1. Institut für Geowissenschaften und Meteorologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany;
2. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, 210008 Nanjing, PR China;
3. Systematics and Evolution Laboratory, Department of Biology, Western Kentucky University, 42101 Bowling Green, KY, USA