A composite reconstruction of the earliest known Homo sapiens fossils from Jebel Irhoud (Morocco) based on micro computed tomographic scans of multiple original fossils
The first of our kind. A composite reconstruction of the earliest known Homo sapiens fossils from Jebel Irhoud (Morocco). (Picture credit: Philipp Gunz, MPI EVA Leipzig, License: CC-BY-SA 2.0)

Implications of the findings at Jebel Irhoud

Our understanding of the hominins from Jebel Irhoud has changed since that first discovery in 1961.

The findings from Jebel Irhoud have done much to change our perspectives on human evolution.

Early descriptions of these finds as Homo neanderthalensis were challenged by researchers, who claimed that the morphology was something closer to Homo sapiens (Hublin, 1992). More recent fossil finds from Jebel Irhoud, coupled with modern studies of their morphology have moved us away from the theory of an ‘African Neanderthal’ and suggest that the Jebel Irhoud hominins are early examples of Homo sapiens.

Face first?

Studies of juvenile fossil remains (Smith et al., 2007) established that these early modern humans had similar development rates to modern human children today. The dating of around 160,000 years meant that early modern humans were present in North Africa earlier than originally thought. Similarities to modern humans is suggested by the faces and teeth of these ancient fossils, though their braincase is still elongated and archaic (Hublin et al., 2017).

The picture emerging here suggests that early H. sapiens first developed modern human facial morphology, with the brain shape (and possibly brain function), evolving later in the H. sapiens lineage (Hublin et al., 2017).

Older than we thought

Then the 2017 thermoluminescence dating of the more recently discovered stone stools, along with new U-series and ESR dating of Irhoud 3, returned an age of around 300,000 years (Richter et al., 2017). Up to this point, it had been believed that H. sapiens had appeared on the scene around 200,000 years ago, in Eastern Africa. Jebel Irhoud has not only given that date a very significant push, but has also given us reason to question an exclusively East African origin for H. sapiens.

We’re still in Africa, of course, which supports the ‘Out of Africa’ theory. But an implication of these findings offers a more complex possibility that early H. sapiens was dispersed throughout the whole of Africa (Hublin et al., 2017).

At this stage of our study together during this course, it almost goes without saying that not all researchers agree with these conclusions. There is still some debate over Jebel Irhoud, with some researchers believing that these hominins should not be classified as Homo sapiens at all (Gibbons, 2017; Callaway, 2017).

The challenges of Jebel Irhoud have pushed our theories, our techniques and our modelling to new places. No doubt they will continue to do so for some time to come.

In this short video, Chris talks about the importance of the finds from Jebel Irhoud.

This is an additional video, hosted on YouTube.

Your task

How have the hominin fossils of Jebel Irhoud challenged you?

Do they change the way that you think about human evolution?

Please select the comments link and post your thoughts.

References

Callaway, E. (2017). Oldest Homo sapiens fossil claim rewrites our species’ history. Nature News.

Gibbons, A, (2017). World’s oldest Homo sapiens fossils found in Morocco. Science.

Hublin, J-J, (1992). Recent Human Evolution in Northwestern Africa. Philosophical Transactions: Biological Sciences, 337, 185-91.

Hublin, J.-J., Ben-Ncer, A., Bailey, S. E., Freidline, S. E., Neubauer, S., Skinner, M. M., Bergmann, I., Le Cabec, A., Benazzi, S., Harvati, K., and Gunz, P. (2017). New fossils from Jebel Irhoud (Morocco) and the Pan-African origin of Homo sapiens. Nature, 546, 289-292.

Richter, D., Grün, R., Joannes-Boyau, R., Steele, T.E., Amani, F., Rué, M., Fernandes, P., Raynal, J-P., Geraads, D., Ben-Ncer, A., Hublin, J-J. and McPherron, S.P. (2017). The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age. Nature, 546, 293-296.

Smith, T., Tafforeau, P., Reid, D.J., Grün, R., Eggins, S., Boutakiout, M. and Hublin, J-J. (2007). Earliest evidence of modern human life history in North African early Homo sapiens. Proceedings of the National Academy of Sciences of the United States of America, 104 (15), 6128-6133.

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This article is from the free online course:

A Question of Time: How We Date Human Evolution

Griffith University