Abstract

The validity and index species of the standard ammonite-based zones (from bottom to top: Rjasanensis, Spasskensis, and Tzikwinianus zones) of the Ryazanian Stage in the type region are discussed. The species Surites spasskensis (Nikitin, 1888) and S. tzikwinianus (Bogoslowsky, 1896) are re-examined and re-described. It has been established that these two phylogenetically successive species characterize two adjacent intervals of the geological section. For the first time, photographs of holotypes (by monotypy) of these species and of the lectotype of Riasanites rjasanensis (Nikitin, 1888) are published.

中文翻译：

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论俄罗斯地台梁赞阶标准尺度的地带性指标种

摘要

讨论了该类型区梁赞阶标准菊石基带（自下而上：Rjasanensis、Spasskensis和Tzikwinianus带）的有效性和指标种。对Surites spasskensis (Nikitin, 1888) 和S. tzikwinianus (Bogoslowsky, 1896) 进行了重新检查和重新描述。已经确定，这两个系统发育上连续的物种表征了地质剖面的两个相邻区间。这些物种的正模（单型）和Riasanites rjasanensis (Nikitin, 1888)选型的照片首次发表。