Phylogenetic and morphologic evidence confirm the presence of a new montane cloud forest associated bird species in Mexico, the Mountain Elaenia (Elaenia frantzii; Aves: Passeriformes: Tyrannidae)

Here we provide evidence to support an extension of the recognized distributional range of the Mountain Elaenia ( Elaenia frantzii ) to include southern Mexico. We collected two specimens in breeding condition in northwestern Sierra Norte de Chiapas, Mexico. Morphologic and genetic evidence support their identity as Elaenia frantzii . We compared environmental parameters of records across the entire geographic range of the species to those at the northern Chiapas survey site and found no climatic differences among localities.