J Syst Evol

• Research Article •    

Biogeographic analysis based on phylogenomic data supports multiple ancient dispersals that facilitated the eastern Asia–North America–Mexico disjunction in the subfamily Linnaeoideae (Caprifoliaceae)

Hong‐Xin Wang1,2, Diego F. Morales‐Briones3, Jacob B. Landis4,5, Jun Wen6, and Hua‐Feng Wang1*   

  1. 1 Sanya Nanfan Research Institute of Hainan University, Collaborative Innovation Center of Nanfan and High‐Efficiency Tropical Agriculture, Sanya 572025, Hainan, China;
    2 Zhai Mingguo Academician Work Station, Sanya University, Sanya 572000, Hainan, China;
    3 Princess Therese von Bayern chair of Systematics, Biodiversity and Evolution of Plants, Ludwig‐Maximilians‐Universität München, 80638 Munich, Germany;
    4 School of Integrative Plant Science, Section of Plant Biology and the L.H. Bailey Hortorium, Cornell University, Ithaca, NY 14850, USA;
    5 BTI Computational Biology Center, Boyce Thompson Institute, Ithaca, NY 14853, USA;
    6 Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013‐7012, USA
    *Author for correspondence. E‐mail: hfwang@hainanu.edu.cn.
  • Received:2022-07-11 Accepted:2023-10-20 Online:2023-12-18

Abstract: The small subfamily Linnaeoideae of Caprifoliaceae exhibits a disjunct distribution in Eurasia and North America, including Mexico, with most taxa occurring in eastern Asia or Mexico and the monospecific Linnaea Gronov. ex L. having a circumboreal to north temperate distribution. We sampled 17 of the 20 species representing all Linnaeoideae genera and used nuclear (target enrichment) and complete plastome sequence data to reconstruct the phylogeny. Our results show strong topological conflicts between nuclear and plastid data, especially concerning Dipelta Maxim. and Diabelia Landrein, supporting hybridization events complicating the deep diversification. Nuclear data were used for divergence time estimation and ancestral area reconstruction. The divergence time between the Mexican Vesalea M. Martens & Galeotti and the Linnaea clade was dated to 39.5 Ma, with a 95% highest posterior density of 28.2 Ma (mid-Oligocene) to 45.2 Ma (mid-Eocene). Reconstructed ancestral areas support a widespread common ancestor of Linnaea plus Vesalea in Mexico and at least another area (eastern Asia, North America, or Europe). The biogeographic analysis, including fossils, supports the ancestral range of Linnaeoideae to be widespread in central and western China + Europe + Mexico, or eastern and northern Asia + central and western China + Mexico, or central and western China + North America + Mexico. The North Atlantic and/or the Bering land bridges may be important in the widespread distribution across continents in the Northern Hemisphere. Our study highlights the importance of utilizing fossils in biogeographic inferences andusing data from different genomes while reconstructing deep and shallow phylogenies of organisms.

Key words: biogeography, divergence time estimation, Linnaeoideae, phylogenomics