Phylogenetics of Marmotine Ground Squirrels
Using both traditional and genomic datasets, I am interested in reconstructing the phylogeny of members of the tribe Marmotini (chipmunks, ground squirrels, prairie dogs, marmots). This Holarctic group of ~91 species has radiated into a variety of body sizes and ecologies and is thus an ideal system for understanding diversification dynamics in a temperate rodent group. This work is occurring at 2 different levels:
The history of high-latitude adaptation in Urocitellus
Holarctic ground squirrels (Urocitellus, 12 species) have been the subject of a range of ecological, physiological and life history research over the past 4 decades. I am using both traditional multilocus and genomic approaches to infer phylogeny, delimit species boundaries and identify instances of ancient hybridization in this genus. This will also provide a comparative basis for assessing timing and sequence of Arctic colonization, as well as understanding various morphological and physiological adaptations to high latitude.
Species trees of Urocitellus (plus 2 outgroups) reconstructed using 3 different methods. Dataset includes 6 loci.
Phylogeny and the timescale of diversification in Marmotini
Collaborators and I are working to resolve the phylogeny of all marmotine ground squirrels using ultraconserved elements, and to robustly date this tree using a newly expanded suite of fossil calibrations and Bayesian calibration methods. We are particularly interested in understanding the timing of diversification in reference to Neogene climate warming and environmental change.