New radiolaria of the family Prunobrachidae from the uppermost Cretaceous of the eastern Polar Urals

New radiolarian genera and species from Upper Cretaceous siliceous clays of borehole 22 (Polar Urals) are described. The family Prunobrachidae Pessagno, 1975 is reviewed. The new genus Pseudobrachium gen. nov. has a dumbbell skeleton without a patagium and Spinibrachium gen. nov. has apophysis-like spines and a patagium in the central part of the skeleton. Five new species, Spinibrachium amoni, Prunobrachium kozlovae, P. boreale, Pseudobrachium gracile, and P. trilobatum, are described; they are of great importance for paleogeography and stratigraphic correlation of Campanian deposits.