Plant Diversity ›› 2021, Vol. 43 ›› Issue (06): 480-491.DOI: 10.1016/j.pld.2020.12.006

• Articles • Previous Articles     Next Articles

Fossil fruits of Firmiana and Tilia from the middle Miocene of South Korea and the efficacy of the Bering land bridge for the migration of mesothermal plants

Lin-Bo Jiaa, Gi-Soo Namb, Tao Suc,d, Gregory W. Stulle,f, Shu-Feng Lic, Yong-Jiang Huanga, Zhe-Kun Zhoua   

  1. a CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China;
    b Gongju National University of Education, 27, Ungjin-ro, Gongju-si, Chungcheongnam-do 32553, South Korea;
    c CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China;
    d University of the Chinese Academy of Sciences, Beijing 100049, China;
    e Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China;
    f Department of Botany, Smithsonian Institution, Washington, DC 20013, USA
  • Received:2020-10-23 Revised:2020-12-08 Online:2021-12-25 Published:2022-01-11
  • Contact: Lin-Bo Jia, Yong-Jiang Huang
  • Supported by:
    We are grateful to the Herbarium of the Institute of Botany (PE) and the Herbarium of the Kunming Institute of Botany (KUN), Chinese Academy of Sciences (CAS) for providing access to comparative specimens. This work was supported by the National Natural Science Foundation of China (No. 31900194), the Foundation of the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (No. 183112), the Yunnan Province Natural Science Foundation (No. 2019FB061), the "Light of West China" Program, CAS, and the Youth Innovation Promotion Association, CAS (No. 2017439).

Abstract: Determining whether the high-latitude Bering land bridge (BLB) was ecologically suitable for the migration of mesothermal plants is significant for Holarctic phytogeographic inferences. Paleobotanical studies provide a critical source of data on the latitudinal positions of different plant lineages at different times, permitting assessment of the efficacy of the BLB for migration. Here we report exceptionally preserved fossils of Firmiana and Tilia endochrysea from the middle Miocene of South Korea. This represents a new reliable record of Firmiana and the first discovery of the T. endochrysea lineage in the fossil record of Asia. The occurrence of these fossils in South Korea indicates that the two lineages had a distribution that extended much farther north during the middle Miocene, but they were still geographically remote from the BLB. In light of the broader fossil record of Asia, our study shows that, in the middle Miocene, some mesothermal plants apparently inhabited the territory adjacent to the BLB and thus they were possibly capable of utilizing the BLB as a migratory corridor. Some other mesothermal plants, such as Firmiana and the T. endochrysea lineages, however, are restricted to more southern regions relative to the BLB based on current fossil evidence. These lineages may have been ecologically unable to traverse the BLB, which raises questions about the efficacy of the BLB as a universal exchange route for mesothermal plants between Asia and North America during the middle Miocene.

Key words: Asia, Bering land bridge, Biogeography, Middle Miocene, Malvaceae