This section follows Ferguson Lees and Christie (2001), Buckley (1999) and Del Hoyo et al (1994).
C. a. atratus (Bechstein, 1973). Larger than brasiliensis, similar to foetens. Whitish primary patches. Present in North America (USA) up to the North of Mexico.
C. a. brasiliensis (Bonaparte, 1850). Smaller than other subspecies. Clearer primary patches more extensive than in the other subspecies. From central and tropical Mexico to northern and eastern South America, as far as coastal Peru, lowland Bolivia and southern Brazil.
C. a. foetens (Lichtenstein, 1817). Similar in size to atratus. Darker whitish primary patches. Central and west South America as far south as northern Patagonia.
Cathartid phylogeny has been subject of great debate for several years now (Rea 1983) and continues to be to this day (Ericson et al 2006, Brito 2008).
The New World Vultures have been grouped together with diurnal raptors by Linnaeus (1758) in a classification that related vultures from the New World and the Old World (Brito 2008). These two vulture groups are extremely similar in appearance but it is now known that it represents a clear case of convergent evolution (Del Hoyo et al 1994, Wink 1995). Still, and in spite of the early documents which suggest otherwise (e.g. Garrod 1873, 1874), New World Vultures were first placed as a family, Cathartidae, within the order of Falconiformes (Rea 1983). Later on, several studies reclaimed the proposition that cathartids should be removed of the Falconiformes order and, instead, placed them under the order of Ciconiiformes (shared by storks and herons). Such decision stemmed from behavioral and morphological affinities (Rea 1983) and molecular analyses (Ligon 1967, Sibley & Alquist 1990, Avise et al 1994). However, with the advent of new molecular techniques and methodologies such theory has not been robust enough to withstand posterior analyses. Some of these studies have been proved to be flawed (see Griffiths 1994, Wink 1995) and the more recent studies conducted with newer methodologies concluded that vultures have higher affinity with raptors and not storks (i.e. Ericson et al 2006, Fain & Houde 2004). Reappearance of Cathartidae family within the Falconiformes order is now proposed. Additionally, it has been suggested, based on phylogenetical analyses performed with osteological characters, the elevation of the hierarchical rank of the group as the Cathartiformes Seehbhom 1890 (Brito 2008). Within this order, two families: Cathartidae (including the genera Cathartes and Coragyps) and Vulturidae (including the condors and King Vulture: Gymnogyps, Vultur, Sarcoramphus, and the extant Breagyps). This new proposition is yet to be proven and further tested before it is accepted by the scientific community. In any case, its interesting and parsimonious approach to the controversy deserves due attention.