PEOPLING

Jebel Irhoud: Oldest Homo sapiens

~315,000 years ago

Palaeolithic · Middle Stone Age · MIS 9

At Jebel Irhoud, in Morocco, fossils about 315,000 years old are the oldest attributed to the Homo sapiens lineage.

Jebel Irhoud is a palaeontological site in Morocco, brought to light during the working of a barite mine from 1960 onwards and re-excavated in a programme whose results were published in 2017. It has yielded the remains of at least five individuals, attributed to the early stages of the Homo sapiens lineage, associated in the same levels with Middle Stone Age flints, the technical tradition of Africa in that period. Several of these flints had been heated in fires, which makes them datable: heat resets the clock that natural radioactivity maintains within the crystal, and the energy accumulated since is released as light when the stone is heated again in the laboratory. The site is placed in this way at about 315,000 years. The face, jaw and dentition of the fossils show modern characters, while the braincase retains an elongated, more archaic form.

Why it matters

The location of the site has fed the discussion of how the species came into being. Morocco lies some four thousand kilometres from the East African sites that previously held the oldest fossils attributed to Homo sapiens, and the same technical tradition links the two ends of the continent. Several authors conclude from this that the emergence took place at a continental scale, involving populations that met and parted over time, rather than in a single region. All present-day human populations descend from that African network.

Dating & uncertainty

The age, obtained by thermoluminescence, is 315,000 ± 34,000 years. What that date dates is debated separately from the measurement itself: the fossils combine a modern-type face with an elongated braincase, and the literature accordingly speaks of the early stages of the H. sapiens clade rather than of an appearance. It follows that the date assigned to the origin of the species varies by a hundred thousand years or more depending on where the species boundary is drawn.

Our species’ history as one day

00:00:0024 h before midnight

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