Molecular systematics of the Drosophila hydei subgroup as inferred from mitochondrial DNA sequences.

The phylogeny of the Drosophila hydei subgroup, which is a member of the D. repleta species group, was inferred from 1,515 base pairs of mitochondrial DNA sequence of the cytochrome oxidase subunits I, II, and III. Four of the seven species in the subgroup were examined, which are placed into two taxonomic complexes: the D. bifurca complex (D. bifurca and D. nigrohydei) and the D. hydei complex (D. hydei and D. eohydei). Both complexes appear to be monophyletic, although the D. bifurca complex is only weakly supported. The evolution of chromosomal change, interspecific crossability, sperm gigantism, and divergence times of the subgroup is discussed in a phylogenetic context.