and biogeography

This paper investigates the usefulness of two mitochondrial genes (16S rRNA and cytochrome b) to solve taxonomical diYculties within the genus Hylomyscus and to infer its evolutionary history. Both genes proved to be suitable molecular markers for diagnosis of Hylomyscus species. Nevertheless the resolving powers of these two genes diVer, and with both markers (either analyzed singly or in com-bination), some nodes remain unresolved. This is probably related to the fact that the species emerged during a rapid diversiWcation event that occurred 2–6 Myr ago (4–5 Myr ago for most divergence events). Our molecular data support the recognition of an “aeta ” group, while the “alleni ” and “parvus ” groups are not fully supported. Based on tree topology and genetic divergence, two taxa generally recog-nized as subspecies should be elevated at the species level (H. simus and H. cf kaimosae). H. stella populations exhibit ancient haplotype segregation that may represent currently unrecognized allopatric species. The existence of cryptic species within H. parvus is questioned. Finally, three potentially new species may occur in West Central Africa. The Congo and Oubangui Rivers, as well as the Volta and Niger Rivers and/or the Dahomey gap could have formed eVective barriers to Hylomyscus species dispersal, favoring their speciation in allopa-try. The pronounced shifts in African climate during the late Pliocene and Miocene, which resulted in major changes in the distribution and composition of the vegetation, could have promoted speciation within the genus (refuge theory). Future reports should focus on th