Origin and diversification of Philippine bulbuls

Abstract

We examine the origin and diversification of Philippine bulbuls using a phylogenetic framework. We used maximum likelihood and Bayesian methods to construct trees from DNA sequences of two mitochondrial and two nuclear genes obtained from 11 Philippine bulbul species as well as 32 other Asian and African taxa. We found eight independent colonization events of bulbuls to the Philippines, including one clade comprising Philippine members of the genus Ixos that underwent extensive diversification within the archipelago. Each Philippine clade of bulbuls invaded either the Palawan region or the oceanic islands of the Philippines, but not both. Genetic data reveal at least 5 lineages that warrant recognition as full species. This study underscores how Philippine avian diversity is currently underestimated and highlights the need for further phylogenetic studies in other Philippine bird groups.