Who made the Oldowan? Reviewing African hominin fossils and archaeological sites from 3.5 million years ago

The question of which African hominin taxon/taxa was responsible for producing Oldowan stone tools has persisted for nearly a century. Homo habilis, Paranthropus boisei, Homo erectus, Australopithecus garhi, and Australopithecus africanus, among others, have been proposed as candidates, but we have never had a definitive answer to ‘who made the Oldowan’. We review the hominin taxa that overlap temporally with the Oldowan, and use optimal linear estimation modeling to estimate first and last appearance dates for each taxon and the Oldowan. These modeled temporal trends suggest the Oldowan emerged c. 3.25 Ma lasting until either 1.6 or 1.2 Ma, a time span that would make the Oldowan the longest-lived human cultural tradition. The modeled emergence of the Homo genus and extinction of early Homo coincide well with the first and last appearance dates of the Oldowan, but there is also considerable temporal overlap between the Oldowan and other hominin taxa, particularly Paranthropus boisei. Early members of the Homo genus remain the principal candidate for making and using the Oldowan throughout its shorter modeled temporal range (c. 3.25–1.6 Ma), and, if the Oldowan was produced until 1.2 Ma, P. boisei is the prime candidate for producing these later artifacts.