Diversification in the steppe rat snake <i>Elaphe dione</i> (Pallas, 1773) coincides with the Mid-Pleistocene climatic transition of Eurasia

Our study is the most comprehensive phylogeographic analysis of <i>E. dione</i> to date. The territory of central China most probably served as an ancestral area of this species, where <i>E. dione</i> diverged from its most recent common ancestor with <i>E. bimaculata</i> during the Late Miocene. The most active period of diversification in <i>E. dione</i> was estimated to have occurred later (∼1.3 Mya) than other widespread Palearctic species. Furthermore, this period is correlated across the species' range and coincides with the beginning of the Mid-Pleistocene climatic transition. Climatic and environmental transitions during this period may have triggered the allopatric divergence of <i>E. dione</i> in multiple glacial refugia. Notably, diversification in the Western Palearctic resulted in a greater number of phylogeographic lineages, which could be linked to a greater number of suitable refugia. However, further evidence is needed to confirm these scenarios.