On the Resident “Bottlenose Dolphins” from Mikura Water. By Tsuneo Kakuda 1) , Yuko Tajima 2) , Kazumi Arai 3) , Kazunobu Kogi 4) , Toru Hishii 5) and Tadasu K. Yamada 6)＊ 角田恒雄 1) ・田島木綿子 2) ・新井上巳 3) ・小木万布 4) ・菱井 徹 5) ・山田 格 6)＊ ：御蔵島 周辺海域に定住する「ハンドウイルカ」について Introduction Systematics is a product of various contemporary competing ideas. Ramping vs. splitting, morphology vs. molecular, and cladistic vs. conventional are some of the representatives of the opposing pairs. Here we discuss systematic position of the dolphin from one geographic area, based on both morphology and molecular phylogeny. “Bottlenose dolphins” inhabit in the water around Mikura Jima (Mikura Island) are seen almost throughout the year. Mikura Jima is a small island in the Pacific Ocean, located about 200 km to the south south-east from Tokyo, where Kuroshio current often crosses Izu Shoto (Izu Islands) (Fig. 1). During the seasons when climate is milder and sea is calmer, dolphin watch and dolphin swim are popular among the visitors. These dolphins have been known as “bottlenose dolphins”, with ventral spots in adults (Shirakihara et al., 2002; Kasuya et al., 1997). They are somewhat smaller than the offshore bottlenose dolphins, and with proportionately long and slender beak (Kasuya et al., 1997) which looks upturned. Tip of the beak is often white in older individuals. Bottlenose dolphins of similar appearances are also known from the seas around Amakusa Shoto, Amami Gunto, and Mem. Natn. Sci. Mus., Tokyo, (38), December 25, 2002 1) Faculty of Science, Kanagawa University 神奈川大学理学部 2) Graduate School of Agricultural and Life Sciences, The Univeristy of Tokyo 東京大学大学院農学生命科学研究科 3) Graduate School of Tokyo Medical and Dental University 東京医科歯科大学大学院医歯学総合研究科 4) Graduate School, Faculty of Bioresources, Mie University 三重大学大学院大学院生物資源学研究科 5) Mikura Jima Iruka Kyoukai 御蔵島イルカ協会 6) Department of Zoology, National Science Museum, Tokyo 国立科学博物館動物研究部 ＊ Corresponding author: 3-23-1, Hyakunin-cho, Shinjuku-ku, Tokyo, 169-0073 Japan e-mail: yamada@kahaku.go.jp 連絡先： 169-0073 東京都新宿区百人町 3-23-1