J Syst Evol ›› 2023, Vol. 61 ›› Issue (6): 1065-1078.DOI: 10.1111/jse.12934

• Research Articles • Previous Articles     Next Articles

Herbaceous eudicot Fairlingtonia from the Lower Cretaceous of Jiuquan Basin, Northwest China and its radiation in Laurasia

Bao-Xia Du1*, Ming-Zhen Zhang2,3*, Jing Zhang1, Ai-Jing Li1, Shao-Hua Lin1, Guo-Rong Ma1, and Jian-Guo Hui1   

  1. 1 Key Laboratory of Mineral Resources in Western China, Gansu Province, Lanzhou University, Lanzhou 730000, China;
    2 Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
    3 Key Laboratory of Petroleum Resources, Gansu Province, Lanzhou 730000, China
    *Authors for correspondence. Bao-Xia Du. E-mail: dubx@lzu.edu.cn; Ming-Zhen Zhang. E-mail: zhangmzh08@lzb.ac.cn
  • Received:2022-06-19 Accepted:2022-11-01 Online:2022-11-15 Published:2023-11-01

Abstract: Eudicots exhibit diverse life forms and occupy a wide variety of habitats in the modern terrestrial ecosystems, and the diversification began during the Early Cretaceous; however, few Early Cretaceous fossils are preserved as multiorgan whole plants that can provide sufficient morphological characters for detailed phylogenetic assessment. Here, Fairlingtonia microgyna sp. nov. is reported from the upper Lower Cretaceous of Zhonggou Formation, Hanxia Section, Yumen City, western Gansu Province, Northwest China. The specimen is exceptionally preserved as multiorgan whole plant fossil with fibrous adventitious roots, simple and deeply dissected leaves, solitary and dehiscent capsular fruits attached to the creeping stems. As such, it was interpreted as a herbaceous eudicot. Phylogenetic analyses support a placement within the Papaveraceae, most likely in Papaveroideae, but there are obvious differences in morphological characteristics, which cannot confirm the systematic position within the Papaveraceae. Fossil records of Fairlingtonia from contemporaneous deposits (late Aptian to early Albian) in Northwest China and eastern North America provide direct evidence of the geographical radiation of Fairlingtonia on Laurasia. And the morphological characters of F. microgyna, including creeping leafy branches, fibrous adventitious roots, small and deeply dissected leaves as well as small capsular fruits with tiny seeds probably indicate that it was a colonizer of lake-shore environments under wet and bright conditions and possessed fast-growing and rapid propagation habitats, which allowed it to expand its geographic range with both sexual and asexual reproduction.

Key words: Fairlingtonia, late Early Cretaceous, Laurasia, Northwest China, radiation