1. Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
2. Department of Anatomy, Faculty of Veterinary Medicine, Gadjah Mada University, Yogyakarta 55281, Indonesia
3. Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Science, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido 060-0818, Japan