1. Yunnan Research Centre for Chengjiang Biota, Yunnan University, Kunming 650091, Yunnan Province, China
2. Department of Geology, University of Leicester, Leicester LE1 7RH, UK
3. Geological Collections, University Museum of Natural History, Oxford OX1 3PW, UK
4. Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3PS, UK