Karyotypic and genetic divergence in the Ethiopian Myomys - Stenocephalemys complex (Mammalia, Rodentia)

The Ethiopian Myomys - Stenocephalemys complex has long constituted a taxonomic and systematic puzzle. The species occur at different altitudes, from 1000 up to 4300 m a.s.l., and show remarkable adaptations to high altitude habitats. The four species forming the complex, M. albipes, M. ruppi, S. albocaudata and S. griseicauda, are all endemic to the country and constitute a monophyletic group. We describe their karyotypes, including their G- and C- banding patterns, and their allozyme patterns. Phylogenetic trees based on chromosomal rearrangements and al-lozymes support the current taxonomy. Nonetheless, comparisons with genetic similarity data and other hypotheses drawn from mtDNA and geometric morphometrics show substantial disagreement, and therefore it is not possible to claim the paraphyly of Stenocephalemys which would then include Myomys.