New African species in the Drosophila obscura species group: genetic variation, differentiation and evolution

The Drosophila obscura species group was known in the Afrotropical region from a single species, D. microlabis . This species was recently rediscovered in Kenya in addition to the discovery of three new obscura group species: D. kitumensis, D. cariouae and D. krimbasi . The patterns of allozyme variation in two African species, D. microlabis and D. kitumensis is compared to that of nine species of the obscura group. Genetic distances have been estimated from allelic frequencies at 35 loci and phytogenies inferred by methods assuming both constant as well as variable evolutionary rates. D. microlabis and D. kitumensis are evolutionary related and close to the Palearctic D. tristis and D. ambigua even if relatively distant. The data support Lakovaara and Saura's hypothesis recognising three species subgroups within the obscura group. In addition, we propose a fourth one for the new African species, the microlabis species subgroup