The Rhaetian flora of Wüstenwelsberg, Bavaria, Germany: Description of selected gymnosperms (Ginkgoales, Cycadales, Coniferales) together with an ecological assessment of the locally prevailing vegetation

Abstract

This paper describes the ginkgoaleans (Ginkgoites) and conifers (Palissya, Stachyotaxus, Schizolepis) of the Rhaetian flora from Wüstenwelsberg, as well as a new species of the cycad Becklesia. The ginkgophyte leaf fragments are very abundant in certain levels (‘Blätterkohle‘) whereas conifers are common in the main fossiliferous bed. The Wüstenwelsberg specimens extend the range for Ginkgoites taeniatus from the Hettangian to the Rhaetian and for the genus Becklesia from the Cretaceous to the Rhaetian. The other elements are typical for the Rhaetian floras of Bavaria and often also of the Northern Hemisphere. A comparison with other Northern Hemisphere plant assemblages demonstrates a high similarity with the Rhaetian floras from Jameson Land (Greenland) and Scania (Sweden) but significant differences to the Hettangian floras from adjacent areas in Franconia, especially at species and sometimes at generic level. A comparison with the microflora from the same sections shows a hidden diversity that is highest in small herbaceous plants (mosses, lycophytes, ferns) and in the conifers. Wüstenwelsberg reflects, thus, an articulated landscape with a high water and nutrients availability (stagnant water bodies and/or river systems) covered by a complex and multi-storeyed vegetation shown, among others, by the general abundance in hygrophytic spores and high diversity among the various plant groups. This must have corresponded to one of the humid episodes that characterized the generally warm and arid climate of the Rhaetian of Europe.