Scientists just gave the middle finger to the idea that early humans migrated out of Africa in a single surge.
In work published April 9 in Nature Evolution and Ecology, a massive group of international researchers including scientists from the University of Cambridge, the Max Planck Institute, the Australian National University, and the Saudi Geological Survey reported finding an 88,000-year-old middle-finger bone in the Nefud desert in what is now Saudi Arabia.
For years, archaeologists assumed early humans migrated out of Africa in a straightforward path with several stops along the way. Genetic evidence found to date suggests that humans started relocating around 60,000 years ago, and moved in a single migration pattern only to the coastlines of the Mediterranean Sea. Now it seems that some early humans moved eastward, into the what is now the Gulf peninsula, while others traveled north along the coast.
The 88,000-year-old finger bone from the Nefud desert is the oldest Homo sapiens fossil ever found outside of Africa and the immediately adjacent eastern Mediterranean Levant. The researchers say the discovery suggests humans were moving in more sporadic patterns whenever they could. “This find, together with other finds in the last few years, suggest that modern humans, Homo sapiens, [were] moving out of Africa multiple times during many windows of opportunity during the last 100,000 years or so,” Michael Petraglia, an archaeologist from the Max Planck Institute in Germany and an author on the paper, said in a press conference.
The Nefud desert is dry and sandy today, but used to have water year-round through rivers and lakes. Grasses covered the land, and rivers helped support teeming wildlife including hippos, ostriches, and gazelles. Monsoon rain patterns likely helped make this land habitable, the study notes.
This is the latest discovery reminding us that we still don’t have a complete timeline of early human migration. For example, for years, we thought Homo sapiens evolved from Homo erectus in Africa 200,000 years ago—but then in 2017, scientists found bone evidence in Morocco suggesting humans may have been around as long as 300,000 years ago.
After discovering the bone in the Nefud desert, the team of researchers compared it to a library of finger bones from earlier species of human ancestors, and were able to determine that this particular bone belonged to a Homo sapien. Next, a group from the University of Cambridge used traces of radioactive uranium in the new middle-finger bone to approximate its age: roughly 88,000 years old.
This archeological upheaval of migration patterns wouldn’t have been possible if scientists hadn’t been permitted to explore the region, Petraglia told the New York Times (paywall). For decades, Saudi Arabia isolated itself from all sorts of foreign involvement in the country, including scientific research. Recently though, the country has started to open up to visiting scholars, even extending a free visa program to some applicants. Petraglia believes this will be just the first of many discoveries to be made in the region.