Two subspecies of Toco Toucan currently are recognized, although the two subspecies are very similar, and apparently intergrade across a broad front. Northern nominate toco occurs in the Guianas and in northern Brazil. More southern albogularis occurs from Bolivia northeast across Brazil to Piauí and Bahia, and south to northern Argentina and Paraguay; but the two subspecies intergrade from Bolivia across central Brazil to Piauí. Differences between the two subspecies are slight; albogularis is said to be slightly smaller (although this is not borne out by Measurements) with a shorter bill, and a whiter throat.
Haffer (1974) identified two clades of Ramphastos toucans, based on the patterns of the vocalizations and on bill structure. The first of these clades contains the species known as the "smooth-billed yelpers," which consists of the Chestnut-mandibled Toucan (R. swainsonii), Black-mandibled Toucan (R. ambiguus), and White-throated Toucan (R. tucanus). The other clade, known as the "channel-keel-billed croakers," includes the Toco Toucan, Red-breasted Toucan (R. dicolorus), Keel-billed Toucan (R. sulfuratus), Choco Toucan (R. brevis), and Channel-billed Toucan (R. vitellinus). These clades largely were confirmed by phylogenetic analysis of DNA sequence data (Weckstein 2005, Patané et al. 2009), but the croaking toco is the basal species of Ramphastos, rather than being embedded within the clade of channel-keel-billed croakers.