PEOPLING

A Finger Bone Deep in Arabia

more than ~85,000 years ago

Palaeolithic · Middle Stone Age · Last glacial

A survey in the Nefud desert of Saudi Arabia, on the shore of a freshwater lake long since vanished, turned up a single human finger bone. Al Wusta-1, dated on the bone itself to at least 85,000 years, is the oldest directly dated fossil of our species outside Africa and the Levant. Its owner lived among a largely African fauna, in semi-arid grassland fed by monsoon rains, and lake beds nearby preserve human footprints from a still older wet phase, the last interglacial, some 120,000 years ago.

Why it matters

A bone the size of a thumb joint redrew the map of the human diaspora. On the older model, the first dispersals out of Africa reached no further than the Levant; Al Wusta puts people deep in the Arabian interior, following the rains into open grassland, tens of thousands of years before the later spread that carried our species across Eurasia. Arabia stops being a margin of that story and becomes one of its stages.

Dating & uncertainty

The bone itself was dated by uranium series, and a Bayesian model combining independent methods gives about 95,000 to 86,000 years. The Alathar footprints nearby are dated by luminescence to the last interglacial; tracks are not bones, so their attribution to our species is an argument rather than an identification, and their makers left no skeletons.

Sources

1. Groucutt et al. (2018), Nature Ecology & Evolution · Homo sapiens in Arabia by 85,000 years agodoi:10.1038/s41559-018-0518-2
2. Stewart et al. (2020), Science Advances · Human footprints provide snapshot of last interglacial ecology in the Arabian interiordoi:10.1126/sciadv.aba8940
3. Henry (2018), Nature Ecology & Evolution · Joining the dotsdoi:10.1038/s41559-018-0539-x

Our species’ history as one day

17:26:516 h 33 min before midnight

if the 315,000 years of Homo sapiens were compressed into a single day