Oldest Homo sapiens bones ever found shake foundations of the human story
Fossils recovered from an old mine on a desolate mountain in Morocco have rocked one of the most enduring foundations of the human story. They go directly against the theory that Homo sapiens arose in a cradle of humankind in East Africa 200,000 years ago.
Archaeologists unearthed the bones of at least five people at Jebel Irhoud, a former mine 62 miles (100 km) west of Marrakesh in North Africa. The researchers were stunned when dating tests revealed that a tooth and stone tools found with the bones were about 300,000 years old.
“My reaction was a big ‘wow,’” said Jean-Jacques Hublin, a senior scientist on the team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “I was expecting them to be old, but not that old.”
Oldest Known Specimens Of Modern Humans
Hublin said the extreme age of the bones makes them the oldest known specimens of modern humans. They pose a major challenge to the idea that the earliest members of our species evolved in East Africa 100,000 years later.
“This gives us a completely different picture of the evolution of our species," Hublin said. He added that not only are the fossils much older but that it makes researchers think humans were all over the African continent by that time.
Tools First Thought To Be Only 40,000 Years Old
Jebel Irhoud has thrown up puzzles for scientists since fossilized bones were first found at the site in the 1960s. At first, tools found there were thought to belong to Neanderthals and to be only 40,000 years old. Neanderthals are considered a sister group that lived alongside, and even bred with, our modern human ancestors.
In fresh excavations at the Jebel Irhoud site, Hublin and others found more remains. Alongside the bones, the researchers found tools, gazelle bones and other leftovers of human life.
African Origin For Modern Humans
Scientists have long looked to East Africa as the birthplace of modern humans. Until the latest findings from Jebel Irhoud, the oldest known remnants of our species were found at Omo Kibish in Ethiopia and dated to be 195,000 years old. Other fossils and genetic evidence all point to an African origin for modern humans.
In the first of two papers published in the scientific journal Nature last Wednesday, the researchers describe how the newly discovered fossils look most like modern humans. The part of the skull that held the brain, however, was much longer. This suggests that the modern human brain developed in Homo sapiens alone.
Apart from being more stout and muscular, the adults at Jebel Irhoud looked similar to people alive today.
The remains of more individuals may yet be found at the site. What they were doing there, however, is unclear. Studies of the flint tools show that the stones came not from the local area, but from a region about 30 miles south of Jebel Irhoud.
Hublin concedes that scientists have too few fossils to know whether modern humans had spread to the four corners of Africa 300,000 years ago. They are guessing based on a 260,000-year-old skull found in Florisbad in South Africa.
He finds the theory compelling, however. The main idea is that early humans traveled all around the continent, and so different parts of Africa led to the beginning of modern humanity.
Human Body Developed Quickly
John McNabb, an archaeologist at the University of Southampton, said that the fossils suggest an answer to the question of how fast the modern human body developed. He said the fossils make it seem like the human body developed quickly.
“There are some intriguing possibilities here, too," he added. Before, the tools the archaeologists discovered were not thought to be that old. McNabb wondered if the tools are connected to the development of the beginning of humans.
Lee Berger, whose team recently discovered the 300,000-year-old ancient human relative outside Johannesburg in South Africa, said dating the Jebel Irhoud bones was thrilling. He is unconvinced, however, that modern humans lived all over Africa so long ago. “They’ve taken two data points and not drawn a line between them, but a giant map of Africa,” he said.
Another archaeologist from Stony Brook University in New York, John Shea, added that people should be cautious when people say they have found the oldest of anything. Stone tools can move around and settle in rock layers of different ages.
Shea was also uneasy with the scientists combining fossils from different individuals. He also did not like them comparing reconstructions of complete skulls from fragmentary remains. “Such ‘chimeras’ can look very different from the individuals on which they are based,” he said.
“For me, claiming these remains are Homo sapiens stretches the meaning of that term a bit,” Shea added. He said that structurally, ancient human species look pretty different.
Rarest Of The Rare
Jessica Thompson, however, an anthropologist at Emory University in Atlanta, said the new results show just how incredible the Jebel Irhoud site is. “These fossils are the rarest of the rare because the human fossil record from this time period in Africa is so poorly represented. They give us a direct look at what early members of our species looked like, as well as their behavior," she said.
She thinks the faces are definitely human. “It really does look like in Africa especially, but also globally, our evolution was characterized by numerous different species all living at the same time and possibly even in the same places.”