Seed ferns and cycads in the Rhaetian flora of Wüstenwelsberg, Bavaria, Germany

Abstract

The diverse seed fern and cycad plant remains from the Rhaetian of Wüstenwelsberg (Franconia, southern Germany) are described by means of macromorphological anatomy and cuticular characteristics. The study is part of the ongoing examination of this recently excavated and excellently preserved fossil plant assemblage. In total, six species of seed ferns have been identified including Lepidopteris (1 species with male and female reproductive organs; Peltaspermales), Pachypteris (1 species; Umkomasiales), Rhaphidopteris (1 species), Ptilozamites (2 species) and Hydropterangium (1 species, a male reproductive organ); some dispersed seeds were described as Carpolithes sp. Cycads (including Nilssoniales) contain Nilssonia (1 species), Doratophyllum (1 species), Ctenis (1 species), Pseudoctenis (2 species). Four Thinnfeldia species have to be recombined into Pachypteris species in the course of the study for reasons of nomenclatorial priority. The comparison of the flora from Wüstenwelsberg with adjacent Rhaetian floras revealed distinct local differences in the seed fern and cycad portion of the respective floras, which are discussed in the light of palaeogeography involving dispersal patterns or mechanisms and adaptations of the plants.