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Researchers studying ‘Turkana Boy’, a well preserved 1.5 million-year-old child or adolescent from the Homo erectus species, have discovered that he may not have had a congenital bone disorder such as dwarfism or scoliosis, as previously believed.
Until now, Turkano boy was not considered as representative of his species as it was always thought that the strange formation of his spine was pathological. However, the new analysis published in the American Journal of Physical Anthropology, has revealed that Turkano boy did not have any genetic bone problems, only a herniated disc in his back.
The implication is that Turkano boy can be studied in a new light – conclusions about the Homo erectus’ anatomy can now be made based on his skeleton.
You can read more here.
3.6-million-year-old human skeleton found, shocking scientists
The virtually complete Australopithecus fossil "Little Foot" is displayed at the University of the Witwatersrand in Johannesburg, South Africa, Wednesday, Dec. 6, 2017. Researchers in South Africa have unveiled what they call "by far the most complete skeleton of a human ancestor older than 1.5 million years ever found." (AP Photo/Themba Hadebe)
JOHANNESBURG (AP) — Researchers in South Africa have unveiled what they call “by far the most complete skeleton of a human ancestor older than 1.5 million years ever found.”
The University of the Witwatersrand displayed the virtually complete Australopithecus fossil on Wednesday.
The skeleton dates back 3.6 million years. Its discovery is expected to help researchers better understand the human ancestor’s appearance and movement. The researchers say it has taken 20 years to excavate, clean, reconstruct and analyse the fragile skeleton.
The skeleton, dubbed Little Foot, was discovered in the Sterkfontein caves, about 40 kilometres northwest of Johannesburg when small foot bones were found in rock blasted by miners.
Professor Ron Clarke and his assistants found the fossils and spent years to excavate, clean, analyse and reconstruct the skeleton.
The discovery is a source of pride for Africans, said Robert Blumenschine, chief scientist with the organisation that funded the excavation, the Paleontological Scientific Trust (PAST).
“Not only is Africa the storehouse of the ancient fossil heritage for people the world over, it was also the wellspring of everything that makes us human, including our technological prowess, our artistic ability and our supreme intellect,” said Blumenschine.
Adam Habib, Vice-Chancellor of the University of Witswatersrand, hailed the assembly of the full skeleton.
“This is a landmark achievement for the global scientific community and South Africa’s heritage,” said Habib. “It is through important discoveries like Little Foot that we obtain a glimpse into our past which helps us to better understand our common humanity.”
2 million-year-old ancient human skull fossils rewrite the “story of us”
Deep beneath the dust of the Cradle of Humankind, in the rolling hills northwest of Johannesburg, South Africa, archaeologists discovered a treasure trove of insights into the lives of our human ancestors.
For over a century, scientists have carefully excavated fossils which reveal how our ancient cousins lived, fought, loved, and even walked.
Now, unusual skull fragments and a constellation of fossil clues challenge the origin story of our human ancestors.
These new discoveries reveal one trait divided which species survived, and which died out: adaptability.
In this fossil trove, scientists discovered a skullcap belonging to a toddler Homo erectus.
The specimen, which researchers have named DNH 134, is the first Homo erectus fossil found in South Africa ever. It is also the earliest example of Homo erectus discovered to date. It offers solid proof that our direct human ancestor is some 150,000 to 200,000 years older than scientists thought.
Previously, the oldest Homo erectus in the world was found in Dmanisi, in Georgia, dating to 1.8 million years ago, the researchers explain. This two-year-old's skull shows they were around as many as two million years ago.
“Homo erectus was perhaps the first species we would look at and recognize as being more human-like,” Andy Herries, coauthor on the new study and paleoanthropologist at La Trobe University in Australia, tells Inverse.
Homo erectus were perhaps the first true trailblazers of the hominin family. They were the first human species to leave the African continent, and they extended their range all the way to Asia, Herries explains.
“This is ultimately the beginning of the story of us, as the great generalists, able to live in all different environments on Earth."
Amazingly, the team also found the earliest known Paranthropus robustus skull fragment too, which they named DNH 152.
The parallel discoveries reveal that three species of hominins, Homo erectus, Parathropus, and Australopithecus africansis, lived in the South African highlands simultaneously.
Herries and his team published their findings Thursday in the journal Science.
The life and times of Homo erectus
The Homo erectus skull fragments were discovered in the Drimolen Main Quarry, a notoriously challenging place to excavate, Herries says. The fossil-containing rocks there can be "as hard as concrete,” he says.
Dating the fossils once they are recovered is also a difficult process.
By using a combination of novel technologies and by comparing the skulls to other fossil fragments of lizards, bats, and soil samples, the team reconstructed a timeline of the young Homo erectus’ life and death.
