Biogeography of the Andean metaltail hummingbirds: contrasting evolutionary histories of tree line and habitat‐generalist clades. (24th December 2014)

• Record Type: Journal Article
• Authors: Benham, Phred M.; Cuervo, Andrés M.; McGuire, Jimmy A.; Witt, Christopher C.; Patten, Michael
• Is Part Of: Journal of biogeography. Volume 42:Number 4(2015:Apr.)
• Page Start: 763
• Page End: 777
• Publication Date: 2014-12-24
• Subjects: Biogeography -- Periodicals; 578.09
• DOI: 10.1111/jbi.12452
• Languages: English
• ISSNs: 0305-0270

Abstract

<abstract abstract-type="main" id="jbi12452-abs-0001"> <title>Abstract</title> <sec id="jbi12452-sec-0001" sec-type="section"> <title>Aim</title> <p>To assess geographical and temporal patterns of diversification in <italic>Metallura</italic> hummingbirds, particularly with respect to topographical barriers and climatic variation between different populations.</p> </sec> <sec id="jbi12452-sec-0002" sec-type="section"> <title>Location</title> <p>Tropical Andes.</p> </sec> <sec id="jbi12452-sec-0003" sec-type="section"> <title>Methods</title> <p>We estimated a multilocus phylogeny for all nine species of <italic>Metallura</italic> and evaluated phylogeographical patterns within <italic>Metallura tyrianthina</italic> using mitochondrial DNA sequences from across its range (<italic>n</italic> = 192). We tested mechanisms of diversification using climatic classification of sampling sites, coalescent‐based dating, lineages‐through‐time plots and dispersal–vicariance analysis.</p> </sec> <sec id="jbi12452-sec-0004" sec-type="section"> <title>Results</title> <p> <italic>Metallura</italic> consists of two main clades: (1) the tree line specialists in the <italic>M. aeneocauda</italic> superspecies; and (2) a habitat‐generalist clade that includes <italic>M. tyrianthina</italic> and <italic>M. iracunda. Metallura phoebe</italic> 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 <italic>Metallura</italic> hummingbirds through the Pliocene and the Pleistocene.</p> </sec> <sec id="jbi12452-sec-0005" sec-type="section"> <title>Main conclusions</title> <p>Isolation across topographical barriers best explained the genetic structure in <italic>M. tyrianthina</italic>. The two <italic>Metallura</italic> 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 <italic>Metallura</italic> and other Andean bird clades to undergo radical range shifts, including dispersal across topographical barriers, that became key to their diversification.</p> </sec> </abstract>