NEW LATE RIPHEAN COMPOSITE MICROFOSSILS FROM THE YENISEI RIDGE

Abstract

Remains of complex prokaryotic and eukaryotic organisms are found in the Seryi Klyuch Formation of the Yenisei Ridge. Taxa described here add substantially to our knowledge of Riphean paleobiology. Precambrian rocks are clearly shown to contain anabaenacean and gomontiellacean Cyanobacteria. Representaives of the family Nostocaceae are found in the Upper Riphean for the first time. Eukaryotes are represented by four genera: the green algae Palaeastritm, acritarchs Cymatiosphaeroides, Trachyhystrichosplmera, and Osculosphaera. In total, nine new microfossil species of seven genera are described from the Lakhanda Horizon of the Yenisei Ridge.