A 1.5 million year old fossil is rewriting the “Out of Africa” theory once again, as vertebrae unearthed in Ubeidiya, Israel appear to show that individuals from a pre-human species came in one of multiple waves out of the vast continent.
The history of humanity involves many migrations out of Africa, made for different reasons, with varying levels of evolution evident in each group. Scientists now believe that there were multiple migrations out of the continent before modern Homo sapiens migrated out approximately 270,000 years ago, mixing with Neanderthals who were already living in Europe and Asia, along with Denisovans.
Individuals from human species that are now extinct have been shown to have migrated from Africa to Eurasia by at least 1.8 million years ago, during the early Pleistocene era, which was from 2.6 million to 11,700 years ago.
This vast time period encompasses the last Ice Age, which involved such large amounts of seawater being taken up as ice that there were land bridges between what is now Siberia and Alaska and the European continent and the UK.
1.5 million year old fossil is oldest evidence of ancient humans in Israel
Although modern humans are now the only surviving members of our long human lineage, other human species traveled far and wide, exploring most of the continents of the Earth far back into antiquity.
The newly analyzed vertebra from an unknown human species that was unearthed in Israel at a site that is known to be the second-oldest archaeological site outside Africa reinforces the theory that there were indeed multiple waves of humanity coming out of Africa for millions of years.
Dated back to approximately 1.5 million years, the vertebra found at ‘Ubeidiya, located in the Jordan Valley, is the oldest evidence ever found of any ancient humans in Israel, according to Alon Barash, a paleoanthropologist and human anatomist at Bar-Ilan University in Israel.
In an interview with Live Science, Barash, who published his findings earlier in February in the journal Scientific Reports, said that the site has brought to light not only ancient stone artifacts resembling those found in East Africa but an array of animal bones belonging to extinct species such as saber-toothed cats and mammoths as well.
Back in 2018, the scientists reexamined a vertebra from the lower back of a hominin, the group that includes humans, who as our ancestors are our closest evolutionary forebears. The bones, which were initially unearthed in ‘Ubeidiya in 1966, underwent a sophisticated new analysis that allowed them to pinpoint their exact age.
John Hawks, a paleoanthropologist at the University of Wisconsin-Madison who was not involved with the study, told interviewers from Live Science “It’s great to see new discoveries coming from old collections like this one. It shows that there is always something left to find even when archaeologists think they’ve done it all.”
1.5 million year old fossil of vertebra from an extinct species of human
Although there isn’t enough data from this one bone to show definitively that it belonged to any known species of extinct human, after the researchers compared the vertebra with those from animals, including bears, hyenas, hippos, rhinos, horses, gorillas and chimpanzees, who all lived in the area at one time, the team concluded that the it came from an extinct species of human being.
Intriguingly, although the scientists say that, given the bone’s size, shape and other properties, the researchers estimated it was from a child aged from 6 to 12 years, but he or she would have been about 5 feet, 1 inch (155 centimeters) tall, weighing about 100 to 110 pounds (45 to 50 kilograms). Since this is the size of an average 11- to 15-year-old modern human, this means the child would have towered over his modern human contemporaries.
In other words, this child would have been head and shoulders taller than its modern counterparts.
“The study shows how much information about an ancient individual we can get from a small piece of the anatomy,” Hawks noted.
This finding alone stands much of previous study about human ancestors on its head, with most of those species being of diminutive size until relatively recently in human history.
The approximately 1.8 million-year-old human fossils that were unearthed in Dmanisi, Georgia, suggested the extinct humans whose remains were found there were of small stature, standing from 4 feet, 9 inches to 5 feet, 5 inches (145 to 166 cm) and weighing 88 to 110 pounds (40 to 50 kg) as adults.
Individual at ‘Ubeidiya had size, power of some modern athletes
The Israeli scientists analyzing the vertebra found at ‘Ubeidiya believe that in adulthood, that individual may have outstripped the majority of modern humans in size and heft, growing to reach 6 feet, 6 inches (198 cm) in height and weighing 220 pounds (100 kg).
“Dmanisi hominins are small in body size — at the smallest end of human variation across populations today,” Hawks explained, adding “This new vertebral body suggests a large body size, like some of those seen in Africa at around the same time.”
The scientists say that the findings show that the 1.8 million-year-old fossils from Dmanisi and the 1.5 million-year-old vertebra in ‘Ubeidiya are evidence of two different kinds of hominins. That means ancient humans most likely left Africa in multiple waves.
“We can securely talk about two early Pleistocene out-of-Africa migration waves,” Barash noted in the interview.
There are other differences found among the artifacts at both sites, the researchers say, adding to the pile of evidence that these peoples belonged to different human groups. The types of stone tools found in Dmanisi, which are known as Oldowan, were quite basic, usually created from just one or a few flakes chipped, or knapped, off one stone by another.
But the Israeli stone tools, which were of the early Acheulean type, were more complex, including hand axes made from volcanic rock, Live Science reports.
And contrary to their current climates, Dmanisi was drier and savannah-like, and ‘Ubeidiya was at that time warmer and more humid, even part of a woodland forest climate, leading the peoples who lived at those sites to develop different tools in adapting to their different needs.
But the sheer size of this individual whose vertebra was found at ‘Ubeidiya may pose a problem in itself, leading to some speculation that he or she may have suffered from some kind of medical problem.
Naturally, this would skew findings related to the size of different hominid populations, making it “very risky to use as the representative for an entire species,” says Marc Meyer, a paleoanthropologist at Chaffey College in Rancho Cucamonga, California, who was not involved in the study.
Even older stone tools found in Jordan, Pakistan, China
“Assuming that it is a hominin, what is mind-blowing is that the ‘Ubeidiya fossil is developmentally like a 5-year-old but is significantly larger than our team’s entire sample of fossil Homo and juvenile humans up to age 17,” he adds.
“In fact, it’s the size of very large individuals such as Neanderthals or gorillas. To have a 5-year-old child as large as an adult gorilla is just wild.”
Hawks says that this may be just another example of natural human genetic variations. “Humans have changed in body size many times in our evolution, and both large-bodied and small-bodied human populations today have emerged over thousands of years, which is a short time compared to the hundreds of thousands of years here,” he said.
And that in itself is not evidence that this ‘Ubeidiya group was of another lineage than that in Georgia.
“I think it’s likely that humans or other hominins were in Eurasia much earlier than Dmanisi,” Hawks said, adding “There are a few sites that seem to have older stone tool evidence, in Jordan, China and Pakistan.”
Barash states that despite these spectacular findings, showing the oldest evidence ever found of any ancient humans in Israel, “we need to continue excavation in ‘Ubeidiya — who knows what bones are waiting to be discovered.”