Revision of the genus <Emphasis Type="Italic">Entactinosphaera</Emphasis> Foreman, 1963 and the new genus <Emphasis Type="Italic">Retientactinosphaera</Emphasis> gen. nov. (Paleozoic radiolaria)

The genus Entactinosphaera Foreman, 1963 is revised; it is shown to combine seven different genera, which are distinguished by morphological characters and belong to three orders of two radiolarian classes: the class Sphaerellaria, order Entactiniata (Bientactinosphaera, Entactinosphaera, Helioentactinia, Radiobisphaera), and class Spumellaria, orders Cancelliata (Retientactinosphaera, Magnisphaera) and Spongiata (Spongentactinia). New radiolarian taxa from the Middle Frasnian-Lower Famennian of the Timan-Pechora Basin and from the Lower Famennian of the Polar Ural Mountains, Russia, are described: Retientactinosphaera gen. nov., R. magnifica sp. nov., and R. clavata sp. nov.