williams

The origin of the Oldowan stone tools has been a question for nearly a century.
Proposed candidates for creating Oldowan tools:
- Homo habilis
- Paranthropus boisei
- Homo erectus
- Australopithecus garhi
- Australopithecus africanus
Current review focuses on the hominin taxa contemporaneous with the Oldowan and employs optimal linear estimation (OLE) modeling to assess first and last appearance dates.

Oldowan tools are estimated to have emerged around 3.25 million years ago, lasting until roughly 1.6 or 1.2 million years ago, marking it as one of the longest-lasting human cultural traditions.
The emergence of the Homo genus aligns with the first appearance of the Oldowan, but there is significant overlap with other hominin taxa, particularly Paranthropus boisei.
Homo species are likely the primary makers of the Oldowan from 3.25 to 1.6 million years ago, while P. boisei may have produced tools if the Oldowan continued until 1.2 million years ago.

The Oldowan was first associated with Zinjanthropus boisei (now Paranthropus boisei) due to its discovery in the Olduvai Gorge (Leakey 1959).
Current association typically links the Oldowan with the genus Homo because of more recent evidence suggesting their larger brain size and dexterity make them better candidates for tool-making.

Increasing discoveries in both eastern and southern Africa containing Oldowan artifacts alongside only Paranthropus fossils have complicated single taxon associations (e.g., Wood 1997).
Evidence suggests Homo habilis and Homo rudolfensis, Homo erectus, P. boisei, and P. robustus as potential tool-makers.
Australopithecus garhi fossils found near evidence of butchery marks hint at participation in tool-making.

The statistical method accounts for fossil records which do not perfectly represent taxa and technologies.
Declining populations in marginal habitats make taxa unlikely to be sampled during key periods of origination/extinction;
- Fails emphasize the selectiveness of site sampling.
OLE is particularly useful in accounting for incomplete fossil records.

Utilizing available data from 3.5 to 1.5 Ma yields a dataset comprising 88 confirmed Oldowan sites and 1,878 hominin fossils.
Inclusion criteria for sites involved specific definitions of Oldowan tools, radiometric dating, and exclusion of sites with Acheulean characteristics.

Emerge at an estimate of 3,326,274 years BP, with a confidence interval extending to 4,782,097 years BP.
Grades to extinction estimates probability of 1.2 to 1.6 Ma, with intervals allowing indicators of co-existing hominin options.
The OLE models suggest that early Homo species (especially H. habilis and H. rudolfensis) are strong candidates for Oldowan creation.

Australopithecus afarensis: Known to predate the Oldowan but no overlaps with Oldowan sites.
Australopithecus africanus: Timelines suggest a higher probability of association than others.
Paranthropus boisei: Shares a large portion of its temporal range with the Oldowan but may not be definitively labeled as its maker.
Homo habilis: Range overlaps significantly with Oldowan continuities from 2.35 Ma to 1.67 Ma.
Homo erectus: Associated with later developments but not tightly linked to the Oldowan’s origins as per modeled estimates.

The Oldowan may not be attributable to one singular genus due to the overlap in findings from various taxa yielding Oldowan artifacts, implicating both Homo and Paranthropus.
Evidence suggests learning exchanges and behaviors could lead to cultural transmission between Homo and Paranthropus, with complexity well beyond traditional views of tool-making.

The analysis supports a reconsideration of what it means to be human/hominin, challenging the notion that only members of Homo could create or use technology.
Finding tool manufacture in other taxa suggests shared traits that survived in their evolutionary lines, rewriting ancestral guidance in hominin adaptations across the Pleistocene.

The complex interactions and contributions of several taxa to the Oldowan technological framework punctuate our understanding of the hominin evolutionary narrative, emphasizing that multiple genera possibly co-produced the Oldowan tools, specifically highlighting Homo and Paranthropus as key players in early stone tool culture.