MOLECULAR PHYLOGENY OF THE PRAOMYS COMPLEX (RODENTIA, MURINAE) - A STUDY BASED ON DNA DNA HYBRIDIZATION EXPERIMENTS/

Within the Murinae (Muridae: Rodentia), the African rats of the Praomy s group, whose systematics has been studied through different approach es, have raised numerous taxonomic problems. Different taxa related to Praomys have successively been described, among which Mastomys, Myomy s and Hylomyscus were considered either as separate genera or subgener a of Praomys. In order to clarify the relationships within the Praomys group, we conducted a series of DNA/DNA hybridization experiments inv olving different species of Praomys, Mastomys, Myomys and Hylomyscus p lus other Murinae acid a Cricetomyinae. This study indicates that the Praomys complex is a monophyletic entity clearly separated from the ot her African and Asian Murinae. If Mastomys and Hylomyscus appeared to be independent genera, the taxonomic situation of Praomys and Myomys i s more difficult to ascertain. Indeed, Praomys tullbergi appears more closely related to Myomys daltoni than to another species of Praomys, namely P. jacksoni, suggesting paraphyly for Praomys. Furthermore, P. jacksoni is as distant from P. tullbergi as from any species of Mastom ys. Additional species of Praomys and, especially, of Myomys, are need ed for reaching a definitive conclusion on these latter taxa. The Prao mys group is more related to Mus than to Rattus. To calibrate our mole cular distances with geological time, we used a dating of 10 Myr for t he Mus/Rattus dichotomy. The inferred rate of molecular evolution sugg ests a dating of c. 8 Myr for the separation of the Praomgs group from the Mus lineage.