Bulletin ofZoological Nomenclature 60(3) September2003 233 OPINION 2051 (Case 3179) Halacariis Gosse, 1855, H. ctenopns Gosse, 1855 and Thalassarachna Packard, 1871 (Arachnida, Acari): usage of the names conserved by the designation of a neotype for H. ctenopns Abstract. The Commission has designated a neotype for the marine mite Halacarus ctenopns Gosse, 1855 in the taxonomic sense ofLohmann (1893) in order to conserve usage ofthe names Halacarus, H. ctenopnsand Thalassarachna. The interpretation of the genus Halacarus and of H. ctenopus has been based on Lohmann (1893). The taxon described by Gosse is now placed in Thalassarachiui Packard, 1871 under the name T. ftcw/tr/ (Johnston, 1836). Keywords. Nomenclature; taxonomy; Acari; halacaridae; Halacarus; Thalass- arachna; Halacarus ctenopus; Thalassarachna hasteri; marine mites. Ruling (1) Under the plenary power all previous type fixations for Halacarus ctenopus USNM Gosse, 1855 are hereby set aside and the specimen labelled No. 44—211-27 is designated as the neotype. (2) The following names are hereby placed on the Official List ofGeneric Names in Zoology: (a) Halacarus Gosse, 1855 (gender: masculine), type species by subsequent designation by Viets (1927) Halacarus ctenopus; (b) Thalassarachna Packard, 1871 (gender: feminine), type species by original designation Thalassarachna verrillii Packard, 1871 (a junior subjective synonym ofAcariis basteri Johnston, 1836). (3) The following names are hereby placed on the Official List ofSpecific Names in Zoology: (a) ctenopus Gosse, 1855, as published in the binomen Halacarus ctenopus and as defined by the neotype designated in (1) above; (b) basteri Johnston, 1836, as published in the binomen Acarus basteri (senior subjective synonym of the specific name of Thalassarachna verrillii Packard, 1871, the type species of Thalassaraclma Packard, 1871). History of Case 3179 An application to conserve the usage ofthe generic names Halacarus Gosse, 1855 and Thalassarachna Packard, 1871 and the specific name of Halacarus ctenopus Gosse, 1855 (Arachnida, Acari) by the designation of a neotype for H. ctenopus wasreceivedfrom Use Bartsch (ForschungsinstitutSenckenberg, do DESY, Hamburg, Germany) on 12 October 2000. After correspondence the case was published in BZN 58: 202-205 (September 2001). The title, abstract and keywords of the case were published on the Commission's website. No comments on this case were received. 234 Bulletin ofZoological Nomenclature 60(3) September 2003 Decision of the Commission On 1 March 2003 the members of the Commission were invited to vote on the proposal pubhshed in BZN 58: 203-204. At the close ofthe voting period on 1 June 2003 the votes were as follows: 22 Commissioners voted FOR the proposals. 2 Commissioners (Stys and van Tol) voted AGAINST, no vote was received from Bohme. Voting against, Stys commented that "the author should preferably have applied Article 70.3.2 to endorse Lohmann's (1893) type fixation concomitantly with the establishment ofa new species (ifnecessary) for the misidentified H. ctenopiis sensu Lohmann (1893) non Gosse, 1855. This would have minimalized taxonomic and nomenclatural changes'. Original references The following are the original references to the names placed on Official Lists by the ruling given in the present Opinion: basteri, Acarus, Johnston, 1836, Magazine ofNaturalHistory, 9(63): 353. ctenopus, Halacarus, Gosse, 1855, Annals andMagazine ofNaturalHistory, (2)16: 28. Halacarus Gosse, 1855, Annals andMagazine ofNatural History, (2)16: 28. Thalassarachna Packard. 1871. American Journal ofScience, 3: 108. The following is the reference for the designation ofHalacarusctenopus Gosse. 1855 as the type species ofHalacarus Gosse. 1^55: Viets, K. 1927. Zeitschriftfiir wissenschaftliche Zoologie, 130: 87.