Biogeographical evidence for common vicariance and rare dispersal in a southern Appalachian harvestman (Sabaconidae, Sabacon cavicolens)

Aim: Species or higher taxa that are obviously dispersal-limited, but which occupy large geographical distributions, represent a biogeographical paradox. Dispersal must have happened, likely under special and infrequent environmental conditions, but details have been lost to history. The overarching goal of our research is to understand the details of a ‘common vicariance, rare dispersal’ biogeographical history in a widespread but habitat-specialized harvestman species (Sabacon cavicolens) with a southern Appalachian centre of distribution. Location: Eastern North America, southern Appalachians. Methods: We assessed cryptic speciation using mitochondrial and nuclear gene DNA sequence data, testing alternative delimitation hypotheses using multispecies coalescent analyses. We also tested whether riverine barriers are associated with mitochondrial genealogical structuring, focusing on multiple rivers in the southern Blue Ridge physiographical province. Finally, we conducted population ...