Evolution in Australasian Mangrove Forests: Multilocus Phylogenetic Analysis of the Gerygone Warblers (Aves: Acanthizidae)

Árpád S Nyári,Leo Joseph,Robert C Fleischer

doi:10.1371/journal.pone.0031840

Abstract

The mangrove forests of Australasia have many endemic bird species but their evolution and radiation in those habitats has been little studied. One genus with several mangrove specialist species is Gerygone (Passeriformes: Acanthizidae). The phylogeny of the Acanthizidae is reasonably well understood but limited taxon sampling for Gerygone has constrained understanding of its evolution and historical biogeography in mangroves. Here we report on a phylogenetic analysis of Gerygone based on comprehensive taxon sampling and a multilocus dataset of thirteen loci spread across the avian genome (eleven nuclear and two mitochondrial loci). Since Gerygone includes three species restricted to Australia's coastal mangrove forests, we particularly sought to understand the biogeography of their evolution in that ecosystem. Analyses of individual loci, as well as of a concatenated dataset drawn from previous molecular studies indicates that the genus as currently defined is not monophyletic, and that the Grey Gerygone (G. cinerea) from New Guinea should be transferred to the genus Acanthiza. The multilocus approach has permitted the nuanced view of the group's evolution into mangrove ecosystems having occurred on multiple occasions, in three non-overlapping time frames, most likely first by the G. magnirostris lineage, and subsequently followed by those of G. tenebrosa and G. levigaster.

Highlights

Among the members of the primarily Australo-Papuan passerine family Acanthizidae, the genus Gerygone Gould, 1841 is the most geographically widespread
We did not attempt to reconcile the allelic phase of heterozygous base calls, but rather coded them as ambiguous according to the International Union of Pure and Applied Chemistry (IUPAC) standards
While multilocus phylogenetic analyses have been successfully employed throughout a diverse array of avian groups [13,42,43,44,45,46], the present study explored the utility of a moderate number of unlinked loci spread across the avian nuclear and mitochondrial genomes to better understand the implications of individual gene histories and their influence on species tree estimation. [17,20,21,47]

Summary

Introduction

Among the members of the primarily Australo-Papuan passerine family Acanthizidae, the genus Gerygone Gould, 1841 is the most geographically widespread. Habitats range from closed canopy moist forests to open arid zone woodlands, and at least three species (G. magnirostris, G. tenebrosa, G. levigaster) occur predominantly in coastal mangrove forests, and another, G. chloronota, enters them in Australia as well [1,2,3]. Given their diverse biogeographic and ecological patterns, gerygones are among the groups best-suited for elucidating the origin of Australia’s rich mangrove avifauna [2,3,4,5]. They are an ideal group with which to apply molecular phylogenetics to the testing of hypotheses that have been advanced for evolution of mangrove specialist birds in the region [2,3,4,5]

Methods

Results

Conclusion