I study evolutionary diversification in the broad sense. My interests range from the role of ecological interactions in the speciation process to factors that determine the fates of clades over epochal timescales. My research incorporates fieldwork, molecular phylogenetics, and mathematical and computer modeling.
Australian skink diversification: I am studying ecological and lineage diversification in the Australian skink genus Ctenotus. With approximately 100 described species, Ctenotus is one of the most diverse genera of terrestrial vertebrates. Ctenotus species are found in virtually all habitats on the Australian mainland and dominate the lizard fauna of the arid interior – no mean feat, considering that Australia’s deserts may harbor the most diverse lizard communities on the planet! We have shown that Ctenotus – along with its sister genus Lerista – is characterized by exceptionally high rates of diversification relative to other lineages of Australian skinks. Many fascinating questions remain. Why have these groups experienced such explosive diversification? What are the relative roles of geographic isolation and ecological interactions in Ctenotus speciation? What are the links between the aridification of Australia and diversification in Ctenotus and other groups?
Ctenotus skinks from arid Australia. Top: C. schomburgkii;
bottom: C. pantherinus
Evolutionary radiations: Some groups of organisms have tremendous numbers of species,yet many more groups have only a few species. Likewise, some groups are much more 
ecologically diverse than others. These patterns are ubiquitous across the spectrum of biological diversity, yet their causal basis remains poorly understood. My work in this area involves both comparative analyses of diversification as well as the development of analytical tools for hypothesis testing. A sampling of questions I’m working on at the moment: what extrinsic and intrinsic factors influence differential rates of speciation and extinction among lineages? Do speciation rates during evolutionary radiations show density dependence, and how can we detect it? How can we combine inferences from molecular phylogenies and the fossil record to understand the dynamics of speciation and extinction through time? What are the roles of adaptive and non-adaptive processes in phenotypic and lineage diversification during major evolutionary radiations?
ecologically diverse than others. These patterns are ubiquitous across the spectrum of biological diversity, yet their causal basis remains poorly understood. My work in this area involves both comparative analyses of diversification as well as the development of analytical tools for hypothesis testing. A sampling of questions I’m working on at the moment: what extrinsic and intrinsic factors influence differential rates of speciation and extinction among lineages? Do speciation rates during evolutionary radiations show density dependence, and how can we detect it? How can we combine inferences from molecular phylogenies and the fossil record to understand the dynamics of speciation and extinction through time? What are the roles of adaptive and non-adaptive processes in phenotypic and lineage diversification during major evolutionary radiations?Systematics and diversity of squamate reptiles: Our molecular phylogenetic work on Ctenotus skinks has surprising taxonomic implications. In collaboration with researchers at several Australian institutions, we are working on formal taxonomic revision of a number of species complexes. My M.S. work focused on the systematics of Australian blindsnakes (Typhlopidae), and I maintain a general interest in the systematics, biodiversity, and biogeography of squamate reptiles.
