Biogeography and evolutionary history of the Neotropical genus Saltator (Aves: Thraupini)
We reconstructed the biogeographical and evolutionary history of Saltator by producing a robust phylogenetic hypothesis that we used to evaluate the geographical origins of this genus, and assessed the potential influence of major Neotropical biogeographical features on the origin of lineages within this assemblage (i.e. phylogroups).
Our phylogenetic reconstruction is based on newly sequenced mitochondrial DNA data representing all known species of Saltator. This phylogenetic hypothesis was then used to define phylogenetic structure and to assess divergence times for these clades. Phylogroups were assigned to unique biogeographical regions allowing us (1) to perform ancestral biogeographical analyses (using rasp) to reconstruct ancestral areas for all nodes within our topology, and (2) to examine the geography of speciation and evolutionary history of Saltator.
The novel phylogenetic relationships in Saltator showed that this tanager clade originated and diversified in South America in the mid-Miocene (c. 13 Ma), ultimately yielding three distinct clades composed of a minimum of 26 phylogroups. A positive correlation was found between phylogenetic distance and co-occurrence (percentage range overlap) for Saltator.
Our evolutionary scenario for Saltator is consistent with a radiation initiated by uplift of the Andes during the last 10 million years. The biogeography of Saltator and the large number of phylogroups recovered suggest that an allopatric mode of speciation is the major driver in the evolutionary history of this group of tanagers.