1. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment Chinese Academy of Science Nanjing 210008 China
2. University of Chinese Academy of Sciences Beijing 100049 China
3. Museum für Naturkunde Leibniz Institute for Evolution and Biodiversity Science Berlin 10115 Germany
4. Institute of Botany Jiangsu Province and Chinese Academy of Sciences Nanjing 210014 China