Figure 6: A model of the evolution of phallic processes in the melanogaster species group.

A,C,E) Phylogeny of the 8 analyzed species based on Obbard et al., 2012. A) Parsimony suggests that the pregonites originated outside of the D. melanogaster species group. B) Light blue represents the pregonites and teal represents the pregonal lateral process. C) Parsimony suggests that the ventral postgonites originated in the melanogaster complex (D. melanogaster, D. simulans, D. mauritiana, D. sechellia) and that the dorsal postgonal process originated in the melanogaster subgroup. D) Magenta represents the ventral postgonal process, violet represents the dorsal postgonal process. E) Parsimony suggests that the aedeagal ventral process originated at the base of the erecta and yakuba complexes. Additionally, parsimony suggests that the aedeagal lateral process originated in the bipectinata complex. F) Dark green represents the aedeagal ventral process and yellow-green represents the aedeagal lateral process. Ventral postgonite is an alternative term for ventral postgonal process, and dorsal postgonite is an alternative term for dorsal postgonite. Future developmental analysis across more members within and outside of the D. melanogaster species group will be required to better establish when these distinct phallic processes first originated.