32 Bulletin ofZoological Nomenclature 62(1) March 2005 OPINION 2092 (Case 3223) Unio ochraceus Say, 1817 (currently Ligumia ochmcea; Mollusca, Bivalvia): specific name given precedence over that of Mytilus fluviatilis Gmelin, 1791 Abstract. The Commission has ruled that the specific name of the American freshwater mussel Unio ochraceus Say, 1817 is given precedence over that ofMytilus fluviatilis Gmelin, 1791 whenever the two are considered to be synonyms. Keywords. Nomenclature; taxonomy; Mollusca; unionidae; Ligumia ochracea; Mytilusfluviatilis; tidewater mucket; fresh water mussel; clam; America. Ruling (1) Under the plenary power it is ruled that the name ochraceus Say, 1817, as published in the binomen Unio ochraceus, is hereby given precedence over the namefluviatilis Gmelin, 1791, as published in the binomen Mytilusfluviatilis, whenever the two are considered to be synonyms. (2) The following names are hereby placed on the Official List ofSpecific Names in Zoology: (a) ochraceus Say, 1817,'as published in the binomen Unio ochraceus, with the endorsement that it is to be given precedence over the name fluviatilis Gmelin, 1791, as published in the binomen Mytilusfluviatilis, wheneverthe two are considered to be synonyms; (h)fluviatilisGmelin, 1791, aspublishedinthebinomenMytilusfluviatilis, with the endorsement that it is not to be given priority over the name ochraceus Say, 1817, as published in the binomen Unio ochraceus, whenever the two are considered to be synonyms. History of Case 3223 An application to conserve the widdy used specific name of Unio ochraceus Say, 1817 (currently Ligumia ochracea) for the American freshwater mussel (tidewater mucket) (family unionidae) by giving it precedence over the little used senior subjective synonym Mytilusfluviatilis Gmehn, 1791 was received from James R. Cordeiro (ScienceDivision, Nature Serve. Boston, MA. U.S.A.) on 2 November2001. After correspondence the case was published in BZN 60: 20-22 (March 2003). The title, abstract and keywords ofthecasewere published on the Commission's website. No comments on this case were received. Decision ofthe Commission On 1 September 2004 the members ofthe Commission were invited to vote on the proposals published in BZN 60: 21. At the close ofthe voting period on 1 December 2004 the votes were as follows: 22 Commissioners voted FOR the proposals, 2 Commissioners voted AGAINST, Ng was on leave of absence. Voting for, Bouchet commented that the application stated (para. 3) that Simpson (1914), Ortmann(1919), Frierson (1927) and Haas (1969)allused thenamefluviatilis. Bulletin ofZoological Nomenclature 62(1) March 2005. 33 However, examination of the works in question revealed that these authors cited 'Mytilus fluviatilis Dillwyn, 1817' or 'Anodonta fluviatilis' in the synonymy of Anodonta cataracta Say, 1817, and did not usefluviatilis Gmelin, 1791 as the valid name ofa species. Morrison (1974) is in fact the only 20th century author who used the specific namefluviatilis Gmelin, 1791 as the valid name of a species, but this is enough to exclude the case from Article 23.9. The application fails to mention that Morrison (1974) designated a neotype for Mytilusfluviatilis Gmelin, 1791, and did not report whether or not there exists original type material of Unio ochraceus Say, 1817. Ifthere is, itwouldhavebeen relevant to knowwhetherthename-bearingtypes ofthetwonominal speciesareconsidered by theapphcant to besubjective synonyms. Ifthere is not, it could be appropriate to designate the neotype ofMytilusfluviatilis Gmelin, 1791 also the neotype of Unio ochraceus Say, 1817. Original references The following are the original references to the names placed on Official Lists by the ruling given in the present Opinion: fluviatilis, Mytilus, Gmelin, 1791, Caroli a Linne Systema Naturae, vol. 1, part 6 (Vermes), p. 3359. ochraceus, Unio, Say, 1817, Nicholson's Encyclopedia or Dictionary ofArts & Sciences, Ed. 1, vol. 4 (Conchology), pi. 2, fig. 8.