Monograptus deubeli and praedeubeli (Wenlock,Silurian) in the Asian part of the former Soviet Union

Koren', T. N., & Suyarkova, A. A., 1994:03:28. Monograptus deubeli and praedeubeli (Wenlock, Silurian) in the Asian part of the former Soviet Union. Alcheringa 18, 000–000. ISSN 0311-5518.

During the last decade the sequence and composition of the later Homerian (Wenlock) graptolite fauna has become comparatively well known in many regions of the world. A complete and detailed graptolite biozonation has been elaborated in Europe, and partly confirmed in Australia and Arctic Canada. Valuable new data have been obtained from several widely scattered areas within the Asian part of the former U. S. S. R. M. praedeubeli Jaeger (rare) and M. deubeli (common) have been found in the Homerian sequences in the Novosibirsk Islands and Novaya Zemlya, as well as in the southern Urals and the Turkestan-Alai Mountains of central Asia. In sections studied here, especially in the Alai Range, both species have well defined stratigraphic ranges in a variety of pelagic and hemipelagic facies. Their well established taxonomy based on sicular shape and thecal structure allows their recognition in material of different preservation. They belong to a single phylogenetic line and can be used as important biostratigraphic markers for interregional correlation, especially considering the distinct differences in the composition of associated monograptids. Thus, members of the Pristiograptus idoneus—Lobographu? claudiae lineage parallelling the development of M. praedeubeli and M. deubeli in the Homerian of central Asia, Australia, Arctic Canada and Arctic Russia are unknown from European and northern African sections.