SRA

The most striking feature of peafowl (Pavo) is the males' elaborate train, which exhibits ocelli (ornamental eyespots) that are under sexual selection. Two additional genera (Polyplectron and Argusianus) exhibit ocelli, but there is substantial variation among genera in the appearance and location of eyespots, raising the question of whether ocelli are homologous. Within Polyplectron, ocelli appear to be ancestral, suggesting ocelli may have evolved even earlier, prior to the divergence of different genera. However, it remains unclear whether Pavo, Polyplectron, and Argusianus form a clade. We estimated the phylogeny of ocellated species and their likely relatives using sequences from 1966 ultraconserved elements (UCEs) and three mitochondrial regions. The phylogeny suggested that the three ocellated genera are in the same clade, but also that each ocellated genus is sister to at least one genus without ocelli. Indeed, Polyplectron and Galloperdix, a genus not previously suggested to be related to any ocellated taxon, were found to be sister genera. The close relationship between taxa with and without ocelli suggests either that ocelli have been lost repeatedly, or gained independently. Although independent gains may be considered unlikely, this could reflect a pre-existing bias for eye-like structures among females and/or the existence of a simple mutational pathway for the development of ocelli.