The First Discovery of Colonial Radiolarians in the Jurassic Sediments (Arctic Zone of Siberia)
New data on the first finding of colonial radiolarian genus <i>Siphonospaera</i> are provided. It was found in the Upper Jurassic (lower Volgian = lower Tithonian) deposits of the Bazhenovo horizon on Yamal Peninsula in Arctic periphery of Western Siberia. The importance of this find for understanding the geological history of the colonial radiolarians is shown. New species <i>Siphonosphaera yamalica</i> Vishnevskaya et Amon, is described.