The two skull fossils, DNH 134 and DNH 152, reveal that not only did they all live together, but Homo erectus, Paranthropus, and Australopithecus all possessed distinct traits that speak to their place in the human family tree.
For example, Australopithecus was more ape-like than human-like, and experienced serious “dietary stress” compared to their other hominin cousins, Herries says.
When the two other hominin species came on the scene, they developed flexible, new ways of operating that may have given them an evolutionary edge.
"Paranthropus robustus and Homo erectus arrived on the South African landscape with completely different ways of adapting to the world around them, and new technology in the form of stone and bone tools,” Herries says.
Paranthropus robustus were shorter than Homo erectus and Australopithecus, and possessed larger teeth. That trait enabled them to eat tough, hard plants, like roots and tubers.
Homo erectus, by comaprison, were taller and more slender than their peers, and ate easier to digest foods, like fruits and berries.
Ultimately, Paranthropus robustus and Homo erectus replaced Australopithecus. Part of what enabled Paranthropus robustus in particular to survive is the fact that these hominins were "specialists," Herries says. But ultimately, that same specialism may have caused their extinction.
Adaptability is the key
Unlike the other two hominins, Homo erectus' great advantage was their sheer adaptability. They could travel long distances, a crucial ability that enabled them to adjust to a rapidly changing environment.
In fact, their wandering nature is part of why Homo erectus proved to be the most successful species of ancient humans ever known, Susan Antón, an anthropologist at New York University who wasn’t involved in the study, asserts in a related commentary published in the journal Science.
The species endured for more than a million years, before going extinct half a million years ago. Their last-known residence was in present-day Java.
Homo erectus was also able to acclimatize to a changing Earth better than its fellow hominins. aranthropus and Australopithecus evolved in warm and humid climates but then the weather began to shift from warm and humid, to cool and dry. Homo erectus thrived in the cooler climate, while the other two hominins struggled to adapt.
As the climate cooled, tree-cover in the South African highlands declined, and grasses took their place. Eventually the forests were replaced with the African savannah grasslands of today.
Homo erectus were the only species among the three to endure these changes.
Homo erectus may have lived some two million years ago, but these incredible ancient humans offer lessons for humans today.
After all, we too now find ourselves in a state of environmental and social flux.
“Our work is a reminder that once upon a time we shared this world with other human species and that we are now the last remaining one,” Herries says.
“We should not be so foolish as to think that we cannot suffer the same fate as our early humans cousins, who ultimately went extinct because they were unable to adapt and innovate to challenges in their changing world.”
Homo erectus invented novel technologies, adjusted to their changing landscape, and survived longer than other hominins — all important lessons modern-day Homo sapiens may draw from.
Ultimately, the pair of discoveries shed light on a critical period of time in the human story. These first steps are what has led to our globalized world today, Herries says.
“It is also a reminder in these unconnected times, with border closures and an increasing fear of other people and groups, that we are ultimately one family, all connected by a common origin in Africa," Herries says.
"We should be working together to fight the challenges of the future, both in terms of pandemics and climate change."
2.04 million to 1.95 million years old, DNH 152 represents the earliest definitive occurrence of Paranthropus robustus, and DNH 134 represents the earliest occurrence of a cranium with clear affinities to Homo erectus. These crania also show that Homo, Paranthropus, and Australopithecus were contemporaneous at
2 million years ago. This high taxonomic diversity is also reflected in non-hominin species and provides evidence of endemic evolution and dispersal during a period of climatic variability.
'Game changing' skull of 3.8 million year old human ancestor discovered
The discovery is said to challenge previous assumptions of a linear transition between two early human ancestor species..
Wednesday 28 August 2019 20:16, UK
Scientists have recreated the face of an early human ancestor after a "remarkably complete" skull dating back 3.8 million years was found in Ethiopia.
Researchers dug up the cranium at the Woranso-Mille palaeontology site in the northeastern Afar region of the African country after 15 years of work.
Dr Yohannes Haile-Selassie, of Cleveland Museum of Natural History and Case Western Reserve University, said the discovery was a "game changer in our understanding of human evolution" as it challenges previous assumptions of a linear transition between two early human ancestor species.
The Australopithecus anamensis species is known to have existed between 3.9 million and 4.2 million years ago - but the newly discovered fossil is 3.8 million years old.
This means Australopithecus anamensis must have co-existed for around 100,000 years with the species that came next - Australopithecus afarensis (also known as Lucy).
The international team said: "A. anamensis was already a species that we knew quite a bit about, but this is the first cranium of the species ever discovered. It is good to finally be able to put a face to the name."
Australopithecus anamensis is the oldest known species that is unambiguously part of the human evolutionary tree.
