to support an African origin for the trogons, with the African genus Apaloderma seemingly basal in the family, and the other two lineages, the Asian and American, breaking off between 20–36 million years ago. More recent studies show that the DNA evidence gives contradictory results concerning the basal phylogenetic relationships; so it is currently unknown if all extant trogons are descended from an African or an American ancestor or neither. The trogons are split into three subfamilies, each reflecting one of these splits, Aplodermatinae is the African subfamily and contains a single genus, Apaloderma. Harpactinae is the Asian subfamily and contains two genera, Harpactes and Apalharpactes. Apalharpactes, consisting of two species in Java and Sumatra, has only recently been accepted as a separate genus from Harpactes. The remaining subfamily, the Neotropical Trogoninae, contains the remaining four genera, Trogon, Priotelus, Pharomachrus and Euptilotis. The two Caribbean species of Priotelus were formerly different ones (Temnotrogon on Hispaniola), and are extremely ancient. The two quetzal genera, Pharomachrus and Euptilotis are possibly derived from the final and most numerous genus of trogons in the Neotropics, Trogon. A 2008 study of the genetics of Trogon suggested the genus originated in Central America and radiated into South America after the formation of the Isthmus of Panama (as part of the Great American Interchange), thus making trogons relatively recent arrivals in South America. Distribution and habitat The majority of trogons are birds of tropical and subtropical forests. They have a cosmopolitan distribution in the worlds wet tropics, being found in the Americas, Africa and Asia. A few species are distributed into the temperate zone, with one species, the elegant trogon, reaching the south of the United States, specifically southern Arizona and the surrounding area. The Narina trogon of Africa is slightly exceptional in that it utilises a wider range of habitats than any other trogon, ranging from dense forest to fairly open savannah, and from the Equator to southern South Africa. It is the most widespread and successful of all the trogons. The eared quetzal of Mexico is also able to use more xeric habitats, but preferentially inhabits forests. Most other species are more restricted in their habitat, with several species being restricted to undisturbed primary forest. Within forests they tend to be found in the mid-story, occasionally in the canopy. Some species, particularly the quetzals, are adapted to cooler montane forest. There are a number of