Abstract
A new fossil plant community is documented from the Upper Shihhotse Formation on the North China Block with an extremely unusual composition and diversity. Zircon U–Pb dating yields an age of 268.3 ± 2.3 Ma during the mid-Roadian to early Wordian stages of the Guadalupian. The community occurs in two beds and is dominated by fossils of the gymnosperm family Nystroemiaceae, which account for up to 99% of specimens recovered and comprise stems, branches, roots, ovuliferous complexes of Nystroemia pectiniformis and N. sp., and leaves of Chiropteris reniformis. The two different species of Nystroemia are distinguished on size and apical features of ovules, with N. pectiniformis having two apical bicornuate horns, whereas N. sp. has apical auricular extensions. Leaves of C. reniformis are megaphyllous and possess a long petiole and net venation. In the Cathaysian flora, different species of Nystroemiaceae are distinguished by features of their ovules and habit, but all bear leaves of C. reniformis which suggests evolutionary modularity and different rates of evolution between the ovules and leaves. Both N. pectiniformis and N. sp. are shown to have been short, uptight trees. Sedimentary evidence shows the community grew in a meandering fluvial setting with repeated river channel changes. Compared with contemporaneously diverse Cathaysian floral communities in the Upper Shihhotse Formation, the vegetation has a very restricted diversity and is a rare occurrence of a gymnosperm-dominated community. The Nystroemiaceae demonstrates an r-selective ecological strategy as pioneering plants adapted to living in unstable habitats and newly opened gaps in the riparian zone.
Original language | English |
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Article number | 104918 |
Number of pages | 17 |
Journal | Review of Palaeobotany and Palynology |
Volume | 316 |
Early online date | 29 May 2023 |
DOIs | |
Publication status | Published - Sept 2023 |
Bibliographical note
Funding Information:This paper is dedicated to Prof. Zhiyan Zhou for his important contributions to the Chinese palaeobotany, especially in recognition of his pioneering studies on the Ginkgoales. We thank Professor Bainian Sun (Lanzhou University, China) for locality information, and Dr. Qing Ma (China Petroleum University) for suggestions with the LA-ICP-MS Zircon U–Pb dating, Mr. Shengwu Mei (Nanjing Institute of Geology and Palaeontology, NIGPAS) for field work assistance, and Ms. Jingjing Tang (NIGPAS) for photographic help. We thank Profs. Hans Kerp and Zhuo Feng for detailed reviews that helped improve the present paper. This work is funded by the State Key Laboratory of Palaeobiology and Stratigraphy (No. 20201103 ), the National Science Foundation of China (No. 41872013 ), and the Strategic Priority Research Program (B) of Chinese Academy of Sciences (No. XDB26000000 ).
Publisher Copyright:
© 2023
Keywords
- Cathaysian flora
- Chiropteris
- Nystroemia
- Ovule
- Palaeoecology
- R-selective
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Palaeontology