Taxonomy, natural history, and conservation of Paroaria baeri (Aves: Thraupidae)

Paroaria baeri (Crimson-fronted Cardinal) is a poorly known and uncommon species, inhabiting low vegetation growing along the edges of water bodies in central Brazil. Having collected new specimens along the Rio Araguaia, we revised the taxonomy of this species by examining plumage coloration and morphometric data of 36 specimens housed in Brazilian, European, and North American museums. This sample encompasses all known specimens available. Measurements of the two currently recognized subspecies overlap widely, but their plumage coloration is clearly diagnostic. Furthermore, they are distinct in the absence (Paroaria baeri baeri) and presence (Paroaria baeri xinguensis) of sexual dichromatism, and are separated by a sharp geographic barrier. These observations are consistent with the lack of gene flow between both taxa, and we propose to consider them as independent species, P. baeri, found on the Rio Araguaia, and P. xinguensis, found on the Rio Xingu. Both taxa inhabit shrubbery formations and low riparian forests along river-created habitats, P. baeri being endemic to the Cerrado and P. xinguensis being endemic to the Amazon. New information on the range, habitat, breeding, and conservation status of P. baeri is presented. We also present the first records of P. xinguensis since the collection of its type series in the 1940s.