Abstract

BackgroundThe influence of Pleistocene climatic fluctuations on intraspecific diversification in the Qinling–Daba Mountains of East Asia remains poorly investigated. We tested hypotheses concerning refugia during the last glacial maximum (LGM) in this region by examining the phylogeography of the swelled vent frog (Feirana quadranus; Dicroglossidae, Anura, Amphibia).Methodology/Principal FindingsWe obtained complete mitochondrial ND2 gene sequences of 224 individuals from 34 populations of Feirana quadranus for phylogeographic analyses. Additionally, we obtained nuclear tyrosinase gene sequences of 68 F. quadranus, one F. kangxianensis and three F. taihangnica samples to test for mitochondrial introgression among them. Phylogenetic analyses based on all genes revealed no introgression among them. Phylogenetic analyses based on ND2 datasets revealed that F. quadranus was comprised of six lineages which were separated by deep valleys; the sole exception is that the Main Qinling and Micang–Western Qinling lineages overlap in distribution. Analyses of population structure indicated restricted gene flow among lineages. Coalescent simulations and divergence dating indicated that the basal diversification within F. quadranus may be associated with the dramatic uplifts of the Tibetan Plateau during the Pliocene. Coalescent simulations indicated that Wuling, Daba, and Western Qinling–Micang–Longmen Mountains were refugia for F. quadranus during the LGM. Demographic analyses indicated that the Daba lineage experienced population size increase prior to the LGM but the Main Qinling and the Micang–Western Qinling lineages expanded in population size and range after the LGM, and the other lineages almost have stable population size or slight slow population size decline.Conclusions/SignificanceThe Qinling–Daba Mountains hosted three refugia for F. quadranus during the LGM. Populations that originated in the Daba Mountains colonized the Main Qinling Mountains after the LGM. Recent sharp expansion of the Micang–Western Qinling and Main Qinling lineages probably contribute to their present-day secondary contact.

Highlights

  • Climatic changes associated with Pleistocene glacial cycles are believed to have caused montane species to shift, expand, or contract along latitudinal or elevational gradients [1,2,3]

  • In consistent to this speculation, some bird species probably persisted in its present range including the Qinling–Daba Mountains and southern China mountains south of Yangtze River during the glacial periods and expanded during the warming time [18,19], whereas some herpetology species probably hid into multiple refugia including the south Korea and the regions south of Yangtze River in the southern China during the ice ages [20,21]; but most of them have probably expanded on population size and range during glacial periods before the last glacial maximum (LGM) [18,19]

  • Our knowledge on the influence of the Pleistocene climate changes affecting diversification of the East Asian species is limited to few literatures [18,19,20,21]; further investigations on phylogeography and demography of the montane species in this region are necessary for testing above distinct hypotheses

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Summary

Introduction

Climatic changes associated with Pleistocene glacial cycles are believed to have caused montane species to shift, expand, or contract along latitudinal or elevational gradients [1,2,3]. East Asia was probably characterized by a mosaic of mountains and likely experienced a relatively mild Pleistocene climate [13,14,15], a combination that probably provided stable habitats [16] and glacial refugia for species [17] throughout their entire ranges rather than species being confined only to southern latitudes within their present-day ranges [2,3,6] In consistent to this speculation, some bird species probably persisted in its present range including the Qinling–Daba Mountains and southern China mountains south of Yangtze River during the glacial periods and expanded during the warming time [18,19], whereas some herpetology species probably hid into multiple refugia including the south Korea and the regions south of Yangtze River in the southern China during the ice ages [20,21]; but most of them have probably expanded on population size and range during glacial periods before the last glacial maximum (LGM) [18,19]. We tested hypotheses concerning refugia during the last glacial maximum (LGM) in this region by examining the phylogeography of the swelled vent frog (Feirana quadranus; Dicroglossidae, Anura, Amphibia)

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