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Doctoral Research As a doctoral student in the Department of Zoology (now Integrative Biology) at the University of Texas at Austin, I was interested in the origin and evolution of Australia's rich lizard diversity. All five lizard families that presently exist in Australia including the varanids, agamids, skinks, geckos, and pygopodids contain clades that have undergone adaptive radiations in Australia. From a global perspective, the lizard species richness in contemporary Australia whether viewed at the continental or ecosystem level is staggering. For my dissertation research I used the lizard family Pygopodidae as a model clade from which to elucidate the timing, tempo, and cause of these spectacular radiations. 
Pygopodids are an enigmatic group of limb-reduced and elongate lizards (see photo of Delma fraseri left) that are most closely related to geckos. The group, which currently contains at least 36 extant species, is endemic to Australia and New Guinea. In collaboration with my doctoral advisor
Dr. Eric Pianka
and
Dr. Stephen Donnellan
of the South Australian Museum, we gathered a molecular dataset consisting of mitochondrial and nuclear gene sequences for nearly every described pygopodid species and representing all genera. Using state-of-the-art phylogenetic methods, we reconstructed the evolutionary relationships among the extant lineages. We then used the phylogeny to conduct further biogeographic analyses to help us understand the evolutionary history of this group. This study was later published in Systematic Biology (PDF).Postdoctoral Research My Postdoctoral research began in the Department of Zoology (now Biology) at the University of Washington and continued in the Department of Organismic and Evolutionary Biology at Harvard University. In collaboration with my postdoc advisor Dr. Scott Edwards  I spearheaded a study on the comparative phylogeography and historical demography of Australian songbirds in relation to geographic barriers located in northern Australia. Previous studies had pointed out that a number of different avian sister-species pairs are co-distributed across the Carpentarian Barrier in Queensland. We chose to examine one of these groups, the Australian Grass Finches (see Long-tailed Finch photo to right), as a model system from which to infer the importance of this biogeographic barrier. In our study, we employed new genomic-based methods along with recently developed coalescent maximum likelihood and Bayesian statistical programs to infer population genetic parameters such as historical effective population sizes, speciation times, and the species tree. We then used this gene-tree based information to help us better understand the importance of geological barriers to Australian bird diversification. This work was published in the journal Evolution (PDF).
Research at Humboldt State University Here in the Department of Biology at Humboldt State University, I maintain an active externally funded research lab where undergraduate and graduate students and I continue to investigate the evolutionary genomics and conservation genetics of vertebrates with an emphasis on birds, lizards, and amphibians. Our present geographic focus is Australia and California. If you are interested in joining our lab please see the "Prospective Students" page for more information. Web site design by Andrew Gottscho |
