Moscovian age

The Moscovian Stage was introduced by Sergei Nikitin (1851–1909) in 1890, using brachiopods in the Moscow Basin of European Russia. Nikitin named the stage after Moscow, then a major city and now the capital of Russia. The base of the Moscovian is close to the first appearances of the conodonts Declinognathodus donetzianus and Idiognathoides postsulcatus or otherwise the fusulinid Aljutovella aljutovica. Because the fusulinid species are regionally different, they can not be used for worldwide correlation. A Global Boundary Stratotype Section and Point for the Moscovian Stage has yet to be defined (2008). A proposal is to use the first appearance of the conodont Diplognathodus ellesmerensis, but since the species is rare and its evolution relatively unknown, it has not been accepted yet. The top of the Moscovian (base of the Kasimovian) is at the base of the fusulinid biozone of Obsoletes obsoletes and Protriticites pseudomontiparus, or with the first appearance of the ammonite genus Parashumardites. ==Subdivisions==

In European Russia and Eastern Europe, where the stage was first recognized, the Moscovian is subdivided into four regional substages: Vereiskian, Kashirskian, Podolskian, and Myachkovskian, named after towns near Moscow (Vereya, Kashira, Podolsk, and Myachkovo). The Moscovian can biostratigraphically be divided into five conodont biozones: • Neognathodus roundyi and Streptognathodus cancellosus Zone • Neognathodus medexultimus and Streptognathodus concinnus Zone • Streptognathodus dissectus Zone • Neognathodus uralicus Zone • Declinognathodus donetzianus Zone ==References==