The influence of the complex topography and dynamic history of the montane Neotropics on the evolutionary differentiation of a cloud forest bird ( Premnoplex brunnescens , Furnariidae)

Abstract

Aim To examine the effect of geographical barriers and habitat dynamics related to climatic oscillations on the phylogeography of a widespread passerine of Neotropical cloud forests, the spotted barbtail ( Premnoplex brunnescens ). Location Neotropical humid forests of montane areas in lower Central America and South America. Methods We sequenced two mitochondrial genes and one nuclear intron from specimens collected across the distribution of P. brunnescens . Phylogenetic relationships were inferred using Bayesian and maximum‐likelihood methods. Groups with maximum differentiation were estimated with spatial analysis of molecular variance ( SAMOVA ). We estimated timing of differentiation and relationships among groups with a species‐tree approach and historical demography with extended Bayesian skyline plots. Results Six highly differentiated clades of P. brunnescens are distributed in lower Central America, Sierra Nevada de Santa Marta, northern Venezuelan mountains, the Northern Andes, central Peru, and southern Peru and Bolivia. Within the Northern Andes clade, six phylogroups were identified associated with different slopes and isolated cordilleras. Most clades occupy opposite sides of low‐lying valleys and ridgelines, but little differentiation was observed across several putative barriers. Population divergence occurred in the late Miocene and Pliocene, perhaps in association with Andean uplift. Historical fluctuations in population sizes suggest that populations tracked the spatial dynamics of montane forests associated with glacial cycles. Main conclusions Extensive genetic differentiation in mitochondrial and nuclear DNA exists among populations of P. brunnescens . Such marked divergence was probably promoted by the rugged topography and dynamic ecological history of the Neotropical mountains. Our study sheds light on mechanisms promoting population differentiation in the montane Neotropics.

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