1. School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, People's Republic of China
2. Functional Morphology and Biomechanics, Zoology Department, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
3. Department of Biology, University of Washington, Seattle, WA 98105, USA
4. Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98105, USA