Mitu tuberosum was described as Crax tuberosa by Spix, with a type locality of "Rio Solimões, Brazil". For most of its taxonomic history, tuberosum was treated as a junior synonym of Crax mitu Linnaeus (now Mitu mitu) of northeastern Brazil (e.g., Peters 1934, Hellmayr and Conover 1942, Vaurie 1967, Blake 1977). During most of this period, there were no reports of curassows from northeastern Brazil, and the differences between nominate mitu and tuberosum were not appreciated. Pinto rediscovered nominate mitu in the early 1950s (Pinto 1952), leading to a better understanding of its characters (Pinto 1952, Sick 1980). Currently mitu and tuberosum are recognized as distinct species, which is supported by the available genetic data (Grau et al. 2003, Eo et al. 2008).
Surprisingly, tuberosum and mitu apparently are not sister species. Phylogenetic analysis of mitochondrial DNA sequence data indicates that the sister taxon of tuberosum is Pauxi pauxi Helmeted Curassow (Pereira and Baker 2004), although these authors caution that "an ancient transfer [hybridization] might have occurred. Because only one specimen of each taxon was sequenced, caution is warranted in making conclusions" (Pereira and Baker 2004: 690). See also Eo et al. (2008).