Devonian Radiolarians of Russia

This study is devoted to the comprehensive description of radiolarians, the discussion of their morphology, problems of classification, and their role in the history of the Earth's biosphere. It contributes to the solution of the fundamental problems of the evolution of the organic world, aiming at the reconstruction of the dynamics of radiolarian diversity in the Devonian and chorology of units composing it; this is required for a better understanding of patterns and evolutionary pathways and revealing the biostratigraphic potential of radiolarians. The history of the study of Devonian radiolarians is described. The results of original and published studies have allowed the improvement of the radiolarian scale of the Devonian System and recognition of 18 Devonian biostratigraphic radiolarian assemblages and subassemblages, 11 of which are new. General patters of existence of Devonian radiolarians in the Russian Platform are considered. The patterns and adaptation pathways of radiolarians to various environments are determined. Special attention is paid to coevolution of Frasnian radiolarians and ammonoids in the Timan-Pechora Basin. Features of life of radiolarians under conditions of hydrosulphuric contamination are analyzed and a model for cyclic changes in ecological conditions in the basins of the Domanik type is developed. Four migration waves of radiolarians in the Famennian basins of Euramerica and the scenario of wave expansion of radiolarians in the Devonian are established. Seven genera are revised, including Bisphaera, Entactinia, Entactinosphaera, Radiobisphaera, Somphoentactinia, Stigmosphaerostylus, and Trilonche; ten new species are described, namely, Archocyrtium amoenus sp. nov., Bientactinosphaera zuraevi sp. nov., Entactinia bella sp. nov., Haplentactinia kuzminae sp. nov., Haplentactinia vilvaensis sp. nov., Palaeodiscaleksus saturniformis sp. nov., Pluristratoentactinia trisphaerata sp. nov., Somphoentactinia multisphaerata sp. nov., Spongentactinia marina sp. nov., and Spongentactinia polaris sp. nov. The study is expected to be of use to a broad range of readers in paleontology, biostratigraphy, paleoecology, paleobiogeography and as a textbook for the university courses. It contains 40 figures, 17 tables, 40 plates. The list of references includes 444 names.