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Dr Haile-Selassie said uncovering the fossil was a "eureka moment" for his team, with most of the cranium having been found after the separate discovery of its upper jaw in February 2016.
The skull - detailed in the journal Nature - is one of more than 12,600 fossil specimens collected by the Woranso-Mille project since 2004, representing approximately 85 mammalian species.
In a companion paper published in the same journal, Professor Beverly Saylor of Case Western Reserve University and her colleagues explained how the age of the skill was determined.
Researchers dated minerals in layers of volcanic rocks nearby to come to their conclusion, mapping out the area using field observations and the chemistry and magnetic properties of the rock layers.
From there, they were able to reconstruct the landscape, vegetation and hydrology where the specimen - which has been labelled as MRD - died.
It was found in the sandy deposits of a delta where a river entered a lake, having likely flowed from the highlands.
The lake formed in an area of steep hillsides and volcanic eruptions that blanketed the land with ash and lava.
Other clues as to the environment in which the specimen lived were provided by fossil pollen grains and the chemical remains of plants and algae, which are preserved in the lake and delta sediments.
Study co-author Naomi Levin, from the University of Michigan, said: "MRD lived near a large lake in a region that was dry. We're eager to conduct more work in these deposits to understand the environment of the MRD specimen, the relationship to climate change and how it affected human evolution, if at all."
National Museum of Natural HistorySome of the most exciting discoveries in human evolution happened in the last decade. (Human Origins Program, Smithsonian Institution)
Human evolution is one of the most vibrant areas of scientific investigation. In the past decade we’ve seen many discoveries that add to our understanding of our origins. To mark the 10th anniversary of the Smithsonian’s “David H. Koch Hall of Human Origins,” here are some of the biggest discoveries in human evolution from the last 10 years.
We have ancient DNA
Scientists extracted ancient DNA from this 76,000-52,000-year-old fossil pinky bone in 2010, leading to the identification of the Denisovan population. (Max Planck Institute for Evolutionary Anthropology)
DNA tells us a lot about who we are now. But we also look to ancient DNA to learn about our origins.
When the decade first started, scientists recovered ancient genetic material from a fossilized finger bone found in the Denisova Cave in Siberia. They tested that material and discovered that the DNA didn’t match that of modern humans or Neanderthals. Instead, it belonged to a previously undiscovered species of early humans now called Denisovans. It was the first time a new species has been identified using ancient DNA.
What does this tell us? The human genome is a wondrous archive of our relationships with ancient species no longer around.
Meet our new ancestors
737 fossils of Homo naledi, a new early human species announced in 2015. (Image by John Hawks/Courtesy of University of the Witwatersrand)
Over the past decade, we welcomed four new species to our family tree, including the mysterious Homo naledi.
In 2015, scientists announced the discovery of fossils of at least 15 individuals of this species in a deep, dark chamber of the Rising Star Cave system in South Africa. It's five years later and we still aren’t sure how they got there. There’s no evidence they were dragged there by predators or washed in by water. And no other animal bones were found in the cave except for the bones of a single owl. Were the bodies placed there deliberately? If so, by whom? It’s a mystery still to be solved.
What we do know is that the remains are from 335,000-236,000 years ago and show a unique mix of ancient and human traits, making Homo naledi one of several species that overlapped in time with our own.
Fossil discoveries tell more of our story
This 3.8-million-year-old cranium of Australopithecus anamensis helped scientists see how the face of an early human species looked. (Photograph by Dale Omori, courtesy of the Cleveland Museum of Natural History)
Not all fossil discoveries lead to a new species. But new fossils always reveal more of our story.
In the past ten years, we’ve found fossils that widen both the geographic and time range of several early human species. But one of the most exciting discoveries is of a nearly complete 3.8-million-year-old cranium of Australopithecus anamensis from Woronso-Mille, Ethiopia. Until this find was announced in 2019, researchers had only found bits and pieces of this species from various sites across Ethiopia and Kenya.
Fossils older than 3.5 million years are extremely rare. But what makes this discovery particularly amazing is that it challenges the previous assumption that A. anamensis was the direct ancestor of the species Australopithecus afarensis—to which the famous fossil “Lucy” belongs. Thanks to this skull, we now know that the two species overlapped in time.
We made tools earlier than we thought
A 3.3-million-year-old stone tool in situ at the Lomekwi 3 excavation site in Kenya. (Mission Préhistorique au Kenya/West Turkana Archaeological Project)
When you think of technology today, you might picture computers, smartphones, and gaming consoles. But for our ancestors millions of years ago, it would have been stone tools.
We long thought our ancestors began making these tools about 2.6 million years ago. But a discovery announced in 2015 pushed that date back. The research team found pieces of altered stone in Lomekwi, Kenya, that date to 3.3 million years ago. These stones are larger and simpler than those that were previously thought to be the oldest stone tools.
