Monday, December 4, 2017

[Ornithology • 2018] Recovering the Evolutionary History of Crowned Pigeons (Columbidae: Goura): implications for the Biogeography and Conservation of New Guinean Lowland Birds


Goura cristata 

Bruxaux, Gabrielli, Ashari, et al. 2018

Highlights
• A phylogenetic analysis of crowned pigeons (Goura) is presented.
• Mitochondrial and nuclear DNA analyses resolved Goura into 4 monophyletic groups.
• Species formerly considered as subspecies are not each other's closest relatives.
• Dating suggests diversification of Goura within New Guinea since the Late Miocene.
• The biogeographic origin of the Goura lineage remains elusive.

Abstract
Assessing the relative contributions of immigration and diversification into the buildup of species diversity is key to understanding the role of historical processes in driving biogeographical and diversification patterns in species-rich regions. Here, we investigated how colonization, in situ speciation, and extinction history may have generated the present-day distribution and diversity of Goura crowned pigeons (Columbidae), a group of large forest-dwelling pigeons comprising four recognized species that are all endemic to New Guinea. We used a comprehensive geographical and taxonomic sampling based mostly on historical museum samples, and shallow shotgun sequencing, to generate complete mitogenomes, nuclear ribosomal clusters and independent nuclear conserved DNA elements. We used these datasets independently to reconstruct molecular phylogenies. Divergence time estimates were obtained using mitochondrial data only. All analyses revealed similar genetic divisions within the genus Goura and recovered as monophyletic groups the four species currently recognized, providing support for recent taxonomic changes based on differences in plumage characters. These four species are grouped into two pairs of strongly supported sister species, which were previously not recognized as close relatives: Goura sclaterii with Goura cristata, and Goura victoria with Goura scheepmakeri. While the geographical origin of the Goura lineage remains elusive, the crown age of 5.73 Ma is consistent with present-day species diversity being the result of a recent diversification within New Guinea. Although the orogeny of New Guinea's central cordillera must have played a role in driving diversification in Goura, cross-barrier dispersal seems more likely than vicariance to explain the speciation events having led to the four current species. Our results also have important conservation implications. Future assessments of the conservation status of Goura species should consider threat levels following the taxonomic revision proposed by del Hoyo and Collar (HBW and BirdLife International illustrated checklist of the birds of the world 1: non-passerines, 2014), which we show to be fully supported by genomic data. In particular, distinguishing G. sclaterii from G. scheepmakeri seems to be particularly relevant.

Keywords: New Guinea; Goura; Crowned pigeons; Molecular phylogeny; Biogeography





Jade Bruxaux, Maëva Gabrielli, Hidayat Ashari, Robert Prŷs-Jones, Leo Joseph, Borja Milá, Guillaume Besnard and Christophe Thébaud. 2018. Recovering the Evolutionary History of Crowned Pigeons (Columbidae: Goura): implications for the Biogeography and Conservation of New Guinean Lowland Birds. Molecular Phylogenetics and Evolution. In Press.  DOI:  10.1016/j.ympev.2017.11.022

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