Research in the Rabosky Lab
The ecology of macroevolution in Australian squamate reptiles
We study evolutionary radiations of squamate reptiles from arid Australia to understand feedbacks between ecological community processes and diversification. Arid Australia contains some of the most species-rich terrestrial vertebrate communities known and provides a series of replicated natural experiments, where multiple clades of trophically-similar organisms have diversified against a common ecological and biogeographic background. We use this system to assess the importance of niche conservatism, species interactions, and environmental filtering in generating species assemblages across a hierarchy of spatial scales, and to explore how these interactions influence broad scale patterns of speciation, extinction, and trait evolution.
Species and phenotype diversification across the tree of life
Understanding the general processes that underlie large-scale evolutionary trends and diversity patterns requires synthesizing patterns across many types of evolutionary radiations. We test hypotheses to explain why some kinds of organisms have such exceptional species and phenotypic diversity by combining phylogenetic, ecological, and paleontological information for groups drawn broadly from the tree of life (e.g., angiosperms, marine phytoplankton, anolis lizards, arthropods).
Much of this work involves developing new statistical models and analytical techniques. A sampling of questions we are 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 diversity 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 equilibrium and non-equilibrium processes in shaping species richness across the tree of life?
Biodiversity and biogeography of squamate reptiles
We use molecular phylogenetic and phylogeographic approaches to understand species richness and biogeography in Australian lizards, particularly skinks in the genus Ctenotus. With approximately 100 described species, Ctenotus is one of the most diverse genera of terrestrial vertebrates. Our phylogenetic work on Ctenotus has surprising taxonomic implications, and we are collaborating with researchers at several Australian institutions to formally revise a number of species complexes. This work also provides an exciting window into the historical processes that drive speciation and influence population structure in the hyper-diverse deserts of interior Australia.