Philip Hershkovitz and William Charles Osman Hill published taxonomies of the capuchin monkeys in 1949 and 1960, respectively. These taxonomies included all robust capuchins, described then as the tufted group, in the single species Cebus apella, while three gracile (untufted) capuchin species were recognized. Over time, the original C. apella was split into the additional species of robust capuchin monkeys recognized today. In 2001, Silva published a study in which he found greater genetic diversity among robust capuchins than among gracile capuchins. Silva's study also concluded that due to the differences between robust and gracile capuchins, the two groups should at least be placed in separate subgenera within the genus Cebus, offering Sapajus as the subgenus name for robust capuchins. After further studies of the morphology and genetics of the capuchin monkeys, Lynch Alfaro, Silva and Rylands proposed elevating Sapajus to a separate genus in 2012.
