1. Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, PR China
2. Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
3. Natural History Museum, Cromwell Road, London, SW7 5BD, UK
4. Earth and Environmental Sciences, Graduate Center, City University of New York, NY, 10016, USA