Filogeografia de Phaethornis bourcieri (Aves:Trochilidae): implicações taxonômicas e biogeográficas

Abstract

The Straight-billed Hermit Phaethornis bourcieri inhabits the understory of upland terra-firme forest, being distributed through most of the Amazon. Currently, two allopatric taxa considered valid and, regarded as subspecies, are included in P. bourcieri: P. b. bourcieri and P. b. major. Nonetheless, these taxa have their validity, inter-specific limits, and evolutionary history not fully elucidated. Here, we used morphological and molecular characters to review the taxonomy and propose a phylogenetic hypothesis for populations and taxa grouped under Phaethornis bourcieri. Our results showed that P. bourcieri is part of the straight-billed Hermit clade, along with P. philippii and P. koepckeae, and that the subspecies major is closer to the latter two species rather than populations grouped under nominate bourcieri. Our phylogenetic hypotheses recovered three main reciprocally monophyletic clades under nominate bourcieri separated by the Negro and Solimões rivers. These clades (along with the distantly related major) are best treated as valid phylogenetic and biological species, for which only three valid names are applicable. The diversification of the straight-billed Hermit clade (P. bourcieri, P. philippii, and P. koepckeae) is centered in the Amazon and appears to be tightly linked with the formation of the modern Amazon drainage during the Plio-Pleistocene.