08/02/2012
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An increase in racquet-tails

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This Blue-crowned Racquet-tail of the nominate subspecies, photographed at the PICOP plantation at Bislig, Surigao del Sur, Mindanao, The Philippines in February 20006, could well be a separate species from the other two forms. Photo: Benedict De Laender
This Blue-crowned Racquet-tail of the nominate subspecies, photographed at the PICOP plantation at Bislig, Surigao del Sur, Mindanao, The Philippines in February 20006, could well be a separate species from the other two forms. Photo: Benedict De Laender

The genetics of an endemic Wallacean parrot genus have revealed another potential species as well as their evolutionary history.


It has long been suspected that the Philippines (and Wallacea, the area of Indonesian islands separated from Asia and Australia by deep water trenches) hold much more biodiversity than has yet been described, and a new robust genetic analysis by Swiss researchers has shown that this is true in the racquet-tails Prioniturus, an endemic parrot group sharing distinctive paired elongated tail feathers with spoon-shaped tips.


The genus is usually considered to consist of nine species, but the new study suggests that the three subspecies of Blue-crowned Racquet-tail P discurus should also be discreet species, with P (d) mindorensis being a member of a different lineage to the other two, sister to Blue-headed Racquet-tail P platenae. The positions of the other two Blue-crowned Racquet-tail subspecies, nominate and whiteheadi, remain indeterminate and warrant further research, but it is thought very likely that they are separate species owing to morphological and genetic differences.

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The researchers uncovered three major clades: a Moluccan cade with Buru P mada and Golden-mantled P platurus Racquet-tails (including three closely-related subspecies sustained by this research); and two Philippino clades. Most existing species are supported, including the formerly contentious separation of Luzon Raqcquet-tail P montanus and Mindanao Racquet-tail P waterstradti; they aren't each others' closest relatives.


As far as origins were concerned, the genus was found to have originated from a single colonisation event from Australia around 20 million years ago. These were followed by five different dispersal events to various islands resulting in the current distribution of taxa. The Philippine-specific birds were also the result of a single colonisation, followed by speciation and further dispersal to Sulawesi, Palawan and Sulu.


Reference
Schweizer, M, Güntert, M and Hertwig, S T. 2012. Phylogeny and biogeography of the parrot genus Prioniturus (Aves: Psittaciformes). Journal of Zoological Systematics and Evolutionary Research. doi: 10.1111/j.1439-0469.2012.00654.x