1. Department of Evolutionary Anthropology, Duke University, Durham 27708, NC, USA
2. Department of Mammalogy, Division of Vertebrate Zoology, American Museum of Natural History, Central Park West and 79th Street, New York 10024, NY, USA
3. School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
4. Department of Biology, University of Western Ontario, London N6A 5B7, CA, Canada