1. The University Museum, The University of Tokyo, Tokyo 113-0033, Japan
2. Department of Vertebrate Zoology, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi 11307, Vietnam
3. Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
4. Department of Anatomy and Cell Biology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
5. Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
6. Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi 11414, Vietnam
7. The Kyoto University Museum, Kyoto University, Kyoto 606-8501, Japan