ISSN 08695938, Stratigraphy and Geological Correlation, 2014, Vol. 22, No. 1, pp. 1–27. © Pleiades Publishing, Ltd., 2014. Original Russian Text © V.V. Silantiev, 2014, published in Stratigrafiya. Geologicheskaya Korrelyatsiya, 2014, Vol. 22, No. 1, pp. 3–30. 1 INTRODUCTION Through the European part of Russia (East Euro pean and Timan–Pechora Platforms, Uralian fore deep), nonmarine bivalves are widespread in sequences of the Ufimian, Kazanian, Severodvinian, and Vyatkian stages of the Permian System (Fig. 1). Bivalve shells, casts, and impressions frequently occur together with ostracod, fish, and terrestrial vertebrate remains, i.e., with faunal groups which were recently used for development and/or specification of zonal scales (Golubev, 2000; Molostovskaya, 2005; Kukhti nov et al., 2008; Minikh, A.V. and Minikh, M.G., 2009; Newell et al., 2010). Despite the wide distribution and sufficient knowl edge of these fossils, only several regional (Amalitzky, 1892a; Kanev, 1985, 1994; Gusev, 1990, 1996c) and local (Silantiev, 1996a) zonal scales were proposed on the basis of bivalves during the last 120 years. In most of these works, their authors indicated only species assem blages (paleocoenoses, assemblages, faunas) character istic of particular stratigraphic units (Nechaev, 1894; Gusev, 1963, 1977a; Kuleva, 1980; Silantiev, 1995, 2001; Silantiev and Kurkova, 2009; etc.). The development of zonal scales based on nonma rine bivalves encounters difficulties determined by the requirements for such scales: primarily their continu ity, unambiguous position of boundaries between zones, and succession of assemblages from contiguous zones through the section (Stratigraficheskii…, 2006, Article VII.3). These difficulties are explained by the complex structure of terrestrial formations, some evo lutionary conservatism of nonmarine bivalves, their multifunctional variability, and facies control in sec tions, as well as by different approaches to their taxon omy (Betekhtina, 1974; Gusev, 1990). To solve these problems, a uniform technique was proposed in (Silantiev, 2010) for the study of Late Paleozoic non marine bivalves, which takes into consideration all the external, internal, and microstructural features of their shells. The longterm revision of available collections of nonmarine bivalves from many localities in Russia provides grounds for development of a zonal scale based on this faunal group. In this regard, success may be achieved only on the basis of species from the genus Palaeomutela Amalitzky, 1891, whose diversity and stratigraphic distribution most completely satisfy the requirements of the Stratigraphic Code of Russia (Stratigraficheskii…, 2006). In this connection, the main tasks of this work were as follows: (1) taxonomic revision of the genus Palaeomutela; (2) revelation of main evolutionary lineages in its development; (3) analysis of sections for establishing successions of first appearances of species and their stratigraphic ranges; (4) selection of index species; (5) complex paleontological substantiation of zones; (6) standard description of zonal units. Permian Nonmarine Bivalve Zonation of the East European Platform V. V. Silantiev Kazan (Volga Region) Federal University, ul. Kremlevskya 16, Kazan, 420008 Russia email: vladimir.silantiev@ksu.ru Received October 12, 2012 Abstract—New finds and revision of available collections of nonmarine bivalves provided grounds for devel opment of a zonal scale for terrestrial sequences of the Permian System based on species belonging to the genus Palaeomutela Amalitzky, 1891, which are characterized by regular changes in the structure of the shell hinge. The scale includes two parallel zonal successions that are based on the stratigraphic distribution and evolutionary trends of two morphological lineages of the genus. The zonal succession based on development of the P. umbonata group (dwellers of mobile waters and silty–psammitic substrates) includes 11 range zones: stegocephalum, ovatiformis, umbonata, quadriangularis, krotowi, wohrmani, numerosa, ulemensis, keyser lingi, curiosa, golubevi. The zonal succession based on development of the P. castor group (dwellers of calm waters and silty–pelitic substrates) includes eight range zones: larae, castor, olgae, doratioformis, marposad ica, fischeri, obunca, amalitzkyi. The proposed zonal units are correlated with scales based on ostracod, fish, and tetrapod fossils. New species Palaeomutela golubevi sp. nov. and P. amalitzkyi sp. nov. are described with the extended diagnosis of the genus Palaeomutela. Keywords: nonmarine bivalves, zonal scale, Permian, East European Platform DOI: 10.1134/S0869593814010067