Euryale Lamarck, 1816

Stöhr, Sabine, 2011, New records and new species of Ophiuroidea (Echinodermata) from Lifou, Loyalty Islands, New Caledonia, Zootaxa 3089, pp. 1-50 : 15-16

Genus Euryale Lamarck, 1816

Material. Euryale aspera Lamarck, 1816 . Stn. 1433: 1 spm, stn. 1429: 1 spm, stn. 1461: 1 spm.

Remarks. The nomenclatural status of this genus is currently unclear. According to the principle of priority, the ophiuroid Euryale Lamarck, 1816 is a junior homonym of a medusa Euryale Péron & Lesueur, 1810 . Since Euryale Lamarck, 1816 is the type genus of Euryalidae and also the order Euryalida depends on the validity of the name, it is highly desirable to establish its precedence over the older homonym. In accordance with article 23.9.1. of the International Code of Zoological Nomenclature, prevailing usage of a name must be maintained when a) 'the senior homonym has not been used as a valid name after 1899' and b) 'the junior homonym has been used for a particular taxon, as its presumed valid name in at least 25 works, published by at least 10 authors in the immediately preceding 50 years and encompassing a span of not less than 10 years'. This appears to be the case with Euryale , which has been (and still is) widely used for almost two centuries for an ophiuroid genus by a large number of publications from different fields, 25 of which (published 1966–2007) are listed in the appendix to fulfill the requirements of articles 23.9.1.2. and 23.9.2. To my knowledge, the name Euryale has not been used for a medusa after 1899.

Lamarck (1816) synonymized the cnidariantype species E. antarctica Péron & Lesueur, 1810 with Ephyra , while using Euryale for ophiuroids. This latter decision was not accepted by Fleming (1828), who proposed Astrophyton instead. Astrophyton is currently regarded as a gorgonocephalid genus and indeed, Euryale , Astrophyton and Gorgonocephalus were synonyms as originally published and used ( Verrill 1899a), but split up and delimited from each other by Lyman (1882). Thus, since the requirements of article 23.9.1. are fulfilled, from hereon, the junior homonym is valid, protected (nomen protectum) and has precedence over the older name, which from hereon should be referred to as a nomen oblitum (see article 23.9.2.).

Fell (1960) argued that Euryale should be attributed to Oken, 1815 instead of Lamarck, 1816 on the grounds of priority, probably unaware that Oken (1815) had been rejected for nomenclatural purposes by the international commission in opinion 417 (International Commission on Zoological Nomenclature 1956). Subsequently, several genera and species from that work have been ruled valid in the interest of preventing confusion and establishing nomenclatural stability, but no such ruling exists for Euryale . Consequently, Lamarck (1816) must be considered as authority of the name. Since Oken like his peers used Euryale as a synonym of Gorgonocephalus , no stability on the understanding of the generic concept can be achieved by a ruling in favour of his authority on the name. Furthermore, Oken (1915) used Euryale also for a medusa, which makes the name under his authority ambiguous. Lyman (1882), attributed Euryale to Lamarck, 1816, thus providing an unambiguous concept of the name that was in common use until Fell's (1960) decision to attribute it to Oken.

Cnidara and Ophiuroidea are widely separated taxa, and cnidarian workers may not easily become aware of this nomenclatural act that changes the precedence of the names. To avoid the risk that Euryale Péron & Lesueur, 1810 may be revived in the future, causing confusion again, a proposal to the commission will be prepared to formally suppress the older homonym. This act to establish precedence of the younger name is the required first step.