Humboldt's Aracari is a subspecies of Lettered Aracari with dark lower mandible. Most seem to have a solid yellow front, but a few photos including this one show a faint broad band similar to the Chestnut-eared Aracari. I wonder if there has been some hybridization. This is a 'clean' Humboldt's Aracari.
This species has two forms, sometimes considered different species. Humboldt's Aracari, found in the Andean foothills from Colombia to Bolivia as well as the western Amazon basin, has an all black lower {mandible}.
Africa (entire continent rather than south of Sahara)
AN
Antarctica
AO
Atlantic Ocean
AU
Australasia (Wallacea (Indonesian islands east of Wallace's line), New Guinea and its islands, Australia, New Zealand and its subantarctic islands, the Solomons, New Caledonia, and Vanuatu)
PAL
Eurasia (Europe, Asia from the Middle East through central Asia north of the Himalayas, Siberia and northern China to Japan)
IO
Indian Ocean
LA
Latin America (Middle and South America)
MA
Middle America (Mexico through Panama)
NA
North America (includes the Caribbean)
NO
Northern oceans
OR
Oriental Region (South Asia from Pakistan to Taiwan, plus Southeast Asia, the Philippines, and Greater Sundas)