Discovery of the Middle-Late Triassic elasmobranch ichthyoliths from the Guanling area,Guizhou,SW China
Discovery of the Middle-Late Triassic elasmobranch ichthyoliths from the Guanling area,Guizhou,SW China
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摘要: 应用Johns等(1997)的形态分类系统,对首次报道出现于贵州关岭地区中上三叠统的软骨鱼类的微体化石进行了初步研究,描述了其中的1个牙齿化石(可能属于弓鲛鲨科的)和7个鳞片类化石的形态属种,其中包括两个鳞片类化石的新属种,即Lobaticoronacf.floriditurris,Sacrisubcoronacf.circabasis,Glabrisubcoronacf.arduidevexa,Parvi-coronadacrysulcan.gen.et.n.sp.s.f.,Annulicoronapyramidalisn.gen.et.n.sp.s.f.,new(?)parageneraA和new(?)parageneraB。还初步探讨了软骨鱼类微体化石在三叠纪地层划分中的应用,以及中国西南部三叠纪软骨鱼类与北美相当地层中软骨鱼类的洲际对比。Abstract: Abundant Middle-Late Triassic(Ladinian-Carnian)elasmobranch ichthyoliths(microscopic shark dermal denticles and teeth)from the Zhuganpo and Xiaowa Formations in the Guanling area,Guizhou Province,south-western China,are described and illustrated.The fauna includes a single tooth possibly belonging to Hybodontidae and7paragenera and paraspecies of dermal denticles,i.e.:Lobaticorona cf.floriditurris,Sacrisubcorona cf.circaba-sis,Glabrisubcoro na cf.arduidevexa,Parvicorona dacrysulca n.gen.n.sp.s.f.,Annulicorona pyramidalis n.gen.n.sp.s.f.,and new(?)paragenera A and B.This is the first time that shark dermal denticles are reported from the Metapolygnathus polygnathiformis M.nodosus conodont zones.The application of microfossils of chondrichthyes in the stratigraphic division of the Triassic and the intercontinental correlation of Triassic chondrichthyes in south-western China and those in equivalent strata in North America are also discussed.
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