Phylogeography of the desert scorpion Mesobuthus mongolicus illuminates a route out of Central Asia and Junggar Basin as a corridor for faunal exchange between Central and East Asia

A comprehensive understanding of the ecological, evolutionary and genetic consequences of climate changes requires integration of information from different geographic regions and ecosystems. However, a clear knowledge gap exists in arid biota of Asian drylands, where climate change and biological evolution demonstrate high regional specificity. We report here our phylogeographic study on the desert scorpion Mesobuthus mongolicus, attempting to narrow the gap. Range wide samples for one mitochondrial gene and three nuclear loci were subjected to phylogenetic inferences, molecular dating, Bayesian phylogeographic and demographic reconstructions, and population genetic analyses. Ecological niche modeling was employed to generate models of potential distribution range at present and during the last glacial maximum (LGM). Our results revealed that M. mongolicus represents a single coherent lineage that diverged with its most closely related lineage from Central Asia about 1.36 Ma and underwent radiation ever since. Bayesian phylogeographic reconstruction suggested the ancestral population of M. mongolicus dispersed gradually eastward through the Junngar Basin to the Gobi region during the late Pleistocene, strengthening the view that the Junggar Basin has constituted an important corridor for faunal exchange between Central Asian and East Asia. We found that the desert scorpion underwent demographic expansion while experiencing range contraction during the LGM. Development of sandy deserts in northwest China incurred by Eurasian aridification might have opened up substantial empty niches that sustained population expansion during the LGM. Our results suggested that organisms ecological adaptations have acted as an important determinant for their phylogeographic and demographic responses to past climate changes.