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| Current Research | Publications | Contact | Photography |
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.
Molecular systematics of muroid rodents
Phylogeography and specieation in Andean Phyllotis using multiple loci
Comparative analysis of covariance structure
Molecular phylogenetics of marmots and squirrels (Sciuridae)
Systematics of sigmodontine mice: DNA sequencing, Morphology, Paleontology, Biogeography
Constraints on the evolution of the vertebral column in rodents.
Jill Holliday: evolution of hypercarnivory in living and extinct carnivorans, especially cats.
Kenny Wray: phylogeography and evolution of Neotropical frogs
Stephanie Martin: evolution of mammals
Past graduates:
Jim Cooper (MS 2000; now a post-doc at Cornell): developmental constraints and the evolution of marsupial limb diversity.
Brian Storz (MS 2003, PhD candidate at FSU): adaptive plasticity and systematics in spadefoot toads.
James Albright: (MS 2004) phylogeography of Phyllotis.
Jenner Banbury: phylogeography and systematics.
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The primary focus of current research in my lab is molecular systematics of various diverse rodent groups. These include the families Sciuridae (squirrels), Muridae (mice, rates, hamsters, and relatives), subfamily Sigmodontinae (Neotropical mice and rats), and several genera within these groups, such as Apomys, Marmota, and Phyllotis. These phylogenies then form the frameowrk for several comparative studies of quantitative genetics, vertebral evolution, and biogeography. |
Multigene phylogeny of the muroid rodents. I am collaborating with Ron Adkins at the Univ. Tennessee, Memphis on a large sequencing effort to resolve one of the most intractable problems in mammals by dense taxon sampling, a large amount of slowly evolving sequence data, and developing new genes for mammalian phylogenetics. (See publication page for some Results)
Phylogeography and quantitative genetics in Phyllotis. In collaboration with Angel Spotorno and Laura Walker (Universidad de Chile) and Oswaldo Ramirez (Universidad de Heredia Cayetano, Lima) I am conducting phylogenetic analyses of multiple mitochondrial and nuclear genes for the Phyllotis darwini species group. Detailed population level sampling is testing species limits and biogeographic hypotheses, particular the role of the Andes on speciation patterns. Controlled breeding programs in four species will be used to estimate genetic variance-covariance (G) matrices to examine how G matrices evolve. These G matrices in turn will calibrate phenotypic covariance matrices from over 30 populations.
Phylogeny and historical biogeography in Apomys. Apomys is an endemic philippine rat (Muridae) that has diversified on the many islands of the Philippines. In collaboration with Larry Heaney (Field Museum of Natural History) we are producing a molecular phylogeny for the genus using cyt b (Steppan et al. 2004) and four nuclear genes. We are then using the phylogeny to test models of historical biogeography based on Pleistocene sea level fluctuations.
Constraints on the evolution of the vertebral column in rodents. I am studying the role of developmental constraints on the evolution of the vertebral column of rodents, focusing on the tail. Many comparative studies of developmental constraints, adaptation, key innovations, and the like, are hampered by a lack of statistical power stemming from the relatively small number of data points. I am focusing on the tail of speciose mammalian groups to maximize the sampling of morphological transitions during evolution. The key questions are whether there is a bias shaping the evolution of the vertebral column and if one component of morphology appears favored due to genetic or developmental biases. To provide the framework or the comparative analyses, I have composited a phylogeny for over 240 species of myomorph rodents from published phylogenies and mapped vertebral characters onto it.
Frequency of Evolutionary Transitions in Rib Number
Molecular phylogeny of the squirrels. We have sequenced all tribes and major groups in the family Sciuridae for two nuclear genes, RAG1 (2,100 bp) and c-myc (2,100 bp), in collaboration with Robert Hoffmann (Smithsonian Institution). Several unexpected clades are revealed and the current taxonomy does not reflect the phyloeny. Most significantly, the flying squirels (Subfamily Petauristinae) appear monophyletic but they are not the sister-group to the remaining squirrels (Sciurinae). Instead they are nested within Sciurinae and are most closely related to the Neotropical tree squirrels.
Summary Results and publication pdf
A list of publications can be found on this page with links to paper summaries, figures, and full-text pdf files.
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A distributed Internet project providing comprehensive and integrated information about phylogeny and biodiversity, developed by David and Wayne Maddison, Univ. of Arizona. My contribution includes Rodentia and the superfamilies Muroidea (mice, rats, hamsters, etc...), Sciuroidea (squirrels) and various subgroups. |
 Tree of Life Home Page My contributions to the Tree of Life (rodent pages) |
| Ph.D. | 1995. | University of Chicago. Evolutionary Biology |
| M.S. | 1992. | University of Chicago. Evolutionary Biology. |
| M.A. | 1988. | San Diego State University. Geography |
| B.A. | 1983. | University of California, Berkeley. Biology and Geography |
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Ecology and Evolution at FSU
Department of Biological Science 850.644.6536 |
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PHOTOGRAPHY
A selection of photographs from my portfolio. Colonnade, Ayia Triadha Monastery, Crete. Images are for viewing only. Reproduction or electronic distribution without written consent is prohibited. |
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