Systematics

Monotypic.

There are two species in Semnornis, frantzii (Prong-billed Barbet) of Costa Rica and Panama, and ramphastinus (Toucan Barbet) of western Colombia and western Ecuador.

The traditional classification of Semnornis was in the Capitonidae, a family that included genera of barbets from the neotropics as well as from Africa and Asia (e.g., Peters 1948). More recently, phylogenetic analyses of morphological data (Prum 1988), DNA hybridization data (Sibley and Ahlquist 1990), and phylogenetic analysis of DNA sequence data (Barker and Lanyon 2000, Moyle 2004) demonstrated that the three genera of New World barbets (Capito, Eubucco, Semnornis) were more closely related to toucans (Ramphastidae) than they were to the Old World genera of barbets. Consequently, the Old World barbets were removed to different families (Lybiidae for the African taxa, and Megalaimidae for the Asian species). In view of uncertainty as to whether Semnornis (Prum 1988) or Capito + Eubucco (Barker and Lanyon 2000, Moyle 2004) were the sister to Ramphastidae, a separate family, Semnornithidae, now is recognized for Semnornis, and the family Capitonidae is restricted to Capito and Eubucco.