著者

高橋 啓一 小林 巌雄

出版者

地学団体研究会

雑誌

地球科學 (ISSN:03666611)

巻号頁・発行日

vol.40, no.1, pp.39-46b, 1986-01-25

被引用文献数

2

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Three elephant molars from the Pleistocene were found in Niigata Prefecture and reported by MATSUMOTO et al. (1968) have been re-examined. These molars were identified by MATSUMOTO et al. (1968) as Loxodonta (Palaeoloxodori) yabei, L. (P.*) tokunagai junior (=Palaeoloxodon naumanni), but morphological and stratigraphical studies have identified these molars as being from an archtipal mammoth. Specifically, this morphological study identified the Monzen specimen as Mammuthus protomammonteus. In comparison with the measurement of molars of the genus Mammuthus in Europe by MAGLIO (1973), the Monzen specimen is similar to M. armeniacus. This shows that the progression of stages in the development of genus Mammuthus is similar to Europian counterpart. Meanwhile a geological survey has revealed that the Mitama specimen occured in a SK030 bed (1.30 m. y. B. P.), which is the key bed of the most upper part of the middle Formation in the Uonuma Group. Therefore the importance of this specimen to discussion is that the meridionalis type shifted into the armeniacus type in Japan.