Stratigraphic potential of Ataxophragmiida (Foraminifera) for Cretaceous sediments of Western Siberia

Morphological complication of Foraminifera from Ataxophragmiida order there are relatively haight stratigraphic significance for Cretaceous deposits of Western Siberia; from them the genus Gaudryinopsis Podobina, 1975 have spread vertical the most widely. It have known from Jurassic to Eocene including. The last time new species of this genus - G. sibiricus Podobina sp. nov. have been faund. This species have offered as species - index for early Aptian deposits of the Northern palaebiographical region of Western Siberia. The other species - index G. filiformis (Berthelin) is characteristic for middle Albian this region. The boundaries of this species have been defined from Ob River to areas of Yamal Peninsula. In Senomanian stage the marine facies with species - index G. elongatus Podobina also have preserved in such limits of Northern region. The early Turonian species -index G. angustus Podobina widely spread on all territories of Western Siberia. The other species - index of the genus G. vulgaris (Kyprianova) have speed in general in early Santonian deposits. But this species shells have found in small quantaties because could not be the index - species for this part of section. The second genus Pseudoverneuilina Podobina gen. nov. is characteristic for Aptian and Albian deposits of this region. Proposed taxon - doubles differ by chemical wall content and something morphological certains. These general doubles have been offered: Gaudryina Orbigny, 1839 - Gaudryinopsis Podobina, 1975; Verneuilina Orbigny, 1839 - Pseudoverneuilina Podobina gen. nov. and other doubles such genera. The first genera from indicated doubles have origined from calcareus facies and its agglutinat wall content have such material. In opposite the second genera from doubles have kwart - siliceus wall. The spreding of these second genera limited by terrigenius clay-opoka facies. The creation of these facies are defined by Boreal transgression and these genera have known in Northern paleobiogeographical region. In this article the shot description of Pseudoverneuilina Podobina genera are cited. The studied species of two genera - Gaudryinopsis Podobina, 1975 and Pseudoverneuilina Podobina gen. nov. are given on the I-V Paleontological tables. Painter O.M. Lozovaya for figs on I-V Paleontolog. tables. The author declares no conflicts of interests.

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