Unveiling the evolution of the Kungurian (Cisuralian) flora in the paleotropics (Southern Alps, Northern Italy)

Abstract

The end of the Late Paleozoic Ice Age is associated with a distinct vegetation turnover that gradually replaced wetland forests with a vegetation dominated by drought tolerant plants. The Kungurian plant fossil and sporomorph assemblages of the Southern Alps are among the most rich, diverse and well-dated from the Cisuralian paleotropics. The integration of recently studied and unpublished plant macrofossil and sporomorph assemblages from the Athesian Volcanic District and the review of historical collections provides a comprehensive and up to date paleobotanical dataset of the Cisuralian in the Southern Alps. This allows to trace almost continuously the evolution of the flora throughout the Kungurian. From the here presented overview new main aspects emerge, such as: i) the earliest occurrences for some main group of plants, including taxa previously reported only from the late Permian; ii) the so far oldest co-occurrences of walchian and voltzian conifers during the early Kungurian; iii) the increase in diversity and abundance of voltzian conifers and sphenopterids throughout the Kungurian; iv) the presence of putative endemic taxa in different groups of gymnosperms, and eventually, v) the establishment of a stable, rich and diverse gymnosperm-dominated flora from the middle Kungurian onwards, which, despite occasional wildfires, prospered until the late Kungurian.