Up to 7 subspecies of Southern Emerald-Toucanet are recognized, which primarily vary in the color of the throat and of the bill. These subspecies can be divided into up to 4 groups (which sometimes are recognized as separate species; see also Related Species). The following short descriptions are based on Haffer (1974) and Short and Horne (2001), except where otherwise noted:
"Santa Marta Toucanet" group, composed of a single subspecies. Characterized by a pale gray throat. The bill is mostly black, with a yellow strioe along the culmen. Orbital skin orange-grown or gray.
lautus, described as Aulacorhamphus lautus Bangs 1898; type locality San Miguel, Santa Marta mountains, Colombia
Sierra Nevada de Santa Marta, Colombia
"Andean Toucanet" group, composed of two subspecies.
albivitta, described as Pteroglossus albivitta Boissonneau 1840
Andes of northwestern Venezuela, east slope of Central Andes and both slopes of Eastern Andes of Colombia, and eastern Andes of Ecuador (except for southeast)
Characterized by a white throat. Feathers surrounding the bare orbital skin (which is yellow to orange) are blue. The bill is mostly black, with a broad yellow stripe on the culmen; there also often is some chestnut or marroon near the base of the mandible.
phaeolaemus, described as Aulacorhamphus phaelæmus Gould 1874; type locality Concordia in Colombia and Mérida in Venezuela; restricted by Hellmayr (1911: 1213) as the western Andes of Colombia (see also Haffer 1974: 196).
Western Andes, Colombia (except for the northern end)
Throat pale blue. Bill mostly black, with a broad yellow stripe along the culmen, and some chestnut near the base of the mandible; vertical stripe at base of bill white.
"Gray-throated Toucanet" group, composed of a single subspecies. Characterized by a pale gray throat. Bill mostly black, with a broad yellow stripe along the culmen, and some chestnut near the base of the mandible; vertical stripe at base of bill white.
griseigularis, described as Aulocorhynchus [sic] albivitta griseigularis Chapman 1915; type locality Santa Elena, Colombia
northern portion of Western Andes, and the west slope of the Central Andes, of Colombia
"Black-throated Toucanet" group, composed of 3 subspecies. Characterized by deep blue (cyanolaemus) or black (atrogularis, dimidiatus) throat. Bill mostly black, with broad yellow stripe on culmen (or, in cyanolaemus, yellow restricted to tip of maxilla).
cyanolaemus, described as Aulacorhamphus cyanolæmus Gould 1866; type locality Loxa [Loja], Ecuador
east slope of the Andes of southeastern Ecuador and northern Peru. Some specimens from south of the Rio Marañon in northern Peru were thought by Haffer (1974) to represent intergrades with atrogularis; these specimens are large and have blue throats (as in cyanolaeamus), but have intermediate bill colors. The distributions of these two subspecies are not yet known to be in contact (see Distribution), although this apparent gap may be an artifact of incomplete sampling. The elevational distributions of cyanolaemus and atrogularis also are different, however, further suggesting that there may be little or not direct introgression between these two taxa.
atrogularis, described as Pteroglossus atrogularis Sturm 1841; type locality "Andes of Peru", restricted by Cory (1919: 380) to Chanchamayo, Peru
east slope of the Andes from central Peru to Bolivia. Some specimens from south of the Rio Maranon in northern Peru were thought by Haffer (1974) to represent intergrades with cyanolaemus; these specimens are large and have blue throats (as in cyanolaemus), so not show any evidence of introgression in plumages, but the bills of these specimens are more extensively yellow than is typical of cyanolaemus. As pointed out by Dan Lane (personal communication to TSS), however, "cyanolaemus and atrogularis seem to occupy distinctly different elevational ranges (the former 1100-2000m, above A. derbianus [Chestnut-tipped Toucanet], the latter lowlands up to about 800m, below A. derbianus) makes me doubt that the two have much opportunity to intergrade".
dimidiatus, described as Aulacorhamphus dimidiatus Ridgway 1886; type locality presumed to be "some portion of the Upper Orinoco region, in Venezuela, or contiguous portion of the Rio Negro basin" , but Hellmayr (1920) suspected that it originated from northern Peru, and O'Neill and Gardner (1974) concluded that the type locality "must be along the eastern foothills of the Andes of central southern Peru".
foothills of the Andes and adjacent western Amazonia in southeastern Peru and northern Bolivia. Differs from atrogularis primarily by smaller size, especially by the shorter bill.