Bulletin of geosciences | |
Middle Ordovician harknessellid brachiopods (Dalmanellidina) from the Mediterranean margin of Gondwana | |
Jiménez-Sánchez A1  Gutiérrez-Marco JC1  Villas E1  Colmenar J1  Reyes-Abril J1  | |
关键词: Ordovician; brachiopods; Orthida; Iberian Peninsula; Spain; Gondwana; | |
DOI : | |
来源: Czech Geological Survey | |
【 摘 要 】
ThefamilyHarknessellidaeBancroft,1928(Orthida,Dalmanellidina)wasdesignedtoembraceanassemblageofspeciesreferredpreviouslytoHarknessellaReed,1917,andincludedfivegeneraknownmainlyfromtheMiddleandUpperOrdovicianofEngland.Herein,wesuggestreassigningtothisfamilythegenusCacemiaMitchell,1974,widespreadinthemiddleDarriwilian(upperMiddleOrdovician)oftheIberianandArmoricanmassifs.Sinceitsdesignation,Cacemiawasplacedamongthedalmanellidinheterorthids,inspiteofitsstronglymucronatehingeline,whichistotallyunknownwithinthisMediterraneanfamily.AnewharknessellidhasbeenidentifiedfromtheupperDarriwilianbedsoftheCentralIberianZone(CentralSpain):IsabelellafascicostellataReyes-Abrilnbsp;Villasgen.etsp.nov.ItissimilartoHorderleyellaBancroft,1928foritscoarselyfascicostellateradialornamentationandobtusecardinalangles,althoughitsconvexoplanetoconvexoconcaveprofileallowsdiscriminationfromthetypicallydorsibiconvexHorderleyella.AphylogeneticanalysisofthefamilyplacesbothCacemiaandIsabelellainbasalpositionsoftheirclades,whichfitswiththeirearlystratigraphicrecord.Basedonourstudy,thefamilyHarknessellidaeappearstohaveoriginatedinthehighlatitudeMediterraneanmarginsofGondwanaduringpre-Darriwiliantimes,beforethedetachmentofAvaloniafromGondwana.ThefamilyreacheditshighestdiversificationinAvaloniathroughouttheLateOrdovician,keepingconnectionswiththeMediterraneanandProto-AndeanmarginsofGondwana,aswellaswiththemid-latitudepalaeocontinentsofBalticaandSouthChina.
【 授权许可】
Unknown
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