<国立科博専報>山梨県東部産出の中期中新世板鰓類化石

概要

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In the natural history survey conducted in 1980-1981,at the Mt. Fuji National Park, fossil shark teeth of the Middle Miocene were collected from two localities in the eastern part of Yamanashi Prefecture. One of the localities is Mizunoki, Nishi-Katsura machi, Minami-Tsuru gun, and yielded following forms : Isurus hastalis (AGASSIZ), Carcharodon sp., Carcharhinus spp., Negaprion sp., Hemipristis serra AGASSIZ, and Squatina sp. All of these forms are slightly different from close relatives of Recent species. Another locality is Tononoirisawa, Kamigurechi, Shiraito machi, Fuji-Yoshida shi, and yielded teeth of Carcharhinus spp. These specimens were found in sandstones of Furuya Member, Nishi-Katsura Formation, which were deposited at the later part of the Middle Miocene. The Recent relatives of these sharks are inhabitants of warm waters, Especially Hemipristis elongatus (KLUNZINGER) occur from off Vietnam to Indian Ocean. Negaprion is also a warm water shark whick was only recently collected at the southern end of Japanese waters (YOSHINO et al., 1981). The nearest area which has the shark fauna including species of Carcharodon, Negaprion, and Hemipristis are found now off Vietnam, about 2000km to the southwest of Japan. The fossil remains described here indicate that the climate in which the deposition took place was much warmer than now, and comparable to the climate off Vietnam or Gulf of Siam.
国立科学博物館の論文
1982-12-01