Niche divergence promotes rapid diversification of East African sky island white-eyes (Aves: Zosteropidae).
Bottom Line: To explain their elevated diversity within this region, models founded on niche conservatism have been offered, although detailed phylogeographic studies are limited to a few avian lineages.Our results also highlight an underestimation of diversity compared to morphological studies that has implications for their taxonomy and conservation.Molecular dating suggests that the spatially extensive African radiation arose exceptionally rapidly (1-2.5 Ma) during the fluctuating Plio-Pleistocene climate, which may have provided the primary driver for lineage diversification.
Affiliation: Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK; Bird Group, Department of Life Sciences, The Natural History Museum, Akeman Street, Tring, Hertfordshire, HP23 6AP, UK.Show MeSH
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Mentions: Bayesian inference of the AFLP data identified the two Z. borbonicus subspecies (Ancient Indian Ocean, AIO) as sister to all Africa taxa (BPP = 1.00, Fig.4), which is concordant with the mtDNA phylogeny. However, there is no support for the broader clades (A and B) recovered in the mtDNA phylogeny. Despite the lack of power in the AFLP data to resolve interrelationships, there is good support for the monophyly of range-restricted taxa of continental montane forests (i.e. Z. poliogastrus subspecies). Conversely, there is very little support for the monophyly of subspecies and/or populations of more widely distributed taxa such as Z. abyssinicus and Z. senegalensis. Leaf stability (Thorley & Wilkinson 1999), implemented in the program Phyutility (Smith & Dunn 2008), was used to assess if the lack of resolution in the initial data (92 taxa) was caused by unstable or rogue taxa. On the basis of leaf stability scores, 14 taxa were discarded, and while the resulting analysis of the reduced matrix resulted in a slightly more resolved hypothesis indicating the nonmonophyly of Z. poliogastrus, this result was only weakly supported. Taxon reduction made little impact in resolving deeper level relationships or subspecies monophyly of wide ranging taxa.
Affiliation: Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK; Bird Group, Department of Life Sciences, The Natural History Museum, Akeman Street, Tring, Hertfordshire, HP23 6AP, UK.