1. Centre for Vertebrate Evolutionary Biology, Institute of Palaeontology Yunnan University Kunming 650091 China
2. Department of Biology Indiana University of Pennsylvania Indiana PA 15705 USA
3. Independent Researcher Kunming 650091 China
4. Key Laboratory of Evolutionary Systematics of Vertebrates Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences Beijing 100044 China