Evolution and paleogeography of Eospirifer(Spiriferida,Brachiopoda) in Late Ordovician and Silurian  

作　　者：ZHAN RenBin JIN JiSuo LIANG Yan MENG LingKai 

机构地区：[1]State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,China [2]Department of Earth Sciences,University of Western Ontario,London,ON N6A 5B7,Canada

出　　处：《Science China Earth Sciences》2012年第9期1427-1444,共18页中国科学（地球科学英文版）

基　　金：supported by Chinese Academy of Sciences (Grant No. KZCX2-YW-Q05-01);National Natural Science Foundation of China(Grant No. 40825006);the CAS/SAFEA International Partnership Program for Creative Research Teams and the State Key Laboratory of Paleobiology and Stratigraphy

摘　　要：Eospirifer,the oldest known genus of the spiriferide group(Brachiopoda),first appeared on the Zhe-Gan Platform of South China paleoplate during late Katian(Late Ordovician) represented by E.praecursor.It survived the end-Ordovician mass extinction,and reappeared on the Upper Yangtze Platform of South China paleoplate by the end of Ordovician near the upper part of the Normalograptus persculptus Biozone.Starting from the beginning of Silurian,Eospirifer experienced some morphological innovations and expanded its geographical distribution substantially.It reached its species diversity acme and the widest geographic distribution in Wenlock(middle Silurian),with the diversity hotspots in Laurentia,Avalonia,and Baltica.Various shell size frequency curves of E.praecursor under different paleogeographic settings suggest that this pioneer species of Eospirifer,with several macroevolutionary novelties,adopted a range of life strategies to adapt to the changing environments during early spiriferide evolution.There are also some morphological macroevolutionary trends during the evolutionary history of Eospirifer from Late Ordovician to the end of Silurian,such as the ever enlarging shell sizes and the width/length ratios from late Katian to Wenlock,but decreasing apparently of both parameters from Wenlock to Pridoli.Eospirifer,the oldest known genus of the spiriferide group（Brachiopoda）,first appeared on the Zhe-Gan Platform of South China paleoplate during late Katian（Late Ordovician） represented by E.praecursor.It survived the end-Ordovician mass extinction,and reappeared on the Upper Yangtze Platform of South China paleoplate by the end of Ordovician near the upper part of the Normalograptus persculptus Biozone.Starting from the beginning of Silurian,Eospirifer experienced some morphological innovations and expanded its geographical distribution substantially.It reached its species diversity acme and the widest geographic distribution in Wenlock（middle Silurian）,with the diversity hotspots in Laurentia,Avalonia,and Baltica.Various shell size frequency curves of E.praecursor under different paleogeographic settings suggest that this pioneer species of Eospirifer,with several macroevolutionary novelties,adopted a range of life strategies to adapt to the changing environments during early spiriferide evolution.There are also some morphological macroevolutionary trends during the evolutionary history of Eospirifer from Late Ordovician to the end of Silurian,such as the ever enlarging shell sizes and the width/length ratios from late Katian to Wenlock,but decreasing apparently of both parameters from Wenlock to Pridoli.

关 键 词：Eospirifer MACROEVOLUTION Ordovician-Silurian species diversity paleogeographic distribution 

分 类 号：P531[天文地球—古生物学与地层学] Q915.816[天文地球—地质学]