Navarro et al. in their paper Species limits in Mesoamerican Aulacorhynchus toucanets, Wilson Bulletin 113, 4 (2201): 363–372, discuss a taxonomic rearrangement of the forms of Emerald Toucanet. They tentatively come forward with a split into seven species, listed below. I consider it a little premature to include these already, and it is probably wise to wait until further (genetic) evidence is presented. The porposed species and their ranges are:

Wagler's Emerald-Toucanet     A. wagleri
sw Mexico: Guerrero & sw Oaxaca

Blue-throated Emerald-Toucanet     A. caeruleogularis
Costa Rica; w Panama

"Nelson's" Emerald-Toucanet     A. cognatus
c,e Panama; w Colombia: Chocó

Santa Marta Emerald-Toucanet     A. lautus
nw Colombia: Santa Marta Mts.

"Northern Andean" Emerald-Toucanet     A. albivitta
w Venezuela; Colombia: Andean slopes; Ecuador: e Andean slope

"Peruvian" Emerald-Toucanet     A. atrogularis
s Ecuador: e Andean slope; Peru: e Andean slope & e lowlands; n,c Bolivia; w Brazil: Acre

The geographic range of the form prasinus is e,se Mexico to c Nicaragua.

Emerald Toucanet     Aulacorhynchus prasinus
(Gould)   1843
s,w Mexico to c Bolivia.  Especially montane and hill forests