Wednesday, 14 March 2012

Phylogeny of Pacific pigeons

Orange dove, Ptilinopus victor
Orange dove Ptilinopus victor. Picture courtesy of aviceda on Flickr

In the avifauna of the Pacific, pigeons rule. Considering the region as a whole, pigeons are one of the most widespread and speciose groups of birds in the area. In particular, the imperial pigeons (Genus Ducula) and the fruit doves (Genus Ptilinopus) are especially widespread, being found from South-east Asia to French Polynesia, and with most major islands having at least one endemic species. Despite this diversity however, South Pacific pigeons have tended to not be included in analyses of pigeon evolution as a whole.

To rectify this, Gillian Gibb and David Penny present a phylogeny estimated from a number of mitochondrial genes that includes 9 species of imperial pigeon, and 13 species of fruit dove (including the orange dove Ptilinopus victor shown above), along with representatives of a number of other pigeon genera. Australasia and Oceania have the bulk of the representation in this analysis—of the 25 genera represented, only 10 have no species in the region.

They found that the imperial pigeons are monophyletic (that is, they form a natural grouping) and are rather distinct from the remainder of the pigeons sampled. The fruit doves on the other hand are prevented from forming a natural clade by the presence of the cloven-feathered dove (Drepanoptila holosericea) of New Caledonia, and the blue dove (Alectroenas madagascariensis) of (you guessed it...) Madagascar. When you look at pictures of these two, it's not surprising that they might be fairly close to Ptilinopus. What is surprising though, is that these two species are resolved as being sister taxa, despite being so geographically distant from each other. This puzzle obviously requires rather more investigation.

Gibb GC, Penny D. (2010). Two aspects along the continuum of pigeon evolution: A South-Pacific radiation and the relationships of pigeons within Neoaves. Molecular Phylogenetics and Evolution 56: 698–706

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