Phylogenetic relationships among the Trogons

Abstract

The order Trogoniformes currently is divided into six genera: Apaloderma, Pharomachrus, Euptilotis, Priotelus, Trogon, and Harpactes. For this study, the question of intergeneric relationships was addressed based on mitochondrial cytochrome b and 12S ribosomal RNA genes. Maximum parsimony analyses confirmed the monophyly of currently accepted genera. A monophyletic clade encompassing the New World genera was the sister group to the Asian genus Harpactes. The sister group of these clades, in turn, was the African genus Apaloderma. Within the New World clade, the sister taxon of the genus Trogon was a clade formed by the Eared Trogon (Euptilotis neoxenus) and the Quetzals (Pharomachrus spp.). The most basal genus within the New World clade was Priotelus. These results suggest an Old World (Africa/Eurasia) origin for trogons, with the New World representing a secondary area of diversification. Patterns in plumage coloration concurred with relationships inferred from the molecular data. A hypothesis for the evolution of iridescent structures in trogon feathers suggests an increase in the complexity of these structures in the youngest lineages.