1. Department of Vertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Blvd, Los Angeles, CA 90007, U.S.A.,
2. Department of Vertebrate Paleontology, American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, U.S.A.
3. Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
4. Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560 U.S.A.,
5. North Dakota Geological Survey, Bismarck, ND 58505 U.S.A., ,
6. School of Dentistry, University of California, Los Angeles, 10833 Le Conte Ave., Los Angeles, CA 90095, U.S.A.,