A robust phylogeny of the oropendolas: Polyphyly revealed by mitochondrial sequence data

We present a robust, fully resolved phylogeny for the oropendolas that will serve as a basis for comparative studies in this group. We sequenced 2,011 base pairs (bp) of the mitochondrial cytochrome-b and ND2 genes from 22 individuals to reconstruct relationships between recognized species and subspecies and to assess variation within polytypic taxa. A single phylogenetic tree was produced despite the use of a wide range of weighting schemes and phylogenetic reconstruction methods. Our data provide strong evidence that oropendolas are polyphyletic, with two distinct groups within a larger clade of oropendolas and caciques. We confirm the monophyly of recognized species, but indicate that some within-species relationships do not conform to recognized subspecies limits. Our findings thus demonstrate the importance of including multiple exemplars from each taxon of interest. The two genes provided complimentary and equally effective phylogenetic information for comparisons within the oropendolas, but exhibited lower resolution in comparisons above the species level.