Foraminifers of the Genus Janischewskina Mikhailov from the Upper Viséan-Serpukhovian (Mississippian) of Eurasia

The foraminiferal genus Janischewskina of the family Janischewskinidae Reitlinger, 1996, which is widespread in Eurasia and plays an important role in stratigraphy of the Upper Viséan-Serpukhovian interval of the Lower Carboniferous (=Mississippian), is revised. The morphological characteristics of the genus and species were clarified and supplemented, details of the structure of the interseptal space and sutural apertures are clarified, and the stratigraphic and geographical distribution of the species is documented. A new foraminiferal species J. adtarusia Gibshman, Zaytseva and Stepanova, sp. nov. is described.