Abstract
The taxonomy of the polytypic and wide-ranging Gray-necked Wood-rail, Aramidescajaneus is reviewed, based on external morphology and voice. Throughout its distribution, there is extensive plumage variation, much of it taxonomically uninformative. However, through three informative plumage characters, as well as morphometric and vocal variation, three phylogenetic species were identified within what is today known as Aramidescajaneus, all of which already had available names: Aramidesalbiventris Lawrence, 1868, from southern Mexico to northeastern Costa Rica, Aramidescajaneus (Statius Müller, 1776) (sensu stricto), from southwestern Costa Rica to Argentina, and Aramidesavicenniae Stotz, 1992, from a small section of the coast of southeastern Brazil. Aramidesalbiventris presents extensive plumage variation, but with no geographic structure. The song of Aramidescajaneus and Aramidesavicenniae is strikingly and completely different from the song of Aramidesalbiventris. A previously unnoticed parapatric pattern of distribution of Aramidescajaneus and its congener Aramidessaracura in southeastern Brazil is described, and we clarify that the name Aramidesplumbeicollis, included in the synonymy of Aramidesalbiventris, was first made available in 1892, rather than in 1888 as is widely referred. In addition, plumage variation in Aramidesypecaha, Aramideswolfi, and Aramidesmangle is discussed.