We summarize our re-examination and extension of the Groves (2001) parsimony analysis of Woolly monkeys, genus Lagothrix, which led him to conclude that the species flavicauda is not most closely related to lagotricha but to Ateles, the Spider monkeys. As a consequence, Groves further proposed that the Yellow-tailed woolly monkey should be assigned to a separate genus, Oreonax, previously erected by Oldfield Thomas (1927). Our analysis, while closely following his methods, samples a greater diversity of species and sub-species representing all the living ateline genera and makes minor revisions in Groves' data matrix of craniodental characteristics. With this broader analysis we show that Groves' cladistic results cannot be replicated except by duplicating his study using only a restricted range of taxa. A more wide ranging taxonomic sampling fails to link consistently flavicauda and other ateline species, in any particular cladogram topology, while the overall craniodental morphology of flavicauda does not separate it from lagotricha. Groves' cladistic conclusion is likely to be an artifact stemming from a chance combination of the particular taxa used as a study group and selection of characters that may not be appropriate in intergeneric comparison. There is thus no justification for recognizing Oreonax as a distinct genus, and its usage should be rejected.