The Evolutionary History of DROSOPHILA BUZZATII. III. Cytogenetic Relationships between Two Sibling Species of the Buzzatii Cluster.

Drosophila buzzatii has been found sympatric in Argentina with a closely-related sibling species, D. serido. The biogeographical, reproductive and chromosomal data allow us to combine these species into an evolutionary unit, the buzzatii cluster. Salivary gland chromosomes also have been used to determine their phylogenetic relationships with other closely related species, showing that the buzzatii cluster species share two inversions-2d(2) and 2s(6)-with the species of the martensis cluster. Both clusters arose from South American populations of the ancestor of the mulleri complex, and we propose to include D. buzzatii and D. serido in the mulleri complex of the repleta group.