A century after a small fossil skull from a South African limestone quarry changed ideas about human origins, it remains the only specimen that can be called, without dispute, Australopithecus africanus. A new study led by Professor Gabriele Macho from the Vrije Universiteit Brussel and University College London dates the famed fossil to about 3 million years ago and suggests South Africa’s early hominins may have varied because of shifting climates and interbreeding.
Australopithecus africanus. Image credit: J.M Salas / CC BY-SA 3.0.
The Taung child, found in 1924 at the Buxton Limeworks in South Africa and described a year later by the Australian anatomist and anthropologist Raymond Dart, is the reference specimen for Australopithecus africanus.
“For over 100 years, we assumed the Taung child was just one of many similar fossils from the era,” Professor Macho said.
“Our findings turn that on its head. The human family tree wasn’t a neat, straight trunk — it was a chaotic, tangled bush driven by climate shifts.”
The skull’s exact position in the quarry was lost during mining, and earlier estimates ranged from about 942,000 to 3.03 million years.
Using uranium-lead dating of a flowstone that overlies the fossil-bearing deposit, Professor Macho and his colleagues arrived at a minimum age of 2.962 million years.
Combined with earlier magnetic evidence for a maximum age, they place the child between 2.96 and 3.03 million years ago.
They then compared the child’s teeth and brain development with those of other fossils.
Tooth-formation patterns suggest the child’s development may have slowed after its first molars emerged, as in modern humans, which hints at the start of a ‘childhood’ stage.
Models of brain growth suggest the child could have grown up to resemble some adult fossils attributed to the species, but not others.
According to the study, this leaves ‘little doubt’ about species diversity at Sterkfontein, a nearby fossil site.
The shape of the boundary between the child’s tooth enamel and dentine falls at the edge of the Australopithecus africanus range, roughly equidistant from a fossil of the species and one of the robust relative Paranthropus robustus.
To explain the diversity, the researchers turn to climate. Ocean-sediment records suggest southeastern Africa was more climatically variable between 4 and 2.5 million years ago than in the following million years or so.
Pollen from two unprovenanced samples near the Taung flowstone indicates a wetter, more wooded landscape than today’s semi-arid savanna. It includes Podocarpus, a tree now found hundreds of kilometers east.
The scientists propose that hominin populations tracked shifting habitats across a biogeographic boundary near the Limpopo River, which could have encouraged genetic drift and hybridization.
“A century after its discovery, the Taung child continues to reshape our understanding of how diverse 3-million-year-old hominin populations eventually gave rise to our own genus, Homo,” they said.
The research is described in a paper in the journal npj Palaeoecosystems.
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G.A. Macho et al. 2026. The Taung child and the biogeographic and palaeoclimatic drivers of southern African hominin diversity. npj Palaeoecosystems 1, 7; doi: 10.1038/s44513-026-00008-2
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