Speciation at the Mogollon Rim in the Arizona Mountain Kingsnake (Lampropeltis pyromelana)

► Coalescent methods delimited species and estimated speciation process in Lampropeltis pyromelana. ► Two species were detected that likely originated prior to the Pleistocene. ► Allopatric speciation with little or no gene flow was the mode of diversification. ► Populations were fairly stable throughout the Pleistocene.