Bennettitales in the Rhaetian flora of Wüstenwelsberg, Bavaria, Germany

Abstract

The diverse bennettitalean plant remains from the Rhaetian of Wüstenwelsberg, Franconia, southern Germany, are described by means of macromorphological and epidermal anatomy; the study is part of the ongoing examination of this recently excavated and excellently preserved fossil flora. The taxa identified include four species of Pterophyllum, one species of Anomozamites, two species of Nilssoniopteris and one species of Wielandiella with sterile leaves, bracts and ovulate reproductive organs. In addition, an enigmatic type of bennettitalean microsporangiate organ has been obtained, remains of which from the Rhaetian of Greenland had been assigned to Bennettistemon. However, the material from Wüstenwelsberg is much more complete and is assigned to a new genus, viz. Welsbergia gen. nov., with its type species Welsbergia bursigera (Harris) comb. nov., based on the organ's unique architecture. The microsporangiate organs are always exclusively associated with the sterile foliage Pterophyllum aequale. Comparison of the flora from Wüstenwelsberg with adjacent Rhaetian floras revealed distinct local differences in the bennettitalean constitution, which are discussed in the light of palaeogeography and plant dispersal patterns.