Luke Mahler, Graduate Student

Department of Organismic and Evolutionary Biology
& Museum of Comparative Zoology
Harvard University
26 Oxford Street
Cambridge, MA 02138
USA

Email: lmahler@oeb.harvard.edu
Phone: (617) 496-9099

I am interested in the evolution of phenotypic diversity in lizard clades, particularly in the role of ecological factors in regulating the diversification of organismal body form and life history. Questions driving my current research are:

Why do closely related clades exhibit differing patterns of phenotypic evolution (particularly morphological disparity) in different biogeographic or ecological contexts?

What is the relationship between phenotypic and phylogenetic diversity? Under what ecological circumstances does this relationship change? What is the role of history (time) in influencing this relationship? Do rates of phenotypic diversification change predictably with time?

Does phenotypic diversification occur differently in insular versus continental habitats? Do differences in community and ecosystem structure between these habitats translate to macroevolutionary differences in morphology and life history?

To address these questions, I use comparative methods to analyze patterns of macroevolutionary change in clades of lizards. I couple phylogenetic hypotheses for lizard groups of interest with measurements of morphological traits of interest to track trends in the evolution of lizard body form over time and space.

One project compares the evolution of Anolis lizards in insular and continental habitats. Anoles, which are renowned for their high taxonomic and phenotypic diversity, have undergone evolutionary radiations in both island and continental habitats in neotropical America. Anoles inhabiting the Greater Antilles in the Caribbean have diversified into discrete ecomorphs multiple times: on each of the four Greater Antilles (Cuba, Hispaniola, Jamaica, and Puerto Rico), anoles have converged upon similar life histories and morphologies, and exhibit a very diverse range of lifestyles and shapes. Has diversification occurred similarly among continental anoles? Currently I am investigating the evolution of morphological disparity and rates of morphological evolution in mainland and island anole clades. Comparisons are made at several hierarchical levels, ranging from whole-radiation to community-community comparisons.