The ground-doves of the Indo-Pacific have now been found to consist of two distinct lineages.
The genus Gallicolumba contains of 16 extant, two probably extinct and six extinct species of ground-doves, found in the Indo-Pacific region, representing a prime example of the influence of insular isolation on radiation from a common ancestor.
Ground-doves come in two distinct plumage forms: the bleeding-hearts which have an yellow, orange or red breast patch and pale underparts from the Philippine archipelago, and the brown ground-doves, which have a bronze sheen and occur on Pacific islands and New Guinea. It has been suggested by previous authors that the latter may be closer to the Australasian doves of the genera Geopelia, Phaps and Leucosarcia.
Performing a phylogenetic analysis using three gene segments from fresh tissue and museum specimens, a team has managed to sequence 20 Gallicolumba species plus representatives of the other genera (including Ocyphaps and Geophaps, too) with Zenaida and Hemiphaga as outgroups (more distantly-related forms used to 'root' the resulting evolutionary tree).
Their results showed that the bleeding-hearts were indeed widely divergent from the other ground-doves, indicating that the genus Gallicolumba does not consist of all the descendants of one common ancestor, and should thus be split. The bleeding-hearts have priority on the genus Gallicolumba, and so the team propose the resurrection of the genus Alopecoenas for the more recently-evolved Pacific Island and New Guinean forms. They also note that the New Guinean Cinnamon Ground-dove also belongs with the bleeding-hearts, which can be further split into two clades.
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Bronze Ground-dove, Solomon Islands. Photo: Michael Køie Poulsen. |
The close relationship between the true Alopecoenas ground-doves and the various genera of Australasian genera - often viewed as 'oversplit' themselves - probably indicates an Australo-Papuan origin, in line with many other regionally endemic groups. Their phylogeny also indicates that Australia's Wonga Pigeon is part of the same clade, supporting this origin. Despite the lack of records of ground-doves crossing water they appear to have rapidly spread and radiated far into the Pacific, with Bronze Ground-dove even having spread to the Bismarck archipelago as late as the 19th century.
Reference: Jønsson, K A, Irestedt, M, Bowie, R C K, Christidis, L and Fjeldså, J. 2011. Systematics and Biogeography of Indo-pacific ground-doves. Molecular Phylogenetics and Evolution. doi:10.1016/j.ympev.2011.01.007
Acknowledgement
Thanks to corresponding author Knud Jønsson for his help with this item.
