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

The Ethiopian Myomys - Stenocephalemys complex has long constituted a taxon omic 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 alb ocaudata 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 allozymes support the current taxonomy. N onetheless, comparisons with genetic similarity data and other hypotheses d rawn 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.