Neogene micro fossils of chlorophyceae prasinophyceae and acritarchs from nigata central japan
Takashi, K.; Matsuoka, K.
Transactions and Proceedings of the Palaeontological Society of Japan New Series 122: 105-121
The microplankton (Chlorophyceae, Prasinophyceae and Acritarchs) from the Neogene sediments in the Niigata district, central, Japan are reported. Taxa from 8 form genera are described and illustrated: Tytthodiscus densiporosus sp. nov., T. d. densiporosus ssp. nov., T. d. minus ssp. nov. Palambages sp., Pterospermella pterina sp. nov., Leiosphaeridia cf. fastigatirugosa (Staplin) Downie et Sarjeant, L. grandiformis sp. nov., L. minuscula sp. nov., Lancettopsis sp., Micrhystridium ariakense Takahashi, Baltisphaeridium sphaeroides sp. nov., B. nakajoense sp. nov. and Cymatiosphaera pulchella sp. nov. Morphological characteristics of the genera Tytthodiscus, Crassophaera, Pleurozonaria, Tasmanites and Leiosphaeridia are discussed. According to Parke et al. (1978), the fossil genus Pterospermella is a synonym of the recent genus Pterosperma, but acceptance of the genus Pterospermella is suggested. These phytomicroplankton described are important for a basic knowledge of their stratigraphic and geographic distribution in the Neogene formations around the Sea of Japan.