Seven new montane species of Drosophila in the Eastern Arc mountains and Mt Kilimanjaro in Tanzania attesting to past connections between eastern andwestern African mountains (Diptera : Drosophilidae)

This report describes 7 new species of Drosophila found in the Eastern Are mountains and on Mount Kilimanjaro in Tanzania: D. baucipyga, D. gata, D. k ilimanjarica, D. neogata, D. paragata, D. pilocornuta and D. usambarensis s pp.n. Two new species complexes, the megapyga species complex (Sophophora s ubgenus, melanogaster group, montium subgroup) and the gata species complex (Drosophila subgenus) are introduced. Only one species, D. baucipyga of th e montium subgroup, has a geographical range matching the whole Eastern Arc , from the Usambara Mts. in the north-east of Tanzania to Mt. Uzungwa in th e south-south west of the country. Five others, including one representativ e of the dentissima group of the Sophophora subgenus, D. usambarensis, and four representatives of the Drosophila subgenus, D. gata, D. neogata, D. pa ragata and D. pilocornuta, were found only in the Usambara Mts. Two of thes e five, D. usambarensis and D. pilocornuta were found only in West-Usambara , while two other related species, D. gata and D. paragata, were found only in East-Usambara. Only the distribution of D. neogata covers the whole of the Usambara mountains. Outside the Eastern Are, another representative of the dentissima group, D. kilimanjarica, was found only on Mount Kilimanjaro . This new, highly specific, montane fauna of Drosophila further contribute s to the unique biological diversity of the Eastern Arc Mts. The biogeograp hic affinities of the new taxa suggest past connections with the Virunga an d Ruwenzori ranges and further west with the Cameroon Volcanic Line. It ind icates, in particular, that the Eastern Arc forests have passed through a s uccession of coalescence and fragmentation events.