Phylogeography of a widespread sub-Saharan murid rodent Aethomys chrysophilus: the role of geographic barriers and paleoclimate in the Zambezian bioregion

Abstract

AbstractMurid rodents of the genusAethomysare one of the most common rodents in drier habitats in sub-Saharan Africa. Among them, the red veld ratAethomys chrysophilusis the most widespread species with the core distribution located in the Zambezian bioregion. In this study, we describe phylogeographic structure of the species and estimate its age from a time-calibrated phylogeny of the genus. Seven parapatric clades were identified in the mitochondrial cytochromebphylogeny, where some of the distributions of these clades have been separated by previously described biogeographical divides (Zambezi-Kafue river system, Rukwa Rift and the Eastern Arc Mountains). One internal clade corresponded to populations previously described as a distinct species,Aethomys ineptus. The wholeA. chrysophiluscomplex was estimated to be 1.3 (0.5–2.4) Mya old, withA. ineptusoriginating 0.7 (0.1–1.4) Mya before present. The internal position ofA. ineptuswas also recovered in phylogenetic reconstruction based on two nuclear genes and thus it is not a consequence of mitochondrial introgression. In addition, we analyzed skull form variation across the species’ distributional range and found no significant difference betweenA. ineptusand the rest ofA. chrysophiluscomplex.