Greek names and add the appropriate ending. With names from other languages, the ending still needs to be identified in the construction of the Family name. What Iredale & O'Donoghue obviously did was take Fischer's subfamily name Aegirinae and apply the rules, as they understood them, to arrive at Aegiretidae. They do not discuss this in their publication, but unfortunately Iredale seldom clarified his nomenclatural decisions by confiding in his readers.

I strongly dispute Willan's claim that "most authors use Aegiridae today" and in the list below only one author - Willan (in Marshall & Willan,1999) uses that spelling, all the rest use Aegiretidae. Willan cites Article 29.5 to justify his usage, but Article 29.5 in fact counters his argument about the possible incorrect formation of the name, because the Article specifically preserves names which have been incorrectly formed. I quote the relevant clause so that there is no room for misinterpretation

Article 29. 5 Maintenance of current spellings. If a spelling of a family group name was not formed in accordance with Article 29.3 but is in prevailing usage, that spelling is to be maintained, whether or not it is the original spelling or whether or not its derivation from the name of the type genus is in accordance with the grammatical procedures in Article 29.2.1 and 29.3.2 [ICZN 4th edition 1999]

I have not searched for every use of Aegiridae and Aegiretidae but I have looked at all the authors cited by Fahey & Gosliner and others who have in recent years described or examined species of Aegires. I have not included authors who have used Notodorididae (or Notodoridae). I would consider the only conclusion a reasonable person could reach is that the name in current usage is Aegiretidae. Under Article 29.5 we do not need to consider Fischer's original spelling, or the possibility that Iredale & O'Donoghue may have misconstructed the name. I have no feeling of 'ownership' for Aegiretidae, I just feel it is important that we maintain current usage wherever possible.

Authors using Aegirinae:

  • Fischer, P. 1880–1887. Manual de Conchyliologie et de Paleontologie Conchyliologique. Librairie F. Savy, Paris. xxiv + 1369 pp.

Authors using Aegiretidae

  • Baba, K. (1974). New distributional record of Aegires punctilucens (d'Orbigny, 1837) from Sado Island, Japan. (Nudibranchia: Doridoidea : Aegiretidae). The Veliger 17(1):11–12.
  • Bertsch, H. (1980) The nudibranch Aegires albopunctatus (Polyceratacea: Aegiretidae) preys on Leucilla nuttingi (Porifera: Calcarea). The Veliger 22: 222-224.
  • Edmunds, M. (1971). Opisthobranchiate Mollusca from Tanzania (Suborder: Doridacea). Zoological Journal of the Linnean Society 50(4):339–396.
  • Fischer, E., Franc, A., Martoja, M,  Termier, M, & Termier, H. 1968. Mollusques gastéropodes et scaphopodes. Libraires de L'Académie de Médecine, Paris. 1084 pp.
  • Iredale, T. & O'Donoghue, C.H. (1923) List of British nudibranchiate Mollusca. Proceedings of the Malacological Society of London 15:115–226.
  • Nordsieck, F. (1972). Die euriopäischen Meeresschnecken (Opisthobranchia mit Pyramidellidae, rissoacea), vom Eismeerbis Kapverden, Mittlemeer und Schwarzes Meer. Fischer Verlag, Stuttgart. 327 pp.
  • Ortea, J. A., Luque, A. A., & Templado, J. (1990) Contributions to the knowledge of the genus Aegires Lovén, 1844 (Opisthobranchia: Doridoidea: Aegiretidae) in the north Atlantic, with descriptions of two new species. Journal of Molluscan Studies 56: 333-337.
  • Pruvot-Fol, A. 1930. Diagnoses provisoires (incomplètes) des espèces nouvelles et liste provisoire des mollusques nudibranches recueillis par Mme Pruvot-Fol en Nouvelle-Calédonie (Ile des Pins). Bulletin du Muséum National D'Histoire Naturelle 2:460.
  • Pruvot-Fol, A. (1954). Mollusques Opisthobranches. Faune de France, Office Central de Faunistique, Paris. 460 pp.
  • Rudman, W.B. (1998). Suborder Doridina. Pages 990–1001 in P.L. Beesley, G.J.B. Ross, and A. Wells, eds., Mollusca: The Southern Synthesis. Fauna of Australia. 5, Part B. CSIRO Publishing, Melbourne.  
  • Schmekel, L., &  Portmann, A. (1982). Opisthobranchia des Mittelmeeres. Nudibranchia und Saccoglossa. Springer-Verlag, Berlin. 410 pp.
  • Templado, J., Luque, A. A., & Ortea, J. (1987) A new species of Aegires Loven, 1844 (Opisthobranchia; Doridacea; Aegiretidae) from the Caribbean Sea: Aegires ortizi spec. nov., with comparative descriptions of the North Atlantic species of this genus. The Veliger 29: 303-307.

Usng Aegiridae

  • Fahey, S. J. & Gosliner, T. M. (2004) A Phylogenetic Analysis of the Aegiridae Fischer, 1883 (Mollusca, Nudibranchia, Phanerobranchia) with Descriptions of Eight New Species and a Reassessment of Phanerobranch Relationships. Proceedings of the California Academy of Sciences, 55, (34): 613–689, 82 figs., 4 tables (Appendix).
  • Marshall, J.G., & Willan, R.C. (1999). Nudibranchs of Heron Island, Great Barrier Reef. Backhuys, Leiden. 257 pp.
  • Willan, R. C. (2000). Family names, particularly Polyceridae and Aegiridae. Nudibranch News 3(3):1–3.

Best wishes
Bill Rudman

Rudman, W.B., 2005 (Jul 11) Aegiridae or Aegiretidae?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from



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