A new leptosporangiate fern Oligosporangiopteris zhongxiangii gen. and sp. nov. from the lowermost Permian of Inner Mongolia, China - morphology, anatomy and reproductive organs

This study focuses on a new leptosporangiate fern Oligosporangiopteris zhongxiangii gen. and sp. nov. from the in situ tuff flora located in the upper part of the Taiyuan Formation (lowermost Permian), Wuda coalfield, Inner Mongolia, North China. We propose a whole-plant concept based on specimens that represent various parts of the plant. Petioles of the new fern are characterized by a tangentially elongated, slightly curved, barshaped xylem strand that has four protoxylem strands on the concave side. Protoxylem strands occur in pairs located close to the lateral xylem ends and the xylem has endarch maturation. The pinna rachis shows a similar anatomy, whereas pinnules are of the cladophleboid type bearing Oligocarpia type of sporangia: sod consisting of 4-8 sporangia.The microspores represent the smallest in situ record of the genus Granulatisporites. The unique combination of the rachial anatomy together with the reproductive organs with in situ spores justifies the creation of Oligosporartgiopteris zhongxiangii gen. and sp. nov. In addition, the new combination Oligocarpia wudaensis (Deng, Sun and Li) comb. nov. is proposed. (C) 2021 Published by Elsevier B.V.

Automated summary

This study presents a new leptosporangiate fern species, Oligosporangiopteris zhongxiangii gen. and sp. nov., from the in situ tuff flora in the Wuda coalfield, Inner Mongolia, North China. The plant's unique anatomy and reproductive organs with in situ spores justify the creation of this new species, as well as the proposal of a new combination, Oligocarpia wudaensis (Deng, Sun and Li) comb. nov.