title: Incipient speciation with gene flow on a continental island: Species delimitation of the Hainan Hwamei (Leucodioptron canorum owstoni, Passeriformes, Aves).
abstract: Because of their isolation, continental islands (e.g., Madagascar) are often thought of as ideal systems to study allopatric speciation. However, many such islands have been connected intermittently to their neighboring continent during recent periods of glaciation, which may cause frequent contact between the diverging populations on the island and continent. As a result, the speciation processes on continental islands may not meet the prerequisites for strictly allopatric speciation. We used multiple lines of evidence to re-evaluate the taxonomic status of the Hainan Hwamei (Leucodioptron canorum owstoni), which is endemic to Hainan, the largest continental island in the South China Sea. Our analysis of mitochondrial DNA and twelve nuclear loci suggests that the Hainan Hwamei can be regarded as an independent species (L. owstoni); the morphological traits of the Hainan Hwamei also showed significant divergence from those of their mainland sister taxon, the Chinese Hwamei (L. canorum). We also inferred the divergence history of the Hainan and Chinese Hwamei to see whether their divergence was consistent with a strictly allopatric model. Our results suggest that the two Hwameis split only 0.2 million years ago with limited asymmetrical post-divergence gene flow. This implies that the Hainan Hwamei is an incipient species and that speciation occurred through ecologically divergent selection and/or assortative mating rather than a strictly allopatric process.
authors.affiliation: Ministry of Education Key Laboratory for Tropical Plant and Animal Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China. Electronic address: ningwang83@hotmail.com.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: Ministry of Education Key Laboratory for Tropical Plant and Animal Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
authors.affiliation: Ministry of Education Key Laboratory for Tropical Plant and Animal Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan.
authors.forename: Chia-Fen
authors.initials: CF
authors.lastname: Yeh
authors.affiliation: State Key Laboratory of BioControl, College of Ecology and Evolution/School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Forestry Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Ministry of Education Key Laboratory for Tropical Plant and Animal Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
authors.affiliation: High-Altitude Experimental Station, Taiwan Endemic Species Research Institute, Chi-chi 55244, Taiwan.
authors.forename: Cheng-Te
authors.initials: CT
authors.lastname: Yao
authors.affiliation: Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan. Electronic address: t43028@ntnu.edu.tw.
authors.forename: Shou-Hsien
authors.initials: SH
authors.lastname: Li
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D051456:Gene Flow; D049810:Genetic Speciation; D005843:Geography; D062312:Islands; D016013:Likelihood Functions; D008270:Madagascar; D008297:Male; D046109:Passeriformes / Q000235:genetics*; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial
keywords: Continental island; Incipient speciation; Post-divergence gene flow; Species delimitation