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Biogeography of the Andean metaltail hummingbirds: contrasting evolutionary histories of tree line and habitat‐generalist clades
Author(s) -
Benham Phred M.,
Cuervo Andrés M.,
McGuire Jimmy A.,
Witt Christopher C.
Publication year - 2015
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.12452
Subject(s) - vicariance , clade , generalist and specialist species , biogeography , biology , phylogeography , ecology , biological dispersal , parapatric speciation , molecular clock , coalescent theory , habitat , phylogenetics , genetic variation , gene flow , population , biochemistry , sociology , gene , demography
Aim To assess geographical and temporal patterns of diversification in Metallura hummingbirds, particularly with respect to topographical barriers and climatic variation between different populations. Location Tropical Andes. Methods We estimated a multilocus phylogeny for all nine species of Metallura and evaluated phylogeographical patterns within Metallura tyrianthina using mitochondrial DNA sequences from across its range ( n = 192). We tested mechanisms of diversification using climatic classification of sampling sites, coalescent‐based dating, lineages‐through‐time plots and dispersal–vicariance analysis. Results Metallura consists of two main clades: (1) the tree line specialists in the M. aeneocauda superspecies; and (2) a habitat‐generalist clade that includes M. tyrianthina and M. iracunda. Metallura phoebe was recovered as sister to the tree line clade in some analyses. In both clades, there was marked genetic structure across topographical barriers and almost no structure between climatically distinct regions in the absence of barriers. The tree line clade exhibited deeper divergences in the Central Andes than elsewhere, and a south‐to‐north history of diversification, whereas the habitat‐generalist clade showed deeper divergences in the Northern Andes and a history of southward expansion. A pure‐birth model explained the steady net rate of diversification of Metallura hummingbirds through the Pliocene and the Pleistocene. Main conclusions Isolation across topographical barriers best explained the genetic structure in M. tyrianthina . The two Metallura clades expanded from opposite ends of the Andes, leading to asynchronous divergence across common topographical barriers. Cycles of expansion followed by isolation may explain the preponderance of idiosyncratic area relationships that are typical of Andean clades. Geoclimatic dynamism during the Pleistocene caused Metallura and other Andean bird clades to undergo radical range shifts, including dispersal across topographical barriers, that became key to their diversification.