1. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China.
2. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
3. Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China.
4. College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.