Dr. Scott J. Steppan
My research is focused on understanding the origin of biological diversity. To address this long-term goal, I study highly diversified groups of animals (primarily rodents) ranging from species to ordinal levels. I reconstruct the phylogenetic relationships of these diverse groups to use as the framework for other analyses of diversification. My primary groups of interest are the muroid rodents, by far the most diverse group of mammals with 1,5000 species, and various sub-groups among the muroids, especially the South American sigmodontine mice (>360 species), and the Andean leaf-eared mice, Phyllotis. These phylogenies are then used to study morphological evolution, patterns of diversification, biogeography, and comparative quantitative genetics. Our techniques include phylogenetic analyses of DNA sequence (primarily large data sets with multiple nuclear genes) and morphological data, comparative analyses of covariation among traits, developing the comparative tools to test these multivariate patterns, analysis of geographic variation, and alpha-level systematics of living and fossil material. Go to my Home Page link above for more information.
I welcome students working in any of the general fields described above. Because my research is fundamentally question generated and not taxon based, students need not work on the same groups of animals that form the core of my current research.Selected Publications:
2012 Erickson, G. M., Gignac, P. M., Steppan, S. J., Lappin, A. K., Vliet, K. A., Brueggen, J. D., Inouye, B. D., Kledzik, D., Webb, G. J. W.. Insights into the ecology and evolutionary success of crocodilians revealed through bite force and tooth pressure experimentation PLoS ONE 7(3): e31781. doi:10.1371/journal.pone.0031781.
2011 Steppan, S..J., Kenagy, G. J., Zawadzki, C., Robles, R., Lyupanova, E.A., and Hoffmann, R.S. Molecular data resolve placement of the Olympic marmot and estimate dates of trans-Beringian interchange. Journal of Mammalogy. 92(5):1028-1037.
2011 Burns, J. H., Faden, R. B., and Steppan, S. J. Phylogeny of Commelinaceae inferred from nuclear ribosomal and chloroplast DNA sequences. Systematic Botany. 36(2):268-276..
2011 Lawrence R. Heaney, Danilo S. Balete, Eric A. Rickart, Phillip A. Alviola, Mariano Roy M. Duya, Melizar V. Duya, M. Josefa Veluz, Lawren VandeVrede, and Scott J. Steppan. Seven new species and a new subgenus of forest mice (Rodentia: Muridae: Apomys) from Luzon Island, Philippines. Fieldiana: Life and Earth Sciences 2: 1-60.
2010 Cooper, J., and Steppan, S. J. Developmental constraint on the evolution of marsupial forelimb morphology. Australian Journal of Zoology. 58: 1-15.
2010 van der Linde, K., Houle, D., Spicer, G., and Steppan, S. J. A supermatrix analysis of the family Drosophilidae. Genetics Research. 92: 25-38.
2008 Harshman, J., Braun, E. L., Braun, M. J., Huddleston, C. J., Bowie. R. C. K., Chojnowski, J. L., Hackett, S. J., Han, K-L., Kimball, R. T, Marks, B. D., Miglia, K. J., Moore, W. S., Reddy, S., Sheldon, F. H., Steadman, D. W., Steppan, S. J., Witt, C. J., and Yuri, T. Phylogenomic evidence for multiple losses of flight in ratite birds. Proceedings of the National Academy of Science 105 (36): 13462-13467.
2008 Good, J. M., Hird, S., Demboski, J. R., Steppan, S. J., Martin-Nims, T.R., and Sullivan, J. Ancient hybridization and mitochondrial capture between two distantly related species of chipmunks (Tamias: Rodentia). Molecular Ecology. 17(5):1313-1327.
2008 Rowe, K., Reno, M. L., Richmond, D. M., Adkins, R. M., and Steppan, S. J. Pliocene colonization and adaptive radiations in Australia and New Guinea (Sahul): Multi-locus systematics of the Old Endemic rodents (Muroidea: Murinae). Molecular Phylogenetics and Evolution. 47:84-101.
2007 Steppan, S. J., Ramirez, O., Banbury, J., Huchon, D., Pacheco, V., Walker, L, and Spotorno, A.O.. A molecular reappraisal of the systematics of the leaf-eared mice Phyllotis and their relatives. Pp. 799-820 in The quintessential naturalist: honoring the life and legacy of Oliver P. Pearson (Kelt, D. A., E. P. Lessa, J. A. Salazar-Bravo, and J. L. Patton, eds.). University of California Publications in Zoology 134.
2004 Steppan, S. J., Adkins, R., and Anderson, J. Phylogeny and divergence date estimates of murid rodents based on multiple nuclear genes. Systematic Biology. 53(4):533-553.
2004 Holliday, J. A. and Steppan, S. J. Evolution of hypercarnivory: the effect of specialization on morphological and taxonomic diversity. Paleobiology. 30(1):108-128.
2004 Steppan, S. J., Storz, B. L., and Hoffmann, R. S. Nuclear DNA phylogeny of the squirrels (Mammalia: Rodentia) and the evolution of arboreality from c-myc and RAG1. Molecular Phylogenetics and Evolution. 30:703-719.
2003 Steppan, S. J., Zawadzki, C., and Heaney, L. R. Molecular phylogeny of the endemic Philippine rodent Apomys (Muridae) and the dynamics of diversification in an oceanic archipelago. Biological Journal of the Linnean Society. 80:699-715.
2002 Steppan, S.J., Houle, D., and Phillips, P.C. Comparative quantitative genetics: evolution of the G matrix. Trends in Ecology and Evolution. 17:320-327.
2002 Kuch, M., Rohland, N., Betancourt, J., Lattore, C., Steppan, S.J., and Poinar, H.N. Molecular Analysis of a 11,700-yr old rodent midden from the Atacama Desert Chile. Molecular Ecology. 11:913-924.
1999 Steppan, S.J., Akhverdyan, M. R., Lyapunova, E.A., Fraser, D.G., Vorontsov, N.N., Hoffmann, R.S., and Braun, M.J. Molecular phylogeny of the marmots (Rodentia: Sciuridae): tests of evolutionary and biogeographic hypotheses. Systematic Biology. 48(4):715-734.
1997 Steppan, S.J. Phylogenetic analysis of phenotypic covariance structure. II. Reconstructing matrix evolution. Evolution. 51(2): 587-594.
1995 Steppan, S.J. Revision of the tribe Phyllotini (Rodentia: Sigmodontinae) with a phylogenetic hypothesis for the Sigmodontinae. Fieldiana: Zoology. n.s. 80:1-112.Postdoctoral Associates: