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The El Niño weather phenomenon of 1996-97 wrecked havoc on many parts of the world; however, it also enabled one team of scientists to make an incredible discovery. When the skies cleared and the floodwaters dried, a group of paleontologists in Ethiopia’s Afar region unearthed three human skulls as well as numerous other human bone fragments. After years of reconstruction and analysis, the remains were dated to approximately 160,000 years. The so-called ‘Herto skulls’ were thus older than the closest competitors by tens of thousands of years. Some experts believe they deserve their own subspecies classification: Homo sapien idaltu.
The Afar Research Site: Home of the Herto Skulls
The team consisted of researchers from the University of California, Berkley, and from the Ethiopian Rift Valley Research Service. The state of Afar is located in the northeastern corner of Ethiopia and stretches 27,820 square miles (72,053 km). Yet, the area the paleontologists have for years been particularly interested in is called the Afar Triangle (or Afar Depression), a geological depression caused at the junction of three diverging tectonic plates: the Nubian, Somalian, and Arabian. It is one of the lowest places in Africa and frequently holds the title of the hottest place on Earth. It also has the world’s largest lava lake formed by the most continuously active volcano, Erta Ale. The region is home to the Afar people, considered to be “the toughest people in the world” (Onuh, 2016)
From this region, one of the earliest known hominin fossils was discovered in 1974: a female Australopithecus afarensis known affectionately as Lucy. And here, in 1997, the Herto team discovered the oldest Homo sapien remains.
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Erta Ale is an active shield volcano located in the Afar Region of northeastern Ethiopia, within the Danakil Desert. ( CC BY-SA 2.0 ) Remains such as the skulls known as the ‘Herto fossils’ were discovered here.
The Serendipitous Discovery of the Skulls
In 1996-97, El Niño caused punishing rains to fall throughout much of Eastern Africa. The deluge caused many of the semi-Nomadic Afar people, including those of the Herto village, to abandon the Depression for higher ground. The rains caused a good deal of soil to wash into the Awash River, exposing numerous fossils. As a result of the people and herds moving to higher ground, these newly unearthed bones were not trampled and remained undamaged waiting to be discovered.
“When the scientists returned 11 days later, it took them only minutes to find the skulls of two adults, probably male. Six days after that, Dr. Berhane Asfaw of Ethiopia's Rift Valley Research Service found a third, the skull of a 6-or 7-year-old child, shattered into about 200 pieces. After years of painstaking cleaning, reassembly, and study, the team was confident enough to tell the world that it had found the earliest true Homo sapiens — older by at least 1,000 generations than anything previously discovered” (Lemonick and Dorfman, 2003).
Although the child’s skull appeared almost identical to modern human children skulls, the adults showed marked differences. “Each of the adult skulls was remarkably big. ‘We compared this with skulls of 6,000 modern humans, and still after that comparison not one was as big and robust as the Herto male,’ said Tim White, a University of California, Berkeley paleontologist and co-leader of the international team that found and studied the skulls. ‘These were very, very large robust people.’” (Joyce, 2003)
Nonetheless, the skulls are like modern humans in every feature. “The face is flat with prominent cheekbones, but without the protruding brow ridge of pre-human ancestors or Neanderthals. And the braincase is rounded, like a soccer ball, rather than the football shape of earlier human ancestors.” (Joyce, 2003) For this reason, the team proposed calling the remains a subspecies of humans Homo sapiens idaltu, ‘idaltu’ meaning ‘elder’ in Afar.
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A Herto skull, Homo sapiens idaltu. ()
Features of the Skulls
The similarity in features finally puts to rest the long-standing controversy over the origin of modern humans. While it is known that pre-human species left Africa and settled in Europe, the Middle East, and Asia, for decades it was not clear how these pre-human species all managed to develop into the same Homo sapien species. The answer is now clear that modern humans also developed in Africa and also left (most likely due to climate change). The second wave of African humanoids interbred and/or overtook the pre-human species, as can be seen in the well-studied case of the Neanderthals (one of the species that left Africa in the first wave).
“What this discovery in Ethiopia shows is that the shared features of modern humans - our high-rounded brain case, small brow ridges — originated in Africa,” said Chris Stringer from the Museum of Natural History in London” (Joyce, 2003).
Comparison of Modern Human and Neanderthal skulls from the Cleveland Museum of Natural History. ( CC BY-SA 2.0 )
A Post Mortem on the Ancient Skulls
Perhaps more interesting to the casual reader of paleo-discoveries was the treatment of the skulls immediately after their owners’ deaths 160,000 years ago. Each of the three intact skulls, as well as the (possibly) 10 skull fragments found at the Herto site, bore marks of deliberate tampering after death. Not in a cannibalistic way. Rather, the Herto fossils show the earliest known evidence of mortuary practices.
“Cut marks on the skulls indicate that the overlying skin, muscles, nerves and blood vessels were removed, probably with an obsidian flake. Then a stone tool was scraped back and forth, creating faint clusters of parallel lines. The modification of the child's skull is even more dramatic. The lower jaw was detached, and soft tissues at the base of the head were cut away, leaving fine, deep cut marks. Portions of the skull were smoothed and polished.” (Lemonick and Dorfman, 2003)
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Skull of the six to eight-year-old child, found in 1997, shows evidence of cut marks and polish after death. ( CC BY-SA 3.0 )
‘The cut marks aren't a classic sign of cannibalism,’ White said while showing the skulls to a TIME reporter in Addis Ababa. ‘If you wanted to get at the brain in order to eat it, you'd just smash open the skull.’ Instead, he suspects, the scratches might be a form of decoration. As for the polished areas, he says, ‘we know they weren't caused by the environment, because the marks go across the breaks between the recovered pieces. The child's skull looks as though it has been fondled repeatedly.’
‘This,’ concludes White, ‘is the earliest evidence of hominids continuing to handle skulls long after the individual died.’” (Lemonick and Dorfman, 2003)
Oldest Human Fossils Found
Oldest Human Fossils Found
A 160,000-year-old skull found in Ethiopia is the oldest known modern human fossil. Because the skull is slightly larger than those of modern-day humans, scientists have classified it as a subspecies -- Homo sapiens idaltu. David L. Brill/Brill Atlanta hide caption
An artist's reconstruction of an adult male Homo sapiens idaltu. J. Matternes hide caption
After six years of analysis, fossil hunters in Africa have confirmed the discovery of the oldest fossilized remains of modern humans yet found -- portions of skulls belonging to people who lived 160,000 years ago. Paleontologists say the discovery adds detail to a crucial period in human evolution, and confirms the hypothesis that modern humans evolved in Africa. NPR's Christopher Joyce reports.
A team led by University of California, Berkeley paleontologist Tim White found the fossils in desert sands near the Ethiopian village of Herto.
"These are the oldest fossils that we can confidently place in our own species, Homo sapiens ," says White.
The bones were uncovered in 1997, but it took six years to clean the pieces, glue them together and analyze their features. Because the fossils were in volcanic sediment, they could be reliably dated based on radioisotopes in the soil. White's team puts their age at 160,000 years. That beats the previous record for a human fossil by tens of thousands of years.
Two of the skulls from Herto belonged to adult males, and one to a child of six or seven. Each of the adult skulls was remarkably big.
"We compared this with skulls of 6,000 modern humans, and still after that comparison not one was as big and robust as the Herto male," says White. "These were very, very large robust people."
And yet they were also like modern-day humans in almost every feature. The face is flat with prominent cheekbones, but without the protruding brow ridge of pre-human ancestors or Neanderthals. And the braincase is rounded, like a soccer ball, rather than the football shape of earlier human ancestors.
There are other fossils of early humans almost as old. But they're only fragments, and the dating is unreliable -- a common problem in paleontology. But these skulls are almost complete, says Harvard paleontologist Daniel Lieberman, and that provides what paleontologists crave: certainty.
"What's really exciting about these fossils is that they are the best early modern humans we have ever found and the best dated -- this is just like nailing the coffin shut," says Lieberman. "We've got a good date now."
The fossils also confirm what genetic research has recently proposed: that modern humans evolved in Africa. There's little question that pre-human ancestors first appeared in Africa. Or that about 2 million years ago, they left Africa to populate parts of Asia, the Middle East and Europe. But some say primitive humans evolved into modern humans in many places around the world. Others, such as paleontologist Chris Stringer from the Museum of Natural History in London, say modern humans clearly evolved in in Africa.
"What this discovery in Ethiopia shows is that the shared features of modern humans -- our high-rounded brain case, small brow ridges -- originated in Africa," says Stringer.
Those first real humans, he says, most likely left Africa in a second wave that eventually replaced the remnants of the first, pre-human diaspora.
According to Berkeley's Tim White, the evidence also lays to rest any notion that Neanderthals were direct human ancestors. Rather, he says, they were a branch of pre-human evolution that remained isolated in Europe.
Jaw bone fossil discovered in Ethiopia is oldest known human lineage remains
A lower jaw bone and five teeth discovered on a hillside in Ethiopia are the oldest remains ever found that belong to the genus Homo, the lineage that ultimately led to modern humans.
Fossil hunters spotted the jaw poking out of a rocky slope in the dry and dusty Afar region of the country about 250 miles from Addis Ababa.
The US-led research team believes the individual lived about 2.8m years ago, when the now parched landscape was open grassland and shrubs nourished by tree-lined rivers and wetlands.
The remains are about 400,000 years older than fossils which had previously held the record as the earliest known specimens on the Homo lineage.
The discovery sheds light on a profoundly important but poorly understood period in human evolution that played out between two and three million years ago, when humans began the crucial transformation from ape-like animals into forms that used tools and eventually began to resemble modern humans.
“This is the the first inkling we have of that transition to modern behaviour. We were no longer solving problems with our bodies but with our brains,” said Brian Villmoare at the University of Nevada in Las Vegas.
The new fossil, found at a site called Ledi-Geraru, has a handful of primitive features in common with an ancient forerunner of modern humans called Australopithecus afarensis. The most well-known specimen, the 3m-year-old Lucy, was unearthed in 1974 in Hadar, only 40 miles from the Ledi-Geraru site. But the latest fossil has more modern traits too. Some are seen only on the Homo lineage, such as a shallower chin bone.
The picture that emerges from the fossil record is that 3m years ago, the ape-like Australopithecus afarensis died out and was superseded by two very different human forms. One, called Paranthropus, had a small brain, large teeth and strong jaw muscles for chewing its food. The other was the Homo lineage, which found itself with much larger brains, a solution that turned out to be more successful.
“By finding this jaw bone we’ve figured out where that trajectory started,” said Villamoare. “This is the first Homo. It marks in all likelihood a major adaptive transition.”
What drove Australopithecus to extinction and led to the rise of Homo is a mystery, but researchers suspect a dramatic change in the environment transformed the landscape of eastern Africa. “It could be that there was some sort of ecological shift and humans had to evolve or go extinct,” said Villmoare.
Other fossils recovered nearby the new human remains suggest that the region was much wetter than Hadar where Lucy was found. Remnants of antelopes, prehistoric elephants, primitive hippos, crocodiles and fish were all recovered from the Ledi-Geraru site, researchers said. Details of the discoveries are reported in two papers published in Science.
The human jaw was discovered in January 2013 by Chalachew Seyoum, an Ethiopian national on the team, and a student at Arizona State University. He was part of a group that had set off from camp that morning to look for fossils on a hill that was later found to be brimming with ancient bones.
Villamoare, who was on the expedition, recalled the moment of discovery. “I heard people yelling Brian! Brian! And I went round the corner and there was Chalachew. He recognised it, and said: ‘We’ve got a human.’ It had eroded out of the stratigraphy. It was in two pieces and was missing some of the teeth, but it was clearly of the genus Homo.”
The fossil bones are too fragmentary to give them a human species name. The jawbone could belong to Homo habilis, known as “handy man”, the earliest known species on the Homo lineage. But Villamoare is not convinced. It could be a new species that lived before Homo habilis.
Other researchers agree. In a separate paper published in Nature, Fred Spoor at University College, London, reports a virtual reconstruction of a Homo habilis skull. “By digitally exploring what Homo habilis really looked like, we could infer the nature of its ancestor, but no such fossils were known,” said Spoor. “Now the Ledi-Geraru jaw has turned up as if on request, suggesting a plausible evolutionary link between Australopithecus afarensis and Homo habilis.”
But until more remains are found, the mystery will remain. The US-led team has been back to the site this January to look for more fossils, but Villamoare said he cannot yet talk about what they did or did not find.
Skull of humankind's oldest-known ancestor discovered
The face of the oldest species that unambiguously sits on the human evolutionary tree has been revealed for the first time by the discovery of a 3.8 million-year-old skull in Ethiopia.
The fossil belongs to an ancient hominin, Australopithecus anamensis, believed to be the direct ancestor of the famous “Lucy” species, Australopithecus afarensis. It dates back to a time when our ancestors were emerging from the trees to walk on two legs, but still had distinctly ape-like protruding faces, powerful jaws and small brains, and is the oldest-known member of the Australopithecus group.
While Lucy became celebrated in studies of human evolution, her direct predecessor has remained a shadowy trace on the record, with only a handful of teeth, some limb bones and a few fragments of skull to provide clues about appearance and lifestyle.
The latest specimen, a remarkably complete adult male skull casually named MRD, changes this.
55m years ago
15m years ago
Hominidae (great apes) split off from the ancestors of the gibbon.
8m years ago
Chimp and human lineages diverge from that of gorillas.
4.4m years ago
Ardipithecus appears: an early "proto-human" with grasping feet.
4m years ago
Australopithecines appeared, with brains about the size of a chimpanzee’s.
2.3m years ago
Homo habilis first appeared in Africa.
1.85m years ago
First "modern" hand emerges.
1.6m years ago
Hand axes are a major technological innovation.
800,000 years ago
Evidence of use of fire and cooking.
700,000 years ago
Modern humans and Neanderthals split.
400,000 years ago
Neanderthals begin to spread across Europe and Asia.
300,000 years ago
200,000 years ago
60,000 years ago
Modern human migration from Africa that led to modern-day non-African populations.
“It is good to finally be able to put a face to the name,” said Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology, based in Germany, who is the co-author of an analysis of the find.
Prof Fred Spoor of the Natural History Museum, London, who was not involved in the research, said the discovery of MRD – and its dating to a period when the fossil record is very sparse – would substantially affect thinking on the evolutionary family tree of early hominins. “This cranium looks set to become another celebrated icon of human evolution,” he said.
The skull shows that MRD had a small brain – about a quarter of the size of a modern human – but was already losing some of its ape-like features. Its canines are smaller than those seen in even earlier fossils and it is already developing the powerful jaw and prominent cheekbones seen in Lucy and the famous Mrs Ples fossil (another later member of the Australopithecus group), which scientists think helped them chew tough food during dry seasons when less vegetation was available.
The 3.8m-year-old skull. Photograph: Michael Tewelde/AFP/Getty Images
The dating of the skull also reveals that Anamensis and its descendent species, Lucy, coexisted for a period of at least 100,000 years. This discovery challenges the long-held notion of linear evolution, in which one species disappears and is replaced by a new one. Anamensis, which now spans from 4.2 million to 3.8 million years ago, is still thought to be Lucy’s ancestor, but continued to hang around after the Lucy group branched off from the parent lineage. Geological evidence suggests the landscape would have featured extremely steep hills, volcanoes, lava flows and rifts that could easily have isolated populations, allowing them to diverge.
Divergent groups may have later crossed paths and competed for food and territory.
Yohannes Haile-Selassie, of the Cleveland Museum of Natural History and Case Western Reserve University, who led the research, said: “This is a game changer in our understanding of human evolution during the Pliocene.”
Afarensis, which continued to appear on the fossil record until at least 3 million years ago, has often been put forward as a likely candidate ultimately giving rise to the Homo lineage to which modern humans belong. But the discovery that multiple different lineages coexisted makes this hypothesis much less certain, according to the researchers.
“Having multiple candidate ancestral species in the right time and place makes it more challenging to determine which gave rise to Homo,” said Melillo.
Yohannes Haile-Selassie with the skull. Photograph: AFP/Getty Images
Spoor described Anamensis as the “oldest-known species that is unambiguously part of the human evolutionary tree”. Older fossils, like Ardi, which dates to 4.4 million years, are more contentious – some say it is on the human lineage, while others regard it as an extinct form of ape.
The first piece of the new fossil, the upper jaw, was found by a local worker in February 2016, in the Afar region of Ethiopia. “I couldn’t believe my eyes when I spotted the rest of the cranium. It was a eureka moment and a dream come true,” said Haile-Selassie.
Fossil pollen grains and chemical remains of fossil plant and algae taken from the sediment suggest that the individual lived by a river or along the shores of a lake surrounded by trees and shrubland.
The epic hominin trek
If the team is correct, the Apidima skull fragment adds to evidence that trickles of modern humans left Africa much earlier than previously believed. Until recently, it seemed as if modern humans took their time venturing out of the continent, with human populations today tracing their roots to a throng of H. sapiens that made the trek a mere 60,000 years ago.
By contrast, some ancient human cousins made it to central China as early as 2.1 million years ago, as evidenced by stone tools they left behind. The ancestors to the diminutive Homo floresiensis island hopped to Southeast Asia as early as 700,000 years ago. And Neanderthal predecessors headed into Europe as early as half a million years ago, splitting with their Denisovan relatives some 400,000 years ago.
This latest discovery suggests that modern humans made it much farther north than previously thought at a much earlier date, Harvati argues. But many other researchers believe that it’s too early to rewrite the history books.
“To make such a claim, you need a face,” Arsuaga says.
In a 2014 study, Arsuaga and his colleagues described 430,000-year-old crania from Spain’s Sima de los Huesos, or “pit of bones,” that had Neanderthal faces but lacked the telltale skull elongation. Perhaps the Apidima skull fragment similarly came from an early Neanderthal, he argues. The authors of the new study acknowledge that this might be the case, but they stress that the skull piece differs from the Sima remains, as well as from early Neanderthals of similar age to the Apidima fragment.
“As with any challenging new find, the appropriate initial reaction should be a healthy skepticism, even when my own name is on the paper,” Stringer says. “We don’t have the frontal bone, browridge, face, teeth, or chin region, any of which could have been less ‘modern’ in form.” Still, he emphasizes the many measures the team took to reduce any uncertainties.
“Reconstructions are sort of art-meets-science,” says Christopher Walker, a biological anthropologist at North Carolina State University. While such analyses can be swayed by expectations and model skulls used for comparison, he says that the team was thorough, and he agrees that the skull fragment is “really a mixed bag of Homo sapiens-like features.”
But Warren Sharp of the Berkeley Geochronology Center disagrees with the fragment’s early date, calling the team’s data for that result “imprecise and highly scattered.” Sharp also worries about the dating of the next oldest H. sapiens remains found in Israel, contending that the fossil can’t be older than 70,000 years.
“We give all the details in the paper,” Grün counters. “There’s nothing we swept under the carpet, and this, in my view, is the best interpretation of the results.”
Whether or not H. sapiens made it to Greece 210,000 years ago, the early excursion didn’t seem to stick, and these adventurers likely died out without leaving genetic traces in humans today. Clues to the enigmatic populations, however, may still linger in hints of H. sapiens-like DNA found in Neanderthals—the result of a proposed early phase of interbreeding between the two groups hundreds of thousands of years back.
Perhaps the Apidima fossils belonged to a population that met and interbred with our Neanderthals cousins, says Harvati. But without more evidence, it’s tough to say where this population ranged, or how long they persisted.
“We have a quick snapshot,” Delson says. “This certainly tells us that it’s worth looking elsewhere.”
The Skull of Humanity's Oldest Known Ancestor Is Changing Evolutionary Beliefs
The hominin known as Lucy may not be the direct ancestor of humans.
The skull of the species Australopithecus anamensis, a fossil discovered in 2016 in Ethiopia, is seen in this photo released on August 28, 2019, in Cleveland, Ohio, US. Photo: Dale Omori/Cleveland Museum of Natural History/Handout via Reuters
The recent discovery of a 3.8m-year-old cranium (skull without the lower jaw) is the hottest topic of conversation among palaeoanthropologists right now. But fossils are found all the time, so why is the cranium of this small, old man so important? It turns out the discovery is changing our view of how early hominin species evolved – and how they led to humans. To understand how, let’s start at the beginning.
In 1995, researchers found several partial jaws, isolated teeth and limb bones in Kenya, dated between 4.2m and 3.9m years old, and assigned them to a brand new species: Australopithecus anamensis. All these fossils were found in sediments associated with an ancient lake – “anam”, which means lake in the local language. A number of additional specimens were then found in Ethiopia, thought to belong to the same species.
The primitive features of A. anamensis have led to the widespread view that this species is the ancestor of Australopithecus afarensis, a younger hominin from Tanzania, Ethiopia and perhaps Kenya, dated between 3.8m and 3m years old. The most iconic fossil of A. afarensis is probably the partial skeleton known as Lucy, which was for a long time viewed as the oldest known human ancestor.
Anagenesis vs cladogenesis. Photo: Author provided
The newly discovered cranium, nicknamed “MRD” after its collection number MRD-VP-1/1, shows many similarities to the already existing A. anamensis specimens, and was therefore assigned to this species.
However, the MRD cranium was intact enough to allow scientists to analyse for the first time the complete face and braincase, and examine parts of the cranium that were still missing in the fossil record of A. anamensis.
The authors discovered several new morphological features in the MRD cranium that are conventionally considered to be characteristic of younger species on the human lineage.
The depth of the palate, for example, exceeds that of all known A. anamensis and A. afarensis specimens, and even is among the deepest palates of later Australopithecus species. This challenges the long and widely-held view that Lucy’s species evolved gradually from A. anamensis without branching of the evolutionary line – a process known as anagenesis.
A facial reconstruction by John Gurche of the species Australopithecus anamensis, based on a nearly complete cranium fossil discovered in 2016 in Ethiopia, is seen in this photo released on August 28, 2019, in Cleveland, Ohio, US. Photo: Matt Crow/Cleveland Museum of Natural History/Handout via Reuters
Since these modern features were already present in the older species, the most likely scenario is that Lucy’s species formed by evolutionary divergence from A. anamensis – a process known as cladogenesis.
It is not known though exactly when A. afarensis diverged. Further evidence for cladogenesis comes from a 3.9m years old frontal bone (part of the forehead) from Ethiopia, discovered in 1981. Its shape is different from MRD which suggests this fossil probably belongs to A. afarensis.
If that is the case, then we need to revise the human evolutionary timeline, with A. anamensis existing from 4.2m to 3.8m years ago, and A. afarensis from 3.9m to 3m years ago. This would imply that both species were overlapping for at least 100,000 years, making it impossible for A. afarensis to have evolved gradually from one single ancestral group. In fact, it is becoming increasingly obvious that most species on our evolutionary lineage likely evolved by branching off from existing groups.
A fossil of Lucy’s ancestor, 3.8 million years old cranium of Australopithecus Anamensis which was discovered in Waranso-Mile paleontological site, Afar region in Ethiopia is seen at the National Museum in Addis Ababa, Ethiopia August 28, 2019. Photo: Reuters/Tiksa Negeri
The human line
The new discovery also challenges the idea of Lucy’s species being the ancestor of all later Australopithecus hominins, which eventually led to humans.
A vertically straight and steeply rising curvature of the cheekbone has traditionally been considered to be a relatively modern feature. It was present in Australopithecus africanus (3.7m-2.1m years ago from southern Africa, considered by some to be a direct ancestor of the Homo lineage) and in Paranthropus (2.7m-1.2m years ago from southern and eastern Africa, not directly on our evolutionary line).
The opposite condition – a low and arched cheekbone – is considered to be primitive, and is shared among A. afarensis, Ardipithecus ramidus (4.3m-4.5m years ago from Ethiopia, a more ape-like primitive hominin) and African apes.
The crest of the MRD cranium, which is surprisingly modern, now challenges this view. It further opens up the possibility that the longstanding idea of A. afarensis as the ancestor of all later Australopithecus groups might have been wrong, and that instead A. anamensis is the ancestor to these younger species. Which early hominin is the direct ancestor of humans still remains an unanswered question.
Clearly this latest discovery has given new insights into our evolutionary past, but also increased the complexity of the relationships between early hominins. The mid Pliocene (5.3m-2.6m years ago) has become crowded with multiple, contemporary and geographically widespread species.
A facial reconstruction by John Gurche of the species Australopithecus anamensis, based on a nearly complete cranium fossil discovered in 2016 in Ethiopia, is seen in this photo released on August 28, 2019, in Cleveland, Ohio, US. Photo: Matt Crow/Cleveland Museum of Natural History/Handout via Reuters
Clarifying the relationships between these species, confidently characterising their morphology, and deciphering the complex and intricate story about hominin evolution is not a simple task. Specimens at each new site capture a different point along the evolutionary trajectory, but it is not easy to convert these findings into stable and reliable branches on an evolutionary tree.
More specimens from time periods and geographical locations that are currently underrepresented in the fossil record could help to settle these questions, but could equally turn everything we know upside down.
Discoveries all over the world in the last decade have led to a complete rethinking of our evolutionary past. It shows that new fossils do not always support existing hypotheses, and that we must be prepared to change our views and formulate new theories based on the evidence at hand.
Hester Hanegraef is a PhD Candidate of Anthropology at the Natural History Museum
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The skull, known as "MRD", was discovered not far from the younger Lucy -- the ancient ancestor of modern humans
Addis Ababa (AFP) - A "remarkably complete" 3.8-million-year-old skull of an early human has been unearthed in Ethiopia, scientists announced Wednesday, a discovery that has the potential to alter our understanding of human evolution.
The skull, known as "MRD", was discovered not far from the younger Lucy -- the ancient ancestor of modern humans -- and shows that the two species may have co-existed for about 100,000 years.
"This skull is one of the most complete fossils of hominids more than 3 million years old," said Yohannes Haile-Selassie, the renowned Ethiopian paleoanthropologist of the Cleveland Museum of Natural History who is a co-author of two studies published Wednesday in the journal Nature.
It "looks set to become another celebrated icon of human evolution," joining the ranks of other high-profile hominid findings, Fred Spoor of the Natural History Museum of London wrote in a commentary accompanying the studies.
"Toumai" (of the species Sahelanthropus tchadensis) is around 7 million years old and is considered by some paleontologists to be the first representative of the human lineage. It was discovered in Chad in 2001.
Ardi (for Ardipithecus ramidus, another species of hominid) was found in Ethiopia in 1994 and is believed to be around 4.5 million years old.
And Lucy, the famous Australopithecus afarensis, was discovered in Ethiopia in 1974 and is 3.2 million years old.
Australopithecus afarensis is one of the longest-lived and most studied early human species.
The new skull, MRD, belongs to the species Australopithecus anamensis.
Discovered in February 2016 at the site of Woranso-Mille, just 55 kilometres (34 miles) from where Lucy was found in the Afar region of northeastern Ethiopia, MRD offers "the first glimpse of the face of Lucy's ancestor," according to a statement announcing the finding.
Other lesser-known Australopithecus fossils date back at least 3.9 million years, but they featured only jaws and teeth. Without the skull, scientists' understanding of the evolution of these extinct hominids has remained limited.
The finding challenges a previously held belief about how humans evolved.
"We thought A. anamensis (MRD) was gradually turning into A. afarensis (Lucy) over time," said Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology in Germany, a co-author of the Nature studies.
But MRD reveals that the two species co-existed for about 100,000 years, the scientists said.
"This is a game changer in our understanding of human evolution during the Pliocene," Haile-Selassie said.
Melillo agreed, saying it also raised new questions like whether the species competed for space or food.
Though small, the skull has been determined to be that of an adult. Facial reconstructions show a hominid with cheekbones projected forward, a prominent jaw, a flat nose and a narrow forehead.
