Conodont biostratigraphy and biodiversity of the middle to Upper Ordovician near Shitai of Anhui Province, South China

Darriwilian to early Katian conodonts are documented herein from the Kuniutan, Datianba and Pagoda formations at the Daling section of southern Anhui Province, East China, representing a typical Ordovician succession of the marginal Yangtze Platform. A total of 5228 conodont specimens, assigned to 20 genera and 29 species, were recovered from 56 carbonate samples. Seven conodont biozones are recognized, including (in ascending order) the Lenodus antivariabilis, the L. variabilis, the Yangtzeplacognathus crassus, the Dzikodus tablepointensis, the Y. jianyeensis, the Baltoniodus alobatus and the Hamarodus brevirameus biozones. They provide new data for an improved biostratigraphic correlation of these formations regionally and internationally. Furthermore, the detailed conodont biostratigraphy reveals a hiatus between the top of the Kuniutan Formation and its overlying Datianba Formation at the Daling section, missing the stratigraphic interval spanning from the Eoplacognathus suecicus Biozone (middle Darriwilian) to the lower part of the Pygodus anserinus Biozone (lower Sandbian). Based on the conodont data from the Daling section, the conodont biodiversity shows a prominent increasing trend within the D. tablepointensis Biozone (middle Darriwilian) in the Kuniutan Formation and a moderately increasing trend in the H. brevirameus Biozone (lower Katian) in the Pagoda Formation.Fang-yi Gong* [fygong@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Beijing, China; University of Science and Technology of China, Hefei, China. Rong-chang Wu [rcwu@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Beijing, China. Yong-yi Zhen [yong-yi.zhen@planning.nsw.gov.au], Geological Survey of New South Wales, W.B. Clarke Geoscience Centre, 947–953 Londonderry Road, Londonderry, Australia. Xiao-cong Luan [xcluan@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Beijing, China. Ren-bin Zhan [rbzhan@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Beijing, China. Guan-zhou Yan [gzyan@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of China, Beijing, China.