Fossil dipterid fern Thaumatopteris in China: new insights of systematics, diversity and tempo-spatial distribution patterns

ABSTRACT

Thaumatopteris (Goeppert) Nathorst is a typical dipterid fern in the early Mesozoic, showing global significances for palaeoclimate, phytogeography and biostratigraphy. However, the detailed understanding on the relationship between species diversity and the environmental background of this genus is still unclear. Here, we reinvestigated new collections and type specimens of Thaumatopteris contracta Li et Tsao collected from the Upper Triassic of Yunnan Province, and analysed the systematic, diversity variations and tempo-spatial distribution patterns of Thaumatopteris in China. An emendation was proposed for species diagnosis of Thaumatopteris contracta based on both sterile and fertile pinnae. Our analysis demonstrates that the genus Thaumatopteris reached a higher diversity and differentiation with 11 species during the Late Triassic in China and suffered a severe loss of species diversity across the Triassic-Jurassic transition. Changes in the spatial distribution pattern of Thaumatopteris demonstrate an ecological response to local environment degradation in the Upper Yangtze region. The destruction of habitat and the block of the transport channel of warm moist flow from the Tethys Ocean caused by the Indosinian tectonic movement, especially, the uplift of the Longmen Mountains may represent the potential environmental trigger.

KEYWORDS:

• Thaumatopteris
• diversity
• tempo-spatial distributions
• Mesozoic
• China

Acknowledgments

We appreciate Prof. Mihai E. Popa and other anonymous reviewer for carefully reviewing the manuscript and made helpful comments and suggestions. We would like to thank Prof. Xiangwu Wu and Dr Chong Dong from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences for the suggestions regarding the manuscript. We are grateful to Mr Daojun Yuan for his help in preparing original collections of genus Thaumatopteris housed in Palaeobotany Collection of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported from the Strategic Priority Program (B) of the Chinese Academy of Sciences (XDB 18000000 and 26000000), the National Natural Sciences Foundation of China (Grant Nos. 41572014, 41790454, 41702004 and 41688103), the State Key Program for Basic Research and Development of the Ministry of Science and Technology of China (2016YSC0600406), and State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS) (Grant Nos. 20172103, 20191103 and 183126).