The Eastern Hemisphere tropics, including Asia, Africa, and Madagascar, has a rich geological and biotic history. My work in these regions has expanded our knowledge of the species-limits, phylogenetic relationships, and biogeographic patterns of songbirds.
Madagascar
Madagascar is unique in having several avian endemic radiations. Vangas are a classic example of an adaptive radiation, yet many questions remain regarding the diversification of this group. In Reddy et al. (2012), we showed that this ecomorphologically diverse group is monophyletic and includes several disparate species that until recently were classified with other families. We demonstrated that vangas explosively speciated upon colonization of Madagascar with subsequent increases in diversification into novel niches.
Asia
The avifauna of southern Asia is one of the most diverse in the world, with tremendous species richness and endemism. Babblers form a major component of the tropical Asian avifauna and are an ideal group for examining patterns of diversification. Through detailed analysis of museum specimens and DNA data, I examine morphological, genetic, and geographic information to assess species-limits. My studies show that diversity of Asian birds is dramatically underestimated.
Avian tree of life
Funded by the NSF’s Assembling the Tree of Life program, our project collected over 32 kilobases of DNA sequences for each of more than 200 representative species across the diversity of modern birds. Hackett, Kimball, Reddy et al. (2008) reported a well-resolved phylogenetic tree of modern birds with many novel and highly-supported, deep relationships. Our analyses also show extremely short internodes at the base of modern birds, indicative of a rapid radiation. Birds exhibit considerable heterogeneity of evolutionary rates within and across lineages. The complexities of nearly simultaneous divergences combined with varying rates of evolution have contributed to the difficulty associated with resolving the phylogenetic history of birds using either genetic or morphological data. Subsequent studies from other labs have corroborated many of the novel relationships uncovered in our study.
Genomics and morphology of Antarctic penguins
Climate change poses a serious threat to penguins in Antarctica, and they will face changes to their habitat and prey availability in the near future. Our research on penguins uses genomics and morphometrics to understand how different species and populations of penguins are physically adapted to their environment and how those adaptations have changed throughout the history of the family. This research will lead to new insights into how constrained or adaptable different penguin traits are, and how species are likely to respond as their environment changes in the future.
