Currently 8 subspecies of Northern 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), Short and Horne (2001), and Winker (2016), except where otherwise noted:
"Emerald" group, composed of 4 subspecies; collectively characterized by white or whitish throat and sides of the face below the eye, and by the maxilla being extensively yellow, except for a black patch at the nares:
prasinus, described as Pteroglossus prasinus Gould 1834; type locality "México" = Valley Real
Southeastern Mexico in Veracruz, San Luis Potosí, Hidalgo and Oaxaca; see Detailed Description.
warneri, described as Aulacorhynchus prasinus warneri Winker 2000; type locality Volcán San Martín, Sierra de Los Tuxtlas, Veracruz, Mexico
Similar to nominate prasinus, but the throat has a yellowish wash, and there is a "moderately bright yellowish band" on the auriculars (Winker 2000). Restricted to the Tuxtlas.
virescens, described as Aulacorhynchus prasinus virescens Ridgway in 1912; type locality Chaniguas, Honduras
southeastern Mexico, northern Guatemala, southeastern Mexico in Quintana Roo, Belize, Honduras, and northern Nicaragua
Similar to nominate prasinus, but the rear of the auriculars and throat are yellower; has less of a blue tint on the breast; yellower flanks and sides; darker chestnut tips to the rectrices; and is slightly smaller.
volcanius, as Aulacorhynchus prasinus volcanius Dickey and van Rossem 1930; type locality Volcán San Miguel, El Salvador
Volcán San Miguel, eastern El Salvador.
Very similar to other members of the Emerald group, but paler, and slightly smaller, although with a bill as long or longer than in adjacent populations.
"Wagler's" group, composed of a single subspecies. The bill is mostly black, with a broad yellow stripe along the culmen, and a prominent vertical orangey brown stripe at the base. The forecrown is paler, yellowish white. grading into an olive crown and yellower. Throat and sides of the face below the eye white (as in the Emerald group) but the rear margin is bluer.
wagleri, described as Pteroglossus wagleri Sturm and Sturm 1841; no type locality specified
southwestern Mexico in Guerrero and western Oaxaca.
"Blue-throated" group, composed of 2 subspecies. The throat and lower sides of the face are deep blue. The bill is mostly black, with a broad yellow stripe along the culmen; base of the culmen is chestnut.
maxillaris, described as Aulacororhynchus cæruleigularis maxillaris Griscom 1924; type locality Guaybo, Costa Rica
Costa Rica and western Panama (Chiriquí). This subspecies has been considered as a synonym of caeruleogularis (Short and Horne 2001).
caeruleogularis, described as Aulacorhamphus cæruleigularis Gould 1854; type locality Veragua; restricted to Cerro Flores, eastern Chiriquí, Panama by Griscom 1924
Panama in eastern Chiriquí and Veraguas
"Violet-throated" group, composed of a single subspecies. Similar to the "Blue-throated" group (throat and lower sides of the face deep blue; bill mostly black, with a broad yellow stripe along the culmen), but the crown and upper back are greener (less bronzy). Base of the culmen is black (not chestnut).
cognatus, described as Aulacorhamphus cæruleigularis cognatus Nelson 1912; type locality Mt. Pirre, Darién, Panama
easternmost Panama (Darién), including Cerro Tacarcuna, on the Panama/Colombia border