Biostratigraphic significance of new fossil species of the diatom ganera Stephanodiscus and Cyclotella from Upper Cenozoic deposits of Lake Baikal, Siberia

摘要

Three new extinct taxa of the genus Stephanodiscus Ehrenberg (S. Williamsii sp. nov., S. Princeps sp. nov., S. Yukonensis var. Antiquus var. nov) andfour new extinct species and two new extinct varieties of the genus Cyclotella (Kutzing) Brebisson (C. iris var. insueta var. nov., C. tempereiformica sp. nov., C. distincta sp. nov., C. comtaeformica sp. nov., C. comtaeformica var. spinata var. nov. and C. praeminuta sp. nov.) are described from Upper Cenozoic lacustrine sediments of Lake Baikal (boreholes BDP-96-1 nd BDP-96-2).