日本の外帯の下部白亜紀系産 Onychiopsis yokoyamai

概要

論文の詳細を見る
Onychiopsis, a fern genus with uncertain affinity is common in occurrence in the Middle Jurassic-Lower Creaceous plant-beds in Japan and all Onychiopsis leaves known from the Japanese plant-beds had been regarded as O. elongata, the type species of the genus by the previous authors. In this paper, however, we propose Onychiopsis yokoyamai (YABE) based on its leaves of bipinnate habit with sessile fertile organ and reveal that O. yokoyamai is peculiar in occurrence to the Upper Jurassic-Lower Cretaceous plant-beds in the Outer Zone of Japan and is specifically distinct from O. elongata represented by the leaves of tripinnate habit with stalked fertile organ. We also make here the detailed comparison of Onychiopsis yokoyamai with other Onychiopsis species hiterto known based mainly of their forms of leaves and fertile organs. The recognition of Onychiopsis yokoyamai in the Late Jurassic-Early Cretaceous floras in the Outer Zone of Japan strongly supports the senior author (KIMURA)'s idea that the Late Jurassic-Early Creatceous Tetori-type floras in the Inner Zone of Japan are distinct in floristic character from the coeval Ryoseki-type floras in the Outer Zone of Japan.
国立科学博物館の論文
1986-06-22