J Syst Evol ›› 2023, Vol. 61 ›› Issue (2): 284-298.DOI: 10.1111/jse.12919

• Research Articles • Previous Articles     Next Articles

Phylogenomic, morphological, and niche differentiation analyses unveil species delimitation and evolutionary history of endangered maples in Acer series Campestria (Sapindaceae)

Xiao‐Kai Fan1, Jing Wu1, Hans Peter Comes2, Yu Feng3, Ting Wang4, Shu‐Zhen Yang5, Takaya Iwasaki6, Hong Zhu7, Yun Jiang8, Joongku Lee9, and Pan Li1*   

  1. 1 Systematic and Evolutionary Botany and Biodiversity Group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
    2 Department of Biosciences, University of Salzburg, Salzburg A-5020, Austria
    3 CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
    4 Hangzhou Botanical Garden(Hangzhou West Lake Academy of Landscape Science), Hangzhou 310013, China
    5 Zhejiang Tianmushan National Nature Reserve Management Bureau, Hangzhou 311311, China
    6 Natural Science Division, Faculty of Core Research, Ochanomizu University, Tokyo 112-8610, Japan
    7 Zhejiang Forestry Academy, Hangzhou 310023, China
    8 Eastern China Conservation Centre for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai 201602, China
    9 Department of Environment and Forest Resources, Chungnam National University, Daejeon 34134, South Korea
    *Author for correspondence. E‐mail: panli@zju.edu.cn
  • Received:2022-05-10 Accepted:2022-09-27 Online:2022-09-29 Published:2023-03-01

Abstract: Accurate species delimitation is crucial for biodiversity conservation. The Acer series Campestria comprises four species, A. campestre L., A. miyabei Maxim., A. miaotaiense P. C. Tsoong, and A. yangjuechi Fang & P. L. Chiu. To clarify controversies over the taxonomic status of the latter three endangered species, we undertook phylogenomic, morphological, and niche differentiation analyses in series Campestria. Our coalescent species tree of 544 and 77 single-copy nuclear genes supported series Campestria as monophyletic, with A. yangjuechi having the closest relationship with A. miaotaiense. However, in the plastome-derived tree based on 64 protein coding sequences, the four species did not cluster together, and each of them grouped with some other sympatric Acer species. Given this nuclear-cytoplasmic conflict, we hypothesize that A. yangjuechi have been subject to nuclear gene introgression and plastid (pt) capture involving another sympatric maple, that is, A. amplum Rehder. Principal component analysis and machine learning based on morphological data could not separate A. yangjuechi and A. miaotaiense, but they both could be clearly distinguished from A. miyabei. Moreover, the niche overlap tests of the two more widespread species, A. miyabei and A. miaotaiense, showed they clearly occupy distinct niches. Overall, we conclude that A. miyabei and A. miaotaiense are distinct species, while A. yangjuechi (endemic to Mt. Tianmu/East China) should be treated as a subspecies of A. miaotaiense. Our study points out that multiple lines of phylogenomic, morphological, and ecological evidence prove highly useful in species delimitation. Additionally, our results should help to inform conservation measures for endangered species of the genus Acer/series Campestria in East Asia.

Key words: Acer, deep learning, ecological niche, multiomics, phylogeny, series Campestria, systematics