To the researchers' surprise, the skull represents a mixture of characteristics of Sahelanthropus like "Toumai" and Ardipithecus like "Ardi" as well as more recent species.
"Until now, there was a big gap between the oldest human ancestors, which are about 6 million years old, and species like 'Lucy', which are two to three million years old," said Melillo. But MRD "links the morphological space between these two groups," she added.
At a press conference in Addis Ababa on Wednesday, Haile-Selassie described how Ali Bereino, a "local guy" from Afar, found the jaw of MRD and immediately brought it to Haile-Selassie's attention.
The cranium was soon found nearby, and workers spent days sifting through earth that was "1 percent dirt and 99 percent goat poop", Haile-Selassie said.
"People were not disgusted by it. but some of them of course had to cover their faces because the smell was so bad," he said.
It was a small price to pay for the discovery of such a complete specimen, he said.
"I did not believe my eyes when I saw the rest of the skull," recalled Haile-Selassie, who described the discovery as "a eureka moment and a dream come true".
Newly Found Skull In Ethiopia Provides Link To Evolutionby Abraham
A “remarkably complete” 3.8-million-year-old skull of an early human has been unearthed in Ethiopia, scientists announced Wednesday, a discovery that has the potential to alter our understanding of human evolution.
The skull, known as “MRD”, was discovered not far from the younger Lucy — the ancient ancestor of modern humans — and shows that the two species may have co-existed for about 100,000 years.
“This skull is one of the most complete fossils of hominids more than 3 million years old,” said Yohannes Haile-Selassie, the renowned Ethiopian paleoanthropologist of the Cleveland Museum of Natural History who is a co-author of two studies published Wednesday in the journal Nature.
It “looks set to become another celebrated icon of human evolution,” joining the ranks of other high-profile hominid findings, Fred Spoor of the Natural History Museum of London wrote in a commentary accompanying the studies.
A Serendipitous Skull Discovery in Ethiopia: Is This the Oldest Known Modern Man? - History
They are described as the oldest known fossils of modern humans, or Homo sapiens .
What excites scientists so much is that the specimens fit neatly with the genetic studies that have suggested this time and part of Africa for the emergence of mankind.
"All the genetics have pointed to a geologically recent origin for humans in Africa - and now we have the fossils," said Professor Tim White, one of the co-leaders on the research team that found the skulls.
"These specimens are critical because they bridge the gap between the earlier more archaic forms in Africa and the fully modern humans that we see 100,000 years ago," the University of California at Berkeley, US, paleoanthropologist told BBC News Online.
The skulls are not an exact match to those of people living today they are slightly larger, longer and have more pronounced brow ridges.
The Herto discoveries were hailed on Wednesday by those researchers who have championed the idea that all humans living today come from a population that emerged from Africa within the last 200,000 years.
The proponents of the so-called Out of Africa hypothesis think this late migration of humans supplanted all other human-like species alive around the world at the time - such as the Neanderthals in Europe.
If modern features already existed in Africa 160,000 years ago, they argued, we could not have descended from species like Neanderthals.
"These skulls are fantastic evidence in support of the Out of Africa idea," Professor Chris Stringer, from London's Natural History Museum, told BBC News Online.
The skulls were found in fragments, at a fossil-rich site first identified in 1997, in a dry and dusty valley.
Stone tools and the fossil skull of a butchered hippo were the first artefacts to be picked up. Buffalo fossils were later recovered indicating the ancient humans had a meat-rich diet.
The most complete of the adult skulls was seen protruding from the ancient sediment it had been exposed by heavy rains and partially trampled by herds of cows.
The skull of the child - probably aged six or seven - had been shattered into more than 200 pieces and had to be painstakingly reconstructed.
All the skulls had cut marks indicating they had been de-fleshed in some kind of mortuary practice. The polishing on the skulls, however, suggests this was not simple cannibalism but more probably some kind of ritualistic behaviour.
This type of practice has been recorded in more modern societies, including some in New Guinea, in which the skulls of ancestors are preserved and worshipped.
The Herto skulls may therefore mark the earliest known example of conceptual thinking - the sophisticated behaviour that sets us apart from all other animals.