Plant Diversity ›› 2021, Vol. 43 ›› Issue (01): 1-14.DOI: 10.1016/j.pld.2020.09.002

• Articles •    

Molecular phylogeny, biogeography and character evolution of the montane genus Incarvillea Juss. (Bignoniaceae)

Santosh Kumar Ranaa, Dong Luoa, Hum Kala Ranaa,b, Shaotian Chenc, Hang Suna   

  1. a CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
    b University of the Chinese Academy of Sciences, Beijing 100049, China;
    c College of Pharmaceutical Science, Yunnan University of Chinese Medicine, Kunming 650500, China
  • Received:2020-03-17 Revised:2020-09-01 Published:2021-03-25
  • Contact: Shaotian Chen, Hang Sun
  • Supported by:
    The authors thank Dr Zhuo Zhou for his help with the molecular dating analysis, Raymond Porter and Alexander Robert O'Neill (USA) for valuable inputs and English editing, and Dr Niu Yang, YaZhou Zhang, Qia Wang for providing the plant photographs. This study was supported by the Second Tibetan Plateau Scientific Expedition and Research (STEP) Program (2019QZKK0502), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20050203), NSFC-Yunnan joint fund to support key projects (U1802242), the Major Program of the National Natural Science Foundation of China (31590823) and the National Natural Science Foundation of China (31570203).

Abstract: The complex orogeny of the Himalaya and the Qinghai-Tibet Plateau (QTP) fosters habitat fragmentation that drives morphological differentiation of mountain plant species. Consequently, determining phylogenetic relationships between plant subgenera using morphological characters is unreliable. Therefore, we used both molecular phylogeny and historical biogeographic analysis to infer the ancestral states of several vegetative and reproductive characters of the montane genus Incarvillea. We determined the taxonomic position of the genus Incarvillea within its family and inferred the biogeographical origin of taxa through Bayesian inference (BI), maximum likelihood (ML) and maximum parsimony (MP) analyses using three molecular data sets (trnL-trnF sequences, nr ITS sequences, and a data set of combined sequences) derived from 81% of the total species of the genus Incarvillea. Within the genus-level phylogenetic framework, we examined the character evolution of 10 key morphological characters, and inferred the ancestral area and biogeographical history of the genus. Our analyses revealed that the genus Incarvillea is monophyletic and originated in Central Asia during mid-Oligocene ca. 29.42 Ma. The earliest diverging lineages were subsequently split into the Western Himalaya and Sino-Himalaya during the early Miocene ca. 21.12 Ma. These lineages resulted in five re-circumscribed subgenera (Amphicome, Olgaea, Niedzwedzkia, Incarvillea, and Pteroscleris). Moreover, character mapping revealed the ancestral character states of the genus Incarvillea (e.g., suffruticose habit, cylindrical capsule shape, subligneous capsule texture, absence of capsule wing, and loculicidal capsule dehiscence) that are retained at the earliest diverging ancestral nodes across the genus. Our phylogenetic tree of the genus Incarvillea differs from previously proposed phylogenies, thereby recommending the placement of the subgenus Niedzwedzkia close to the subgenus Incarvillea and maintaining two main divergent lineages.

Key words: Biodiversity hotspots, Biogeography, Incarvillea, Molecular phylogeny, Phytools, Stochastic character mapping