Opinion 1734 Ichthyosaurus trigonus Owen, 1840 (currently Macropterygius Trigonus; Reptilia, Ichthyopterygia): neotype replaced by rediscovered holotype

2 Pages·1993·0.38 MB·English

by  International Commission on Zoological Nomenclature

184 BulletinofZoologicalNomenclature50(2)June1993
OPINION 1734
Ichthyosaurus trigonus Owen, 1840 (currently Macropterygius
trigonus; Reptilia, Ichthyopterygia): neotype replaced by rediscovered
holotype
Ruling
(1) ItisherebyconfirmedthatLydekker(1889)didnotvalidlydesignateaneotype
oiIchlhyosawustrigonusOwen, 1840.
(2) Thename MacropterygiusvonHuene, 1922(gender: mascuhne), typespecies
bysubsequentdesignationbyvonHuene(1923)IchthyosaurustrigonusOwen, 1840,
isherebyplacedontheOfficial ListofGenericNamesinZoology.
(3) The name trigonus Owen, 1840, as published in the binomen Ichthyosaurus
trigonusandasdefinedbytheholotype(specimenno.ANSP10124intheVertebrate
Paleontologycollection oftheAcademyofNatural Sciences, Philadelphia, U.S.A.,
figured by Spamer, Bogan & Torrens, 1989) (specific name ofthe type species of
Macropterygiusvon Huene, 1922), is herebyplaced on theOfficial List ofSpecific
NamesinZoology.
HistoryofCase2779
An application to replace the putative neotype ofIchthyosaurus trigonusOwen,
1840bytherediscoveredholotypewasreceivedfromDrsEarleE.Spamer(Academy
of Natural Sciences, Philadelphia, Pennsylvania, U.S.A.) and Hugh S. Torrens
(University ofKeek, Keele, Staffordshire, U.K.) on 13 July 1990. Aftercorrespon-
dencethecasewaspublishedin BZN48: 240-242(September 1991). Noticeofthe
casewassenttoappropriatejournals.
Itwasnoted onthevotingpaperthat Lydekker(1889, p. 22)hadproposedthat
three vertebrae (cervical, dorsal and caudal) figured by Phillips (1871) could
convenientlybetakenas'representingthetypes'ofIchthyosaurustrigonus.However,
theprovenanceofthesevertebraewasunknownandtherewasnoevidencethatthey
came from the same individual or even locality (para. 2 ofthe application). The
selectionofsuchasuiteas"thetypes"didnotconstituteavalidneotypedesignation
(cf. para. 3). Althoughthiswasnotreferredtointheapplication, Lydekker(p. 24)
used the expression 'which may be taken as the type" when comparing Phillips"s
figuredcervicalvertebrawithanotherexample,butthecontextsuggeststhathewas
merelyreferringtoitasbeingthe'type"(i.e. thefigured)cervicalspecimenandnot
selectingthisvertebraasthesinglename-bearerforthespecies.
Lydekker"sstatementsdidnotconstituteaneotypedesignationandtheCommiss-
ionwasaskedsimplytoconfirmthisinanamendedversionofProposal(1)onBZN
48:242.Itwasalsoproposed,inaccordwithusualpractice,thatMacropterygiusvon
Huene, 1922beplacedontheOfficialListofGenericNames;vonHuene(1923,p.
465)haddesignatedIchthyosaurustrigonusOwen,1840asthetypespecies(para.5of
theapplication).
DecisionoftlieCommission
On 1 September 1992 the members ofthe Commission were invited to vote on
Proposal(2)onBZN48:242,togetherwithamendedProposal(I)andtheaddition
BulletinofZoologicalNomenclature50(2)June1993 185
notedabove.Atthecloseofthevotingperiodon 1 December1992thevoteswereas
follows: —
Affirmativevotes 28:Bayer,Bock,Bouchet,Cocks,Cogger,Corliss,Dupuis(in
part),Hahn,Halvorsen,Holthuis,Kabata,Kraus,Lehtinen,Macpherson,Mahnert,
MartinsdeSouza,Minelli,Nielsen,Nye,Ride,Savage,Schuster,Starobogatov,Stys,
Thompson,Trjapit—zin,Ueno,Willink
Negativevotes none.
NovotewasreceivedfromHeppell.
Dupuisabstainedfromvotingontheamended Proposal(1)becausetheneotype
conceptwasunknownatthetimeofLydekker(1889)who,inanycase,hadnot(in
termsofthecurrentCode)validlydesignatedaneotypeforMacropterygiustrigonus.
StyscommentedthatinhisviewtherehadbeennoneedforCommissionaction.Ride
commentedthatLydekker'sactionfailedtomeetthequalifyingconditionsofArticle
75 ofthe Code and therefore the holotype was not threatened in any way by his
suggestionthatPhillips's(1871)vertebralspecimensbetreatedas"types'.Itappeared
thatnonomenclaturalinstabilitywascausedbyrediscoveryoftheholotype.
Originalreferences
ThefollowingaretheoriginalreferencestothenamesplacedonOfficialListsbytheruling
giveninthepresentOpinion:
MacropterygiusvonHuene, 1922,Monographien:urGeologieundPalaeonlologie,1:98.
trigonus.Ichthyosaurus,Owen,1840,Reportofthe9thMeetingoftheBritishAssociationforthe
AdvancementofScience. 1839,8: 124.