湖南益阳早奥陶世弗洛期的笔石  

FLOIAN(LOWER ORDOVICIAN)GRAPTOLITES FROM THE YIYANG AREA,HUNAN PROVINCE

作　　者：李丽霞[1] 冯洪真[1] 王文卉[1] 

机构地区：[1]南京大学地球科学与工程学院,南京210093

出　　处：《古生物学报》2010年第2期174-195,共22页Acta Palaeontologica Sinica

基　　金：国家自然科学基金资助项目(No.40972009)

摘　　要：本文报道湖南益阳南坝剖面早奥陶世弗洛期笔石16属30种,描述其中具有重要地层意义的笔石10属16种:Acrograptus affinis,A.gracilis,Baltograptus geometricus,B.vacillans,Clonograptus rigidus,Corym-bograptus deflexus,Cymatograptus undulatus,Didymograptellus bifidus,"Didymograptus"demissus,"D."rigo-letto,Expansograptus hol mi,E.constrictus,Pendeograptus fruticosus,P.pendens,Tetragraptus akzharensis,T.approxi matus。南坝剖面弗洛期笔石动物群以均分笔石为主,同时含有少量反称笔石。该地区弗洛期笔石动物群的分异度、丰度均较高,展示了笔石演化辐射早期斜坡相沉积环境下的笔石动物群特征。本文研究为全面理解奥陶纪笔石的演化辐射积累了重要资料。30 species of Floian（Early Ordovician）graptolites are reported from the Nanba section in the Yiyang area,Hunan Province,and 16 of them are described in detail due to their biostratigraphical importance.The described species are listed as fo-llows：Acrograptus affinis,A.gracilis,Balto-graptus geometricus,B.vacillans,Clonograptus rigidus,Corymbograptus deflexus,Cymatograptus undulatus,Didymograptellus bifidus,＂Didymograptus＂ demissus,＂D.＂ rigoletto,Expanso-graptus holmi,E.constrictus,Pendeograptus fruticosus,P.pendens,Tetragraptus akzharensis,T.approximatus.The Floian graptolite fauna in the Nanba section,only with a few anisograptids remaining from the Tremadocian,is dominated by dichograptids.Both diversity and abundance are high for the Floian graptolite fauna,revealing the feature of this fauna in the slope-facies environment during the early evolutionary radiation of graptolites.The present work accumulates data useful for fully comprehending the evolutionary radiation of Ordovician graptolites.

关 键 词：笔石 弗洛期 早奥陶世 湖南益阳 

分 类 号：Q915[天文地球—古生物学与地层学]