Abstract of an article which appeared in ‘The Auk’ Vol 116, No4, August 1999

Molecular Systematics and Biogeography of the Cockatoos (Psittaciformes: Cacatuidae)

by David M. Brown and Catherine A. Toft

We sequenced a 433-bp region of the mitochondrial 12S ribosomal subunit gene for 15 of the 18 recognized species of cockatoos and also examined previously published data on allozymes.

Tests showed that the allozyme and mtDNA data have similar phylogenetic signals. The mtDNA phylogeny placed the Palm Cockatoo (Probosciger aterrimus) as the first extant cockatoo to split, followed by a subclade containing the black-cockatoos (Calyptorhynchus spp.), the Cockatiel (Nymphicus hollandicus), and the Gang-gang Cockatoo (Callocephalon fimbriatum); followed by the Galah (Eolophus roseicapillus) and Major Mitchell's Cockatoo (Cacatua leadbeateri), respectively; and finally followed by two subclades of "white" cockatoos : (1) the "corella" clade (Red-vented Cockatoo [Cacatua haematuropygia], Goffin's Cockatoo [C. goffini], Little Corella [C. sanguinea], Ducorps's Cockatoo [C. ducorpsii]); and (2) the "galerita" clade (Sulphur-crested Cockatoo [C. galerita], Salmon-crested Cockatoo [C. moluccensis], White Cockatoo [C. alba], Blue-eyed Cockatoo [C. ophthalmica], and Lesser Sulphur-crested Cockatoo [C. sulphurea]).

If the mtDNA phylogeny accurately represents the evolutionary history of the cockatoos, then several of the phylogenetic problems within the group are resolved, including the positions and relationships of Nymphicus hollandicus, Callocephalon fimbriatum, Eolophus roseicapillus, and Cacatua leadbeateri.

The mtDNA phylogeny supports some but not all of the nomenclature recently proposed for the Australian species. Biogeographic analysis of the mtDNA phylogeny supports the hypothesis that the cockatoos originated in Australia and that a combination of vicariant speciation and dispersal may have contributed to the diversification of the genus Cacatua in two separate radiations to the island regions of Indonesia, New Guinea, and the South Pacific.

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