My research is primarily concerned with the systematics and biogeography of localized mammalian radiations. I am currently focusing on three isolated groups of mammals: the native rodents of Madagascar, the indigenous rodents of the Philippines, and South American didelphid marsupials. Each of these groups contains species that have evolved to take advantage of a wide range of ecological conditions and exhibit a broad array of morphological adaptations. Reconstructing the evolutionary history of these groups is the first step towards understanding which forces -- biological and geological -- have prompted their diversification. I employ DNA sequence data to infer phylogenetic history, and I work with traditional systematists to combine morphological and molecular data to provide a better understanding of mammalian evolutionary history.

Jansa SA and RS Voss (2011) Adaptive evolution of the gene encoding a venom-targeted blood protein in opossums that eat pitvipers.  PLoS ONE.

Giarla TC, RS Voss, and SA Jansa (2010) Species limits and phylogenetic relationships in the didelphid marsupial genus Thylamys based on mitochondrial DNA sequences and morphology.  Bulletin of the American Museum of Natural History 346:67pp

Gutiérrez EE, SA Jansa, and RS Voss (2010) Molecular systematics of mouse opossums (Didelphidae: Marmosa): Mitochondrial evidence for genetic divergence among mophologically defined species, with comments on phylogenetic relationships and biogeography.  American Museum Novitates 3692:22pp

Voss RS, DW Fleck, and SA Jansa (2009) On the diagnostic characters, ecogeographic distribution, and phylogenetic relationships of Gracilinanus emiliae (Didelphimorphia: Didelphidae: Thylamyini).  Mastozoología Neotropical.

Heaney LR, DS Balete, EA Rickart, MJ Veluz, and SA Jansa (2009) A new genus and species of small “tree-mouse” (Rodentia, Muridae) related to the Philippine cloud rats. Bulletin of the American Museum of Natural History 331: 205-229

Voss RS and SA Jansa (2009) Phylogenetic relationships and classification of didelphid marsupials, and extant radiation of New World metatherian mammals.  Bulletin of the American Museum of Natural History 332:177pp

Jansa SA, TC Giarla, and BK Lim (2009) The phylogenetic position of Typhlomys and the geographic origin of Muroidea. Journal of Mammalogy 90:1083-1094

Goodman SM, M Raheriarisena, and SA Jansa (2009) A new species of Eliurus Milne Edwards, 1885 (Rodentia: Nesomyinae) from the Réserve Spéciale d’Ankarana, northern Madagascar.  Bonner Zoologische Beiträge 56:133-149

Jansa SA, V Soarimalala, SM Goodman, and FK Barker (2008) Morphometric and genetic variation in Macrotarsomys bastardi, an endemic dry-forest rodent from Madagascar. Journal of Mammalogy 89:316-324

Gruber KF, RS Voss, and SA Jansa (2007) Base compositional heterogeneity in the RAG1 locus among didelphid marsupials: Implications for phylogenetic inference and evolution of GC-content.  Systematic Biology  56:83-96

Rickart EA, DS Balete, R Rosell-Ambal, SA Jansa, LR Heaney (2007) Descriptions of two new species of Rhynchomys Thomas (Rodentia: Muridae: Murinae), from Luzon Island, Philippines.  Journal of Mammalogy 88:287-301

Anderson RP and SA Jansa (2007) Genetic comparisons between Heteromys desmarestianus and the recently described H. nubicolens (Rodentia: Heteromyidae) in northwestern Costa Rica. Mammalian Biology 72:54-61

Jansa, S.A., F.K. Barker, and L.R. Heaney. (2006) Molecular Phylogenetics and Divergence Time Estimates for the Endemic Rodents of the Philippine Islands: Evidence from Mitochondrial and Nuclear Gene Sequences. Systematic Biology

Jansa, S.A., J. Forsman,* and R.S. Voss (2006). Different patterns of selection on the nuclear genes IRBP and DMP-1 affect the efficiency but not the outcome of phylogeny estimation for didelphid marsupials. Molecular Phylogenetics and Evolution. (*Undergraduate Student)

Jansa, S.A. and R.S. Voss (2005). Phylogenetic relationships of the marsupial genus Hyladelphys based on nuclear gene sequences and morphology. Journal of Mammalogy. 86(5):853-865

Jansa, S.A. and M. Weksler. (2004) Phylogeny of muroid rodents: Relationships within and among major lineages as revealed by nuclear IRBP gene sequences. Molecular Phylogenetics and Evolution. 31:256-276.

Voss, R.S. and S.A. Jansa. (2003) Phylogenetic studies on didelphid marsupials II. Nonmolecular data and new IRBP sequences: Separate and combined analyses of didelphine relationships with denser taxon sampling. Bulletin of the American Museum of Natural History 276:82 pp.

Jansa, S.A., B.L. Lundrigan, and P.K. Tucker (2003) Tests of positive selection on immune and reproductive genes in the murine genus Mus. Journal of Molecular Evolution 56:294-307.

Lundrigan, B.L., S.A. Jansa, and P.K. Tucker (2002) Molecular phylogenetics of the genus Mus based on maternal, paternal, and bi-parentally inherited characters. Systematic Biology 51:410-431.

Jansa, S.A. and R.S. Voss (2000) Phylogenetic studies on didelphid marsupials I: Introduction and preliminary results from IRBP gene sequences. Journal of Mammalian Evolution. 7(1):43-77.

Jansa, S.A., S.M. Goodman, and P.K. Tucker (1999) Molecular phylogenetics of the native rodents of Madagascar: A test of the single origin hypothesis. Cladistics 15:253-270.

Education
Ph.D., University of Michigan, 1998 

Additional Links
Jansa Lab Research Page

Bell Museum of Natural History

Animal Diversity Web