Zoological Studies

Vol. 41 No. 4, 2002

Geographical Variation of Mandible Size and Shape in the Wild Pig (Sus scrofa) from Taiwan and Japan

Hideki Endo1,2,*, Yoshihiro Hayashi3, Kyomi Yamazaki4, Masaharu Motokawa5, Jai-Chyi Kurtis Pei6, Liang-Kong Lin7, Cheng-Han Chou7 and Tatsuo Oshida8

1Department of Zoology, National Science Museum, Tokyo, Shinjuku-ku, Tokyo 169-0073, Japan
2Department of Zoology, Faculty of Science, Kyoto University, Kyoto 606-8501, Japan
3Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
4Iwaki Junior College, Iwaki-shi, Fukushima 970-8567, Japan
5The University Museum, Kyoto University, Kyoto 606-8501, Japan
6Department of Wildlife Conservation, National Pingtung University of Science and Technology, Pingtung, Taiwan 91207
7Laboratory of Wildlife Ecology, Department of Biology, Tunghai University, Taichung, Taiwan 407
8Laboratory of Molecular Ecology, Department of Biology, Tunghai University, Taichung, Taiwan 407

Hideki Endo, Yoshihiro Hayashi, Kyomi Yamazaki, Masaharu Motokawa, Jai-Chyi Kurtis Pei, Liang-Kong Lin, Cheng-Han Chou and Tatsuo Oshida (2002) We examined osteometrical characters in the mandibles of the wild pigs (Sus scrofa) from Taiwan, and compared them with those from the Japanese mainland and Iriomote Island (Okinawa Prefecture). Mandibles from Iriomote Island were smaller in size than those from the other localities. Specimens from the Taiwanese population significantly differed from the Mie or Tanba (Honshu) samples in some important measurements such as length of the mandible, although the Mie samples were similar to the Taiwanese ones in many measurements especially in males, while the principal component charts showed that the Taiwanese population is separated from the Oita and Miyazaki (Kyushu) populations for older age classes. Therefore, we concluded that the morphology of the wild pig from Taiwan relatively resembles that of the Japanese wild pig from the Honshu area (Mie and Hyogo (Tanba) Prefectures). The osteological characters in the mandibles of the Taiwanese population have been affected and determined by the following 3 geographical and climatic fac north latitude, 2) being from about 2000 m in elevation, and 3) tors in the habitat: 1) being from having experienced the isolation effect on an 22  to 25 island of 36 000 km2. We suggest that these factors make the mandibles from Taiwan similar to those from the Japanese mainland such as those from Mie.

Key words: Wild pig, Mandible, Osteometry, Taiwan.

*Correspondence: Fax: 81-3-3364-7104. E-mail: endo@kahaku.go.jp