Aspects of Permian palaeobotany and palynology. XI. On the recognition of true peltasperms in the Upper Permian of Western and Central Europe and a reclassification of species formerly included in Peltaspermum Harris

Abstract

Foliage and ovuliferous organs of a Late Permian representative of the family Peltaspermaceae are described and discussed. The sterile foliage belongs to the well known species Lepidopteris (al. Callipteris) martinsii (Germar) Townrow. Correlated ovuliferous organs consist of radially symmetrical peltate discs, assign able to the form-genus Peltaspermum Harris. In this study emphasis has been given to the recognition of natural taxa. Detailed study of foliage correlated with the formgenus Peltaspermum has resulted in an emendation of the genus and its promotion to a natural status. The classification of species previously included in Peltaspermum is also discussed. Two other natural genera of the family Peltaspermaceae are discussed, viz. Peltaspermopsis Gomankov emend. and Meyenopteris nov. gen. Dispersed radially symmetrical ovuliferous discs of peltaspermaceous affinity, which cannot be interpreted in terms of natural taxa, are transferred to the form-genus Lopadangium Zhao. Autuniopsis nov. gen. is established as a form-genus for bilaterally symmetrical ovuliferous discs of peltaspermaceous affinity. The following combinations are formally introduced: Peltaspermum martinsii (Germar) nov. comb., P. ottonis (Göppert) nov. comb., Meyenopteris natalensis (Thomas) nov. comb., Lopadangium dafengshanense (Wang Ziq. et Wang Lix.) nov. comb. L. madygenicum (Dobruskina) nov. comb., L petchoricum (Chramova) nov. comb., L. usense (Dobruskina) nov. comb. and Autuniopsis dzungarica (Salmenova) nov. comb. The diagnosis of Peltaspermum martinsii is given and since foliage and ovuliferous organs have previously been described under various names a synonymy list is given. The frond architecture, variation in pinnule morphology and epidermal anatomy, palaeoecology and geographical distribution of Peltaspermum martinsii are discussed and the species is compared with other Late Permian callipterids.