Hereditas, 2003; 139: 81 – 89
Aethomys is a common and widespread rodent genus in the African savannas and grasslands. However, its systematics
and taxonomy are still unclear as no study has covered the entire range. In fact it might not be a monophyletic genus and
perhaps should be split into two subgenera, Micaelamys and Aethomys. In this paper, we present findings based on the
cytogenetics and the entire cytochrome b sequence of two species from Zambia (A. kaiseri ) and Tanzania (A.
chrysophilus), and we compare them with the sequences of a South African species (A. namaquensis) and other allied
muroid genera. Comparison of the banded chromosomes revealed complete G-band homology between the autosomes of
the two species. However, the X and Y chromosomes clearly differ in size and in C- and G-banding, being much larger
in A. kaiseri.
Comparison of the cytochrome b sequences places the separation between A. kaiseri and A. chrysophilus at 4.49 Mya,
a period of intense speciation in other African muroids. The resulting phylogeny strongly supports the idea of a
paraphyletic group, suggesting the need to elevate the previously described subgenera to the genus rank.