The representative radiolarian assemblage different in taxonomy from all kn
own coeval assemblages of Sakhalin was discovered in the basal beds of the
Lower Krasnoyarka Subformation of the upper Campanian in the Susuya River b
asin of southwestern Sakhalin. It appeared to be hardly correlative with co
eval assemblages from adjacent and remote areas. The article presents descr
iptions of the new genus Bipylovnella gen. nov, and new species Bipylomella
sachalinica sp. nov., Hexaloche (?) horridus sp. nov., and Spongostaurus (
) sachalinensis sp. nov.