1. School of Geography & Tourism Qufu Normal University Rizhao 276826 China
2. A.A. Borissiak Palaeontological Institute Russian Academy of Sciences Moscow 117647 Russia
3. Cherepovets State University Cherepovets 162600 Russia
4. Natural History Museum London SW7 5BD UK
5. Institute of Geology & Paleontology Linyi University Linyi 276000 China
6. State Key Laboratory of Palaeobiology & Stratigraphy Nanjing Institute of Geology & Palaeontology Chinese Academy of Sciences Nanjing 210008 China