Triassic radiolarians of Kotel’nyi Island (New Siberian Islands, Arctic)

Triassic radiolarians from Kotel’nyi Island (New Siberian Islands, Arctic Region) are studied. Radiolarians occur in the Middle and Upper Triassic beds, which are well dated by ammonoids, nautiloids, and bivalves. In the Middle Triassic beds, which are composed of dark gray and black clays and claystones with interbeds of combustible schist, siltstone, clayey limestone, and many phosphatic concretions, the following two assemblages are recognized: (1) a Late Anisian assemblage, including Glomeropyle clavatum Bragin, sp. nov., G. boreale Bragin, G. manihepuaensis Aita, G. insulanum Bragin, sp. nov., Triassospongosphaera multispinosa (Kozur et Mostler), Tetraspongodiscus hibernus Bragin, sp. nov., T. borealis Bragin, sp. nov., Eptingium abditum Bragin, sp. nov., E. manfredi Dumitrica, Spongostephanidium japonicum (Nakaseko et Nishimura), and Ladinocampe vicentinensis Kozur et Mostler; (2) Late Ladinian assemblage, with Muelleritortis firma (Gorican), M. kotelnyensis Bragin, sp. nov., Tiborella nivea Bragin, sp. nov., Pseudostylosphaera goestlingensis (Kozur et Mostler), P. omolonica Bragin, Triassospongosphaera multispinosa (Kozur et Mostler), Sarla cincinnata Bragin, sp. nov., S. obscura Bragin, sp. nov., S. prava Bragin, sp. nov., and Eonapora stiriaca Bragin, sp. nov. The Upper Triassic beds, composed of gray and black clays and claystones with lenses of clayey limestones, with sideritic and phosphatic-calciferous concretions have yielded (1) an Early Carnian assemblage, with Pentactinocarpus colum Bragin, sp. nov., Glomeropyle cuneum Bragin, sp. nov., G. algidum Bragin, sp. nov., G. aculeatum Bragin, sp. nov., Kahlerosphaera isopleura Bragin, sp. nov., Stauracanthocircus folium Bragin, sp. nov., Tetraspongodiscus uncatus Bragin, sp. nov., Poulpus costatus (Kozur et Mostler), Eonapora robusta Kozur et Mostler, Planispinocyrtis kotelnyensis Bragin, sp. nov., Annulotriassocampe baldii (Kozur), and Pseudoeucyrtis annosus Bragin, sp. nov.; (2) a Middle-Late Carnian assemblage with Pseudostylosphaera glabella Bragin, sp. nov., P. gracilis Kozur et Mock, P. voluta Bragin, sp. nov., P. gelida Bragin, sp. nov., Kahlerosphaera unca Bragin, sp. nov., K. aspinosa Kozur et Mock, K. fuscinula Bragin, sp. nov., K. acris Bragin, sp. nov., Capnuchosphaera kuzmichevi Bragin, sp. nov., C. triassica De Wever, C. angusta Bragin, sp. nov., Sarla intorta Bragin, sp. nov., S. compressa Bragin, sp. nov., S. aequipeda Bragin, sp. nov., Betraccium irregulare Bragin, B. kotelnyensis Bragin, sp. nov., Spongotortilispinus carnicus Kozur et Mostler, S. subtilis Bragin, sp. nov., Dumitricasphaera simplex Tekin, D. aberrata Bragin, sp. nov., D. arbustiva Bragin, sp. nov., Zhamojdasphaera epipeda Bragin, sp. nov., Z. proceruspinosa Kozur et Mostler, Vinassaspongus subsphaericus Kozur et Mostler, Palaeosaturnalis triassicus Kozur et Mostler, Paronaella concreta Bragin, sp. nov., P. aquilonia Bragin, sp. nov., Tetraspongodiscus cincinnalis Bragin, sp. nov., Annulotriassocampe baldii (Kozur), Canoptum zetangense Wang et Yang, Whalenella speciosa (Blome), Syringocapsa turgida Blome, Droltus gelidus Bragin, sp. nov., and D. niveus Bragin, sp. nov.; (3) an Early Norian assemblage with Pseudostylosphaera glabella Bragin, sp. nov., P. gelida Bragin, sp. nov., P. voluta Bragin, sp. nov., Kahlerosphaera retunsa Bragin, sp. nov., Capnuchosphaera deweveri Kozur et Mostler, Sarla globosa Bragin, sp. nov., Palaeosaturnalis mocki Kozur et Mostler, Paronaella aquilonia Bragin, sp. nov., Syringocapsa turgida Blome, and Droltus gelidus Bragin, sp. nov.; (4) a Middle Norian assemblage with Sarla globosa Bragin, sp. nov., Sarla sp., Syringocapsa turgida Blome, Canoptum sp., and Laxtorum? sp. The fact that these assemblages include taxa that are recorded more southerly, including paleotropical localities, and support dating based on mollusks, enables the use of these data for Boreal-Tethyan correlation. The greatest similarity to Tethyan associations is observed in the Late Carnian and Early Norian, that is, the periods of the greatest penetration of thermophilic mollusks into this basin. A total of 69 radiolarian species of 3 orders, 18 families, and 29 genera are described; 44 species are newly described; the stratigraphic and geographical ranges of the majority of taxa are improved considerably.