Intraspecific variation and taphonomic alteration in the Cambrian (Furongian) agnostoid Lotagnostus americanus: new information from China

Bulletin of geosciences

Zhu XJ¹  Ahlberg P¹  Dai T¹  Peng SC¹  Terfelt F¹  Babcock LE¹ 

关键词: Cambrian;    Furongian;    agnostoid;    Lotagnostus americanus;    China;    Quebec;   

DOI  :  

来源: Czech Geological Survey

【 摘 要 】

TheconceptoftheagnostoidarthropodspeciesLotagnostusamericanus(Billings,1860),whichhasbeenreportedfromnumerouslocalitiesintheupperFurongianSeries(Cambrian)ofLaurentia,Gondwana,Baltica,Avalonia,andSiberia,isreviewedwithemphasisonmorphologicandtaphonomicinformationaffordedbylargecollectionsfromHunaninSouthChina,XinjianginNorthwestChina,andZhejianginSoutheastChina.ComparisonsaremadewithtypeandtopotypematerialfromQuebec,Canada,aswellasmaterialfromelsewhereinCanada,theUSA,theUnitedKingdom,Sweden,Russia,andKazakhstan.ThenewinformationclarifiesthelimitsofmorphologicvariabilityinL.americanusowingtoontogeneticchangesandvariationwithinholaspides,includinginferredmicroevolution.Italsoprovidesdetailsonapparentvariationoftaphonomicorigin.TheChinesecollectionsdemonstrateamoderatelywidevariationinL.americanus,indicatingthatargumentsfavoringrestrictionofLotagnostusspeciestonarrowlydefined,geographicallyrestrictedformsareunwarranted.SpeciesdescribedasL.trisectus(Salter,1864),L.asiaticusTroedsson,1937,andL.punctatusLu,1964,forexample,fallwithintherangeofvariationobservedinL.americanus,andareregardedasjuniorsynonyms.TheeffacedformLotagnostusobscurusPalmer,1955isremovedfromsynonymywithL.americanus.AreviewofthestratigraphicdistributionofL.americanusasconstruedhereshowsthattheearliestoccurrencesofthespeciesinallregionsoftheworldarenearlysynchronous.

【 授权许可】

Unknown