Lake Turkana footprints blur the body-size divide between Paranthropus and Homo
Primary source: Max Planck Society ↗
Source: “Fossil footprints reveal body size and group dynamics of a 1.4-million-year-old human relative” — Max Planck Society ↗, 27 July 2026
Archaeonews Summary
At GaJi10 in the Koobi Fora Formation on Lake Turkana’s eastern shore in northern Kenya, researchers documented 21 hominin footprints representing at least eight individuals on a single Early Pleistocene surface. The tracks were first exposed in 1978 during geological trenching, then reburied for protection and reopened in 2016 and 2023, when additional prints were uncovered. The surface is placed at about 1.43 million years ago from a volcanic-ash horizon in the surrounding strata. ([Smithsonian Institution][1])
The study was led by Kevin Hatala of Chatham University and the Max Planck Institute for Evolutionary Anthropology, with Kenyan and US collaborators including the National Museums of Kenya and Smithsonian. The team compared footprint shape and inferred locomotion with track morphologies identified in earlier work. Those features favour Paranthropus boisei, while the unusually large prints imply bodies reaching roughly 1.8 metres and 75 kilograms. The work was published in PNAS. ([MPG][2])
Why It Matters
The strongest result is not a definitive portrait of a tall, male Paranthropus group, but a mismatch between anatomy and size. The tracks resemble a footprint form previously linked to P. boisei, yet their dimensions exceed skeletal estimates for that species and are compatible with Homo erectus body size. The PNAS paper therefore keeps both possibilities open: unusually large P. boisei, or unexpectedly variable H. erectus. That ambiguity is scientifically productive because body fossils of P. boisei below the neck remain scarce. ([carta.anthropogeny.org][3])
GaJi10 also joins a growing East Turkana footprint record showing that different hominins repeatedly used lake-margin habitats. A 2024 study by members of the same team identified distinct footprint morphologies on contemporaneous surfaces, supporting ecological overlap between Homo erectus and P. boisei. Here, several similarly large individuals crossed the same surface within a narrow time window, consistent with group movement. But “mostly adult males” is an inference from estimated body size, not direct sexing, and one track surface cannot by itself establish a stable social system. ([PubMed][4])