The Steppan Lab
Scott J. Steppan
My fundamental goal is to understand the evolutionary processes that promote biological diversity. My research attempts to bridge the micro- and macroevolutionary scales and apply process based models to understand and explain large-scale patterns. To address this long term goal, my research program involves studying highly diversified groups of mammals at a range of hierarchical levels. Currently, my focus is on molecular phylogenetics and quantitative genetics. The techniques include phylogenetic analyses of morphological and DNA sequence data, comparative analyses of multivariate patterns of covariation, developing the comparative tools to test these multivariate patterns, analysis of geographic variation, and alpha level systematics of living and fossil material.

Graduate Students

Lisa Barrow (co-advised by Emily Lemmon):

John Schenk My research aim is to uncover the evolutionary processes that have led to the present diversity in the muroid rodent clade. Twenty-eight percent of the species diversity found in the mammalian lineage are rodents, and much of this diversity is represented by muroids (Old World mice and rats, voles, gerbils, sigmodontines, etc.). We use statistical phylogenetic approaches to examine putative evolutionary processes that have led to its diversity, such as ecological opportunity and key innovations.
Nathanael Herrera I am a Masters student interested in macroevolution, biogeography, morphological evolution, and phylogentetics. Currently, I am addressing these types of questions using bivalves from the family Cardiidae (cockles and giant clams) as my study system.

Kenny Wray I am interested in the fuzzy boundary between microevolution and macroevolution. Specifically, I am interested in the mechanisms and processes involved in speciation. I use a variety of phylogenetic and phylogeographic techniques to undesrtand these processes using a diverse array of data sets (mtDNA, nuclear DNA, morphology, etc.). I also apply these techniques to principles in conservation biology with the goal of assisting agencies in effectively managing species/unique populations for the future.

Currently, I am exploring questions of speciation in the Dwarf Salamander (Eurycea quadridigitata) complex, as well as issues of habitat restoration and conservation management of the Federally threatened Flatwoods Salamander (Ambystoma cingulatum).

Bárbara Maria de Andrade Costa (Universidade Federal do Sao Paulo, Brazil, co-advised by Gabriel Marroig): I am broadly interested in Neotropical mammal diversification processes (mainly small mammals), their systematics, and phylogeography. My Ph.D. work focuses on morphological integration analysis of the Sigmodontinae rodents - a Neotropical monophyletic group that comprises one of the greatest recent mammal radiations. My research uses geometric morphometric techniques of skull in a developing Sigmodontinae molecular phylogeny to explore multivariate morphological evolution (especially P-matrix evolution) in this clade.
Bader Alhajeri I am working on uncovering the morphological and ecological correlates of diversity (adaptive radiations) in Muroids using phylogenetic comparative methods. I also plan to work on the ecological correlates of shape variation in Muroids, with the focus being on the ecological adaptations to deserts.
Rebecca Justiniano I am focusing on the diversification of the genus Apomys that is endemic to the Philippines. I am currently generating molecular data from nuclear and mitochondrial genes in order to construct a phylogenetic tree to hypothesize the relationships among new species of Apomys.
Bekhi Falter I am an undergraduate in Biological Science. I began research on the South American rodent group Sigmodontinae in the Steppan lab during summer 2010 as an REU (Research Experiences for Undergraduates, a National Science Foundation Grant) student. My current project is estimating the Rodent SuperTree, which uses published studies to reconstruct a graphical representation of the evolutionary relationships between all extant rodent groups. The Rodent SuperTree will provide a more comprehensive understanding of the evolution of Rodentia.
Amanda Libert I am an undergraduate in biological science. I currently work on two projects in the lab. The first involves using molecular techniques to determine the phylogeny of genus Phyllotis, the leaf-eared mice of South America. The second involves using similar techniques to determine the evolution of the Lynx genus of cats in Europe and North America.

Anna Meyer I am an undergraduate Biological Science major. I am interested in evolution and evolutionary genetics, and hope to one day work on human evolution. Currently, I am gathering molecular data to create and analyze the phylogeny of genus Phyllotis, a group of South American mice. Analysis of these data will help answer questions about speciation across varying elevations, as the members of Phyllotis live at a variety of altitudes along the Andes Mountains.
Past Members