Earliest Triassic (Induan) megaspores from Moscow Syneclise, Russia: taxonomy and stratigraphy

Abstract

This study describes the megaspore assemblages from the Ryabinsk Member of the Vokhma Formation of the Moscow Syneclise. The genus Otynisporites is emended, three new species, Maexisporites meditectatus, M. rugulaeferus and Otynisporites maculosus, are erected, and one new combination, Maexisporites grosstriletus, is proposed. Megaspore descriptions relate the gross morphology and fine structure of the exine surface of thirteen taxa. From the appearance of the exine surface and ornamentation processes, it appears that some forms currently included in certain genera according to their morphological features do not belong to them. The assemblage from Sholga is evidently of low diversity at the generic level, possibly reflecting the end-Permian biotic crisis. The composition of the megaspore assemblages indicates their Induan age.