Isolation in habitat refugia promotes rapid diversification in a montane tropical salamander

Authors

  • Gabriela Parra-Olea,

    Corresponding author
    1. Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal 04510, México
      Gabriela Parra-Olea, Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal 04510, México.
      E-mail: gparra@ibiologia.unam.mx
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  • Juan Carlos Windfield,

    1. Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal 04510, México
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  • Guillermo Velo-Antón,

    1. Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal 04510, México
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    • Present address: CIBIO – Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão, R. Padre Armando Quintas, 4485-661 Vairão, Portugal.

  • Kelly R. Zamudio

    1. Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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Gabriela Parra-Olea, Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal 04510, México.
E-mail: gparra@ibiologia.unam.mx

Abstract

Aim  Our goal was to reconstruct the phylogenetic history and historical demography of highly divergent populations of the endemic plethodontid salamander Pseudoeurycea leprosa, to elucidate the timing and mechanisms of divergence in the Trans-Volcanic Belt of Mexico.

Location  The Trans-Volcanic Belt (TVB) of central Mexico, including the states of Mexico, Morelos, Puebla, Tlaxcala and Veracruz.

Methods  We sequenced the cytochrome b mitochondrial DNA gene for 281 individuals from 26 populations and nine mountain ranges in the TVB, and used Bayesian phylogenetic reconstruction and Markov chain Monte Carlo coalescent methods to infer historical demographic parameters and divergences among populations in each mountain system.

Results  We found deep genetic divergences between eastern and central TVB mountain systems despite their recent volcanic origin. Populations of P. leprosa show a pattern of refugial populations in the north-eastern and eastern limits of the species’ distribution, and genetic evidence of rapid population expansion in mountain ranges of the central TVB. The oldest divergences among populations date to c. 3.8 Ma, and the most recent divergences in the central TVB are Pleistocene in age (c. 0.7 Ma).

Main conclusions  Given the timing and order of population diversification in P. leprosa, we conclude that early isolation in multiple habitat refuges in north-eastern and eastern mountain ranges played an important role in structuring population diversity in the TVB, followed by population expansion and genetic divergence of the central range populations. The dynamic climatic and volcanic changes in this landscape generally coincide with the history of intra-specific diversification in P. leprosa. Climate-driven changes in habitat distribution in an actively changing volcanic landscape have shaped divergences in the TVB and very likely contributed to the high levels of speciation and endemism in this biodiverse region.

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