180 000 year-old jawbone places humans outside Africa far earlier than thought

The narrative, that early modern humans originated in Africa and dispersed into Eurasia around 60 000 years ago where they quickly took over territory from the Neanderthals and others they may have found, has been accepted for decades. But recent discoveries are muddying the waters a little: a trove of teeth dating from around 100 000 years ago were found in a Chinese cave and now this latest find adds another dimension to our earliest history.

An international research team recently reported their discovery in the journal ‘Science’. The remains, a piece of maxilla and associated dentition of an adult specimen whose morphology and features are similar to those usually observed in Homo sapiens, were found at the Misliya cave site in northern Israel. Prof. Israel Hershkovitz, who led the work at Tel Aviv University, explains this is a revolution in the way we understand the evolution of our own species.

Aspects of the dating study were funded by an EU fellowship through the HR_ESR project. The age of the fossil was securely obtained through a combination of different dating methods that provided consistent results. These show an age range of between 177 000 and 194 000 years, pushing the earliest evidence of modern humans outside Africa back by approximately 50 000 years. Dr Mathieu Duval, supported by HR_ESR, worked with colleagues to contribute to the direct dating of a tooth collected from the maxilla. They used a combination of methods called uranium-series and Electron Spin Resonance, following the most advanced analytical procedure in order to ensure a minimum destruction of the remains.

Misliya breaks the mould

The discovery has, unsurprisingly, generated a lot of fascination amongst experts in the field. It is being suggested that the find points at multiple waves of migration across Europe and Asia and could also mean that modern humans in the Middle East were mingling, and possibly mating, with other human species for tens of thousands of years. The earliest hominins lived around 6-7 million years ago in Africa. These early evolutionary ancestors are recognised as belonging to the human family mainly because their bones reveal clear signs of bipedalism. It was not until around 2 million years ago that human ancestors first migrated out of Africa and spread throughout the Old World.

Advanced stone tools and blades discovered in the surroundings suggest the cave’s inhabitants were well-equipped hunters, who used sling projectiles and elegantly carved blades to kill and butcher gazelles, oryx, wild boars, hares, turtles and ostrich. Researchers also discovered evidence of matting made from plants. Radioactive dating also dates the tools to between 131 000 and 221 000 years old, which is consistent with the ESR results from the fossil tooth.

The EU helping to develop methods needed to date the earliest finds

Electron Spin Resonance (ESR) is probably the only chronometric method that can be used to date Early Pleistocene fossil teeth from early hominid occupations in the Mediterranean area. But the standard procedure has been shown to have some limitations. The recent HR_ESR (Developing High Resolution Electron Spin Resonance (ESR) dating of fossil teeth: contribution to the chronology of early hominid occupations in the Mediterranean area) project took a two-pronged approach to improving the method of dating.

They investigated the physical and chemical processes that affect dental tissues at micro scale and evaluated their impact on the ESR age results, while also developing a high resolution combined Uranium Series-ESR dating approach for fossil teeth. The same approach was recently used to directly date the fossil teeth from the newly discovered Homo naledi species, dating work also funded by HR_ESR.

For more information, please see:
CORDIS Project web page
3D reconstruction of oldest modern human fossil found outside Africa