Hierarchical population structure and phylogeographic divergence in the Korean endemic salamander Hynobius notialis

Vollständiger Abstract

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Abstract Amphibian populations are strongly influenced by geographical and environmental barriers; however, the processes shaping the spatial genetic structure remain poorly understood in many East Asian taxa. We investigated the population structure and evolutionary history of the Korean endemic salamander Hynobius notialis using 25 microsatellite loci and mitochondrial cytb sequences from 200 individuals across 12 locations on the southern Korean Peninsula. Microsatellite data revealed hierarchical genetic structuring associated with rivers, mountain ranges, coastal boundaries and palaeodrainage systems. Mitochondrial DNA analyses showed deep lineage divergence and strong population differentiation together with isolation-by-environment signals. Despite evidence of recent gene flow inferred from microsatellites, mitochondrial haplotypes showed limited sharing among populations, resulting in pronounced mito-nuclear discordance. These contrasting patterns suggest that nuclear and mitochondrial markers capture different temporal and evolutionary processes shaped by historical isolation, secondary contact, sex-biased dispersal and potentially selective forces. Our findings demonstrated that both historical landscape dynamics and environmental heterogeneity contribute to population divergence in H. notialis, highlighting the importance of integrating multiple genetic markers and landscape perspectives in amphibian phylogeography.