贵州湄潭志留纪初期三叶虫动物群及其意义  

TRILOBITE FAUNA FROM THE LOWERMOST SILURIAN OF MEITAN,GUIZHOU AND ITS IMPLICATIONS

作　　者：魏鑫 詹仁斌[1,3] WEI Kin;ZHAN Ren-bin(State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China;University of Science and Technology of China, Heifei 230026, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]现代古生物学和地层学国家重点实验室中国科学院南京地质古生物研究所,南京210008 [2]中国科学技术大学,合肥230026 [3]中国科学院大学,北京100049

出　　处：《古生物学报》2018年第1期25-39,共15页Acta Palaeontologica Sinica

基　　金：国家自然科学基金(41521061;41290260);中国科学院B类先导专项培育项目(XDPB05);现代古生物学和地层学国家重点实验室基金联合资助;IGCP 653项目(Onset of the Great Ordovician Biodiversification Event)的阶段成果

摘　　要：志留纪兰多维列世(Llandovery)鲁丹期(Rhuddanian)是奥陶纪末生物大灭绝后的残存期和复苏期。志留纪初期冈瓦纳大陆边缘壳相地层稀少,多数地区为沉积间断或笔石相地层,研究底栖壳相生物残存-复苏期的宏演化普遍缺乏理想材料,而华南上扬子区贵州湄潭地区发育了志留纪早期的壳相地层,即五里坡层(鲁丹阶中部)和牛场组(鲁丹阶上部),为探索这一关键地史时期三叶虫动物群宏演化型式及其背景机制提供了依据。贵州湄潭岩坪剖面和高江剖面的五里坡层和牛场组共发现三叶虫7目11科15属(含亚属)17种(含1新种、3未定种),根据其属级分类单元的时空分布规律,将这些三叶虫识别为5种宏演化类型:即减缩幸存型、扩增幸存型、复活幸存型、新生型和死支漫步型。不同类型的属级分类单元在大灭绝中具有不同的宏演化型式,体现出其应对灾变而采取的不同的生存策略。减缩幸存型和复活幸存型是大灭绝后生态系统复苏和再次辐射的主要源泉,它们的发展在一定程度上影响着整个生态系统的宏演化进程;新生型的出现则标志着大灭绝后环境的实质性改善,三叶虫的全面复苏也随之到来。The Rhuddanian（Llandovery, Silurian）includes the survival and recovery intervals respectively after the end-Ordovician mass extinction.The marine environment during the earliest Silurian was dominated by deeper-water,commonly anoxic conditions and sustained transgression,so shelly facies of this time interval are rarely known in the Gondwana and periGondwana regions. However, in the upper Yangtze region of South China paleoplate,some shelly facies are well-developed（e.g.the Wulipo Bed and the Niuchang Formation）.The trilobite fauna documented in this paper provides a unique window for investigating trilobite macroevolution in South China during the Late Ordovician and early Silurian.Trilobite fossils were collected from the Wulipo Bed（middle Rhuddanian）and the Niuchang Formation（upper Rhuddanian） at Yanping and Gaojiang sections of Huangjiaba town, Meitan County, northern Guizhou,including 17 species of 15 genera（subgenera）,11 families and 7 orders, amongst which five macroevolutionary types could be recognized,i.e.the declining survivors,the increasing survivors,the Lazarus survivors,the new arrivals and the Dead Clade Walking（DCW）.Different types of trilobites have different kinds of survival strategies facing the crisis.Declining survivors and Lazarus survivors are major source of biological evolution after the mass extinction,to a certain extent,they influence the process of the biological evolution of the entire ecosystem. New arrivals mark the improvement of the environment after the mass extinction and the beginning of the trilobite recovery interval.

关 键 词：三叶虫动物群 宏演化 五里坡层 牛场组 志留系兰多维列统鲁丹阶 贵州湄潭 

分 类 号：Q915[天文地球—古生物学与地层学]