An amended species, Nilssoniopteris neimenguensis nom. nov., from the Lower Jurassic of the Xilinhot Basin, Inner Mongolia, northern China, with a reexamination of Nilssoniopteris species

Abstract

An amended species, Nilssoniopteris neimenguensis (Wang, 1984) Zhao et Deng, nom. nov., is described from the Lower Jurassic Hongqi Formation of the Xilinhot Basin, Inner Mongolia, northern China, based on leaf macromorphology and cuticular structures. Following a reexamination of the specimens published in the previous literature, a total of 86 species of Nilssoniopteris are recognized, and their stratigraphic and geographic distributions are analyzed. Nilssoniopteris first occurs in the Carnian of the Late Triassic of Central Europe and the southwest region of the United States. This genus spreads in the Euro-Sinian region in the Late Triassic and then gradually extends to the Siberian-Canadian region in the Early to Middle Jurassic, where it first experiences diversification and distribution expansion. After a decline in both diversity and geographic range in the Late Jurassic, Nilssoniopteris species flourish and almost completely migrate to the Siberian-Canadian region during the Early Cretaceous, and the genus finally dies out in the Cenomanian of the Late Cretaceous. The paleoclimatic conditions of Nilssoniopteris also experience a change from the subtropical-tropical zone to the warm temperate zone, indicating that the species may have grown in the warm humid temperate and subtropical-tropical zones with a general preference for warm, humid climates.