High Evolutionary and Taxonomic Diversity of Gerbils ( Gerbillus ) in the Horn of Africa

ABSTRACT The genus Gerbillus represents a striking example of successful Pleistocene radiation among rodents, resulting in nearly 50 currently recognised species distributed across Asia (from the Middle East to northwestern India) and Africa (the Saharo‐Sahelian region and eastern Africa). Over the past two decades, multiple molecular phylogenetic studies have helped elucidate the complex subgeneric structure of this speciose group. Here, by incorporating into a genetic analysis of mitochondrial and nuclear markers and using samples collected in Somaliland, Ethiopia, Kenya and Tanzania, together with available GenBank sequences of other Gerbillus species we provide, for the first time, genetic data for Microdillus peeli (a taxon whose phylogenetic position has remained unresolved for over a hundred years) and unequivocally demonstrate that it represents an internal lineage within Gerbillus. In addition, we characterise a novel lineage within the genus and attempt to decipher its phylogeographic structure. However, having failed to discriminate between genetically defined lineages using geometric morphometrics and owing to the lack of genetic data for several critically important specimens, we do not undertake a taxonomic revision or describe new taxa within the scope of the present study.