The taxonomy of the polytypic and wide-ranging Gray-necked Wood-rail, Aramides
cajaneus 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 Aramides
cajaneus, all of which already had available names: Aramides
albiventris Lawrence, 1868, from southern Mexico to northeastern Costa Rica, Aramides
cajaneus (Statius Müller, 1776) (sensu stricto), from southwestern Costa Rica to Argentina, and Aramides
avicenniae Stotz, 1992, from a small section of the coast of southeastern Brazil. Aramides
albiventris presents extensive plumage variation, but with no geographic structure. The song of Aramides
cajaneus and Aramides
avicenniae is strikingly and completely different from the song of Aramides
albiventris. A previously unnoticed parapatric pattern of distribution of Aramides
cajaneus and its congener Aramides
saracura in southeastern Brazil is described, and we clarify that the name Aramides
plumbeicollis, included in the synonymy of Aramides
albiventris, was first made available in 1892, rather than in 1888 as is widely referred. In addition, plumage variation in Aramides
ypecaha, Aramides
wolfi, and Aramides
mangle is discussed.