PARENT SESSION

Systematics/Zoogeography 3 -- Session Chair: Phil Sudman-- Nelson Hall East, Goodwin Forum

PHYLOGEOGRAPHY OF THE BERINGIAN MEMBERS OF THE SOREX CINEREUS COMPLEX. Eric Waltari¹ and Joseph A. Cook². ¹ Department of Biological Sciences, Idaho State University, Pocatello, ID; ² Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM.

ABSTRACT- The arctic and subarctic regions have experienced extensive climate-driven changes in the Quaternary due to numerous glacial-interglacial cycles. Glaciations isolated populations and in some cases led to evolutionary divergence. Lower sea levels allowed the exchange of Asian and American biota across the crossroads known as Beringia, an immense high latitude refugium. These climate-driven events led to intricate phylogeographic patterns in Beringian mammals. Shrews in the Sorex cinereus complex have a Holarctic and trans-Beringian distribution. Previous research uncovered close relationships between the Beringian and mid-latitude xeric species of the complex, and found evidence of a northward colonization of high latitudes by S. cinereus sensu stricto. To further assess phylogenetic and geographic structuring of this complex, we sequenced a portion of the mitochondrial control region, as well as two nuclear markers, from 23 shrew populations. We compare our nuclear phylogenies with mitochondrial perspectives and estimate historical demographic parameters, particularly population size and genetic diversity. We then compare these parameters across clades in the complex to test the theoretical expectation that recently expanding populations leave distinct genetic signatures.

KEY WORDS: Beringia, Arctic, shrews