Phylogeography and the origins of range disjunctions in a north temperate fish, the pygmy whitefish (Prosopium coulterii), inferred from mitochondrial and nuclear DNA sequence analysis

Intraspecific range disjunctions occur when a taxon has geographic occurrences that are separated by large geographic distances, and they are one of the oldest observations in biogeography (Lomolino et al., 2006). Range disjunctions have provoked much thought in biogeography because they suggest that separate geographic areas were once connected, that longdistance dispersal has occurred between such areas, or that a once more broadly distributed taxon has become extinct in intervening areas. In fact, range disjunctions, along with resolution of the processes involved in plate tectonics, orogeny and glaciation, as well as improved methods of phylogenetic reconstruction, provided a major impetus to the origin and the development of the field of vicariance biogeography (Riddle, 1996; Lomolino et al., 2006). Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, Canada N2L 3G1, Department of Zoology and Native Fishes Research Group, University of British Columbia 6270 University Blvd, Vancouver, BC, Canada V6T 1Z4, Peace/Williston Fish and Wildlife Compensation Program, 1011 4th Ave., Prince George, BC, Canada V2L 3H9