[PapersinPalaeontology,2014,pp.1–32]

CONODONTSINTHEUPPERORDOVICIANKEISLEY

LIMESTONEOFNORTHERNENGLAND:TAXONOMY,

BIOSTRATIGRAPHICALSIGNIFICANCEAND

BIOGEOGRAPHICALRELATIONSHIPS

€12

bySTIGM.BERGSTROMandANNALISAFERRETTI

1DivisionofEarthHistory,SchoolofEarthSciences,TheOhioStateUniversity,125S.OvalMall,Columbus,OH43210,USA;e-mail:Bergstrom.1@

2DipartimentodiScienzeChimicheeGeologiche,l.goS.Eufemia19,41121Modena,Italy;e-mail:ferretti@unimore.it

Typescriptreceived9February2014;acceptedinrevisedform15July2014

Abstract:TheclassicalfaunafromtheKeisleyLimestone,ellaandNotiodellaarediscussed.ItisproposedthatBirksfeldia

oneofthe?rstUpperOrdovicianconodontfaunasdescribedisaseniorsynonymofGamachignathusandNotiodellaa

fromtheUK,isre-evaluatedbasedonrelativelyabundantcol-juniorsynonymofIcriodella.ThedescribedKeisleyspecies

lectionsofwell-preservedconodontelementsrepresentingassociation,whichrepresentstheA.ordovicicusZoneandisof

20multielementtaxa.CommontaxaarerepresentativesoflateKatian(Ka4)age,iscloselysimilartothoseoftheBoda

Amorphognathusduftonus,Birksfeldiacircumplicata,Eocarnio-Limestoneofsouth-centralSwedenandsomeotherEuropean

dusaff.E.gracilis,Hamarodusbrevirameus,Scabbardellaalti-faunas,butcoevalshallow-waterfaunasfromeasternNorth

pes,Strachanognathusparvusandseveralconiformspecies.AmericadifferinseveralrespectsfromtheseEuropeanfaunas.

Theseoccurwithmorerarespecimensof,amongothers,Biostratigraphyandcarbonisotopechemostratigraphyindi-

Aphelognathusnudus,Amorphognathus