New materials of Mariopteris from the Cisuralian of northwestern China and their implications for palaeogeographic diversification.

The genus Mariopteris was widespread throughout Europe and North America throughout most of the Late Palaeozoic. New fossil records of Mariopteris can provide a historical perspective on their evolution and palaeogeographic distributions. Three Mariopteris species, Mariopteris yongchangensis sp. nov., M. hexiensis sp. nov., and M. sp., from the Cisuralian of Shanxi Formation in Yongchang, Gansu Province, northwestern China are described in detail here on the basis of morphological and anatomical characteristics. We are able to deduce that the type species of Mariopteris in the Mississipian and Permian remained rare and simplified but that this taxon diversified in the Pennsylvanian. The fossil records and palaeoclimatic characteristics presented here suggest that the Guadalupian was the end of the dominance of Mariopteris and that this genus was more diverse in tropical environments in the Carboniferous-Permian. [ABSTRACT FROM AUTHOR]