Phylogeography of two polytypic bird species from the Philippines

The Philippine archipelago exhibits one of the highest rates of faunal endemism in the world. In birds, half of the island group’s resident species are endemic. Yet given the high rate of endemism, diversity is still believed to be underestimated because of outdated taxonomy. In this study, we examine phylogeographic structure in two polytypic Philippine-endemic bird species: the Balicassiao (Dicrurus balicassius) and the Philippine Coucal (Centropus viridis). We assembled a dataset of DNA sequences from five mitochondrial and nuclear markers obtained from frozen tissue and toe pad samples from all three subspecies of D. balicassius and all four subspecies of C. viridis, as well as closely-related species as outgroups. We constructed phylograms using Bayesian and maximum likelihood phylogenetic inference methods. This study attempts to investigate whether genetic structure in populations of these two species coincide with phenotypic breaks. Preliminary results show paraphyly of Dicrurus balicassius and the genetic distinctiveness of two Philippine Dicrurus subspecies:  Dicrurus balicassius mirabilis and Dicrurus hottentottus palawanensis.  Our research provides evidence for elevating these two taxa to full species rank. Our results provide the basis for an updated taxonomic treatment of these two groups and yield insights on the biogeographic history of the archipelago.  This study highlights the need for re-assessment of Philippine bird taxonomy and re-evaluation of conservation priorities and efforts in the archipelago to account for these otherwise neglected taxa.