Meeting Abstract

28.7  Jan. 5  Evolution of gibbons: resolving the Hylobates phylogeny with multiple datasets WHITTAKER, D.J.; Indiana University, Bloomington djwhitta@indiana.edu

The lar group of gibbons or small apes (genus Hylobates) has long represented a phylogenetic puzzle, with different datasets producing very different results. Most likely, this radiation represents a true polytomy. Rising sea levels in southeast Asia during the Pleistocene simultaneously isolated populations of gibbons which subsequently diverged into the six species present today. Nonetheless, molecular and vocal data have indicated variation in the degree of divergence among the species and a comparison of datasets reveals a biogeographic pattern. As the more slowly evolving genes typically used for phylogenetic analysis proved uninformative for this genus, I sequenced the hypervariable region I (HV-I) of the mitochondrial control region, or D-loop, and constructed a phylogenetic tree of the lar group. I then compared this phylogeny to published datasets (the ND3-4 locus, vocalizations, and morphological traits) by testing for congruence. The Kloss�s gibbon (H. klossii), which was long considered a primitive representative of the genus based on morphological characteristics, shares many molecular and vocal characteristics with the Javan gibbon (H. moloch), and these two taxa, along with the agile gibbon (H. agilis) appear to be the most recently derived species. Meanwhile, the northernmost species (H. lar and H. pileatus) appear at the base of the radiation. No significant incongruence was found between the D-loop data and the other datasets. Together these data suggest that ancestral gibbons radiated from north to south. They also have important implications for understanding the evolution of other species in the region. Unlike the other markers, the HV-I region can accurately identify members of different gibbon species much like a DNA barcode, which should have applications in conservation efforts.