BulletinofZoologicalNomenclature48(1)March 1991 83 OPINION 1633 HaplocanthosaurusHatcher, 1903(Reptilia, Saurischia):conserved Ruling (1) Under the plenary powers the generic name Haplocanthus Hatcher, 1903 is herebysuppressedforthepurposesofthePrincipleofPrioritybutnotforthoseofthe PrincipleofHomonymy. (2) The name Haplocanthosaurus Hatcher, 1903 (gender: masculine), type species, by monotypy of the replaced nominal genus Haplocanthus, Haplocanthus priscus Hatcher, 1903,isherebyplacedontheOfficialListofGenericNamesinZoology. (3) The name priscus Hatcher, 1903, as published in the binomen Haplocanthus priscus (specific name of the type species of Haplocanthosaurus Hatcher, 1903), is herebyplacedontheOfficial ListofSpecificNamesinZoology. (4) The name Haplocanthus Hatcher, 1903, as suppressed in (1) above, is hereby placedontheOfficialIndexofRejectedandInvalidGenericNamesinZoology. HistoryofCase2684 An application for the conservation of Haplocanthosaurus Hatcher, 1903 was received from Drs Spencer G. Lucas & Adrian P. Hunt (New Mexico Museum of Natural History, Albuquerque, U.S.A.) on 8 November 1988 and published in BZN 46: 262-263 (December 1989). Notice ofthe case was sent to appropriatejournals. Nocommentswerereceived. DecisionoftheCommission On 1 September 1990 the members ofthe Commissionwere invited to vote on the proposalspubHshedin BZN46: 262. Atthecloseofthevotingperiodon 1 December 1990thevoteswereas—follows: Affirmative votes 25: Bayer, Bock, Cocks, Cogger, Corliss, Dupuis, Hahn, Heppell, Holthuis, Kraus, Macpherson, Mahnert, Martins de Souza, Minelli, Mroczkowski. Nielsen, Nye, Ride, Savage, Schuster, Starobogatov, Thompson, Trjapitzin, Ueno,—Willink Negativevotes 2: Kabataand Lehtinen. NovotewasreceivedfromHalvorsen. Kabata preferred not to set aside the Principle ofPriority and thought that little inconveniencewouldresultiftheoldernamewereused. Originalreferences ThefollowingaretheoriginalreferencestothenamesplacedonOfficialListsandanOfficial IndexbytherulinggiveninthepresentOpinion: HaplocanthosaurusHatcher, 1903 (June), ProceedingsoftheBiologicalSocietyofWashington, 16: 100. Haplocanthus Hatcher, 1903 (February), ProceedingsoftheBiologicalSocietyofWashington, 16: 1. priscus,Haplocanthus,Hatcher, 1903,ProceedingsoftheBiologicalSocietyofWashington,16: 1.