That’s not unexpected, though. Many lines of evidence show that early humans probably dispersed from Africa on several occasions, encountering other hominids like Neanderthals and Denisovans who had already established themselves in the wider world. These groups all had sex, leaving traces of their DNA in each other’s genomes. And based on these exchanges, geneticists have estimated that some humans must have been living beyond Africa by 220,000 years ago or more. If that’s the case, there must have been fossils outside the continent that were older than the Skhul specimens. It was just a matter of finding them.
“The Misliya fossil is significant because it is the first finding that conclusively shows that early modern-human population expansions out of Africa actually did occur even before the Skhul episode,” says Katerina Harvati, from the University of Tübingen.
Once Hershkovitz and Weinstein-Evron discovered the jawbone, they had two challenges. First, they had to identify it. Several other hominids, like Neanderthals, were living in the same region at the time, but the team determined that the jaw and teeth had none of the characteristic traits of these other groups. Instead, its features were clearly those of modern humans. “It is Homo sapiens par excellence,” says Hershkovitz. “It’s a modern human, like you or me, more or less.”
Next, the team had to date the specimen. They used three techniques, each performed by different labs working independently in separate countries. An Australian team analyzed burned flint tools that were found near the fossils, concluding that they are 179,000 years old. An Israeli team measured radioactive isotopes of uranium in the rocky sediment attached to the teeth, estimating that the fossil's minimum age is somewhere between 177,000 and 193,000 old. And a Spanish team analyzed the enamel on one of the teeth, showing that it has a maximum age of 194,000 years.
“Each lab did a different analysis without knowing the results of the other labs,” says Hershkovitz. “Amazingly, they all came more or less with the same numbers. The dates are more secure than for any other fossil I know of.”
These dates don’t imply that humans have lived continuously in the Levant for at least 180,000 years, or that the Misliya residents were the direct ancestors of those who eventually lived in Skhul. At the time, the region had a variable climate, with humid phases punctuated by droughts. Rather than being a permanent sanctuary for migrating humans, it could have been what some anthropologists have called a “boulevard of broken dreams”—a place where humans regularly ventured into, but rarely stayed permanently. The Misliya jaw simply suggests when those migration attempts might have begun.
“The research is solid,” says Shara Bailey from New York University, who specializes in ancient hominin teeth. “Is it the earliest modern human outside of Africa? I think that’s probably true. But it’s perhaps unsurprising, given that we now know that Homo sapiens was in Africa even earlier than we had thought.”