РАННИЕ ПРЕДСТАВИТЕЛИ МШАНОК РОДА Nikiforovella Nekhoroshev, 1948 И ИХ СТРАТИГРАФИЧЕСКОЕ ЗНАЧЕНИЕ ДЛЯ ПОЗДНЕГО ДЕВОНА-РАННЕГО КАРБОНА

The arm of the present paper is to evaluate the significance of species from genus Nikiforovella for stratigraphy of Devonian-Carboniferous boundary from different regions of Eurasia. The study is based on author and museum collections of the Late Devonian-Early Carboniferous bryozoans from Southern Urals, western part of the Altai-Sayan Folded Area, south-western of the West-Siberian plate, Rhenish massif, and Namur-Dinant Basin. The material was studied using a binocular microscopic. The morphological descriptions for each species were prepared in result of researching oriented sections. The first phylogenetical scheme of the genus Nikiforovella are offered on the base of statistical analyses of species features in Famennian-Tournaisian. Bryozoans from genus Nikiforovella are distributed in Northern hemisphere of the Earth in Carboniferous predominantly. The genus is stratigraphical significant because presented by low amount of taxa with short time interval of development. The specific view of colony surface (formed by a combination of autozooecies and heterozooecies) allows easy identified these bryozoans on first steps of research. Totally conclusions are next: Uppermost Famennian from some regions of Eurasia consists of various bryozoans from genus Nikiforovella. The genus has distinctly morphological particularities; Genus Nikiforovella are characterized changing of morphological particularities and species composition on the lower boundary of the Carboniferous ( sulcata Conodont Zone); During Famennian-Tournaisian phase of evolution Nikiforovella demonstrated tendencies to increase of size, number and changing disposition of metazooecies and acanthostyles; Phylogenetical scheme of this genus may be used for division and correlation of Upper Devonian-Lower Carboniferous deposits in some regions of Eurasia. Species N. gracilis Ernst, Herbig, 2010 and N. cf. gracilis Ernst, Herbig, 2010 are typical for the Uppermost Famennian of Rhenish Massif and Southern Urals respectively. Species N. alternata Nekh., 1956 are spread in Lower Tournaisian of Rudny Altai and Eastern TransBaikalia.