The new discovery suggests that the ability to flake stone tools arose at least 700,000 years before it became a regular habit in the lives of our ancestors.
We’re older than we thought
Reconstructions of the earliest known Homo sapiens fossils based on CT scans of multiple original fossils. (Philipp Gunz, MPI EVA Leipzig, License: CC-BY-SA 2.0)
Stone tools aren’t the only things that are older than we thought. Humans are too.
Just three years ago, a team of scientists made a discovery that pushed back the origin of our species, Homo sapiens. The team re-excavated a cave in Morocco where a group of miners found skulls in 1961. They collected sediments and more fossils to help them identify and date the remains. Using CT scans, the scientists confirmed that the remains belonged to our species. They also used modern dating techniques on the remains. To their surprise, the remains dated to about 300,000 years ago, which means that our species originated 100,000 years earlier than we thought.
Social Networking Isn’t New
Obsidian from Olorgesailie, Kenya revealed that social networks existed long before we thought. (Human Origins Program, Smithsonian Institution)
With platforms like Facebook, Twitter and Instagram, it hard to imagine social networking being old. But it is. And, now, it’s even older than we thought.
In 2018, scientists discovered that social networks were used to trade obsidian, valuable for its sharp edges, by around 300,000 years ago. After excavating and analyzing stone tools from southern Kenya, the team found that the stones chemically matched to obsidian sources in multiple directions of up to 55 miles away. The findings show how early humans related to and kept track of a larger social world.
We left Africa earlier than we thought
2.1-million-year-old stone tools from the site of Shangchen on the Loess Plateau of central China. (Zhu Zhaoyu, Chinese Academy of Sciences)
We’ve long known that early humans migrated from Africa not once but at least twice. But we didn’t know just how early those migrations happened.
We thought Homo erectus spread beyond Africa as far as eastern Asia by about 1.7 million years ago. But, in 2018, scientists dated new stone tools and fossils from China to about 2.1 million years ago, pushing the Homo erectus migration to Asia back by 400,000 years.
Also in 2018, researchers announced the discovery of an upper jaw in Israel that looked like that of our own species, Homo sapiens. The jaw ended up being 174,000-185,000 years old. This discovery—along with others from China and Greece—suggest that Homo sapiens wandered short-term into Eurasia well before the worldwide migration that began 70,000 years ago.
Briana Pobiner leads the National Museum of Natural History’s Human Origins Program’s education and outreach efforts and manages the Human Origins Program's public programs. Her research centers on the evolution of human diet (with a focus on meat-eating), but has included topics as diverse as human cannibalism and chimpanzee carnivory. Her favorite field moments include falling asleep in a tent in the Serengeti in Tanzania while listening to the distant whoops of hyenas, watching a pride of lions eat a zebra carcass on the Kenyan equator, and discovering fossil bones that were last touched, butchered and eaten by one of her 1.5-million-year-old ancestors.
Paleoanthropologist Dr. Rick Potts heads the Human Origins Program at the Smithsonian’s National Museum of Natural History. In partnership with the Kenya Museums, Potts leads ongoing excavations in southern and western Kenya. His research focuses on how environmental instability has affected human evolution and our evolutionary adaptations. He is the curator of the Smithsonian’s "Hall of Human Origins" and the traveling exhibit “Exploring Human Origins.” He also authored the exhibit companion book What Does It Mean To Be Human?
In October, a team led by Nina Jablonski and Xueping Ji from Penn State University and Yunnan Institute of Cultural Relics and Archaeology respectively, found three new Mesopithecus pentelicus fossils, about 6.4 million years old, in Yunan Province, China. These late Miocene fossils indicate that this ecologically versatile and adaptable ancient monkey lived in Asia at the same time as apes. Modern colobines of Asia, the likely descendants of this species, have continued this trend by inhabiting some of the most highly seasonal and extreme habitats occupied by nonhuman primates.
Rare 10 million-year-old fossil unearths new view of human evolution
Rudapithecus was pretty ape-like and probably moved among branches like apes do now -- holding its body upright and climbing with its arms. However, it would have differed from modern great apes by having a more flexible lower back, which would mean when Rudapithecus came down to the ground, it might have had the ability to stand upright more like humans do. Credit: John Siddick
Near an old mining town in Central Europe, known for its picturesque turquoise-blue quarry water, lay Rudapithecus. For 10 million years, the fossilized ape waited in Rudabánya, Hungary, to add its story to the origins of how humans evolved.
What Rudabánya yielded was a pelvis—among the most informative bones of a skeleton, but one that is rarely preserved. An international research team led by Carol Ward at the University of Missouri analyzed this new pelvis and discovered that human bipedalism—or the ability for people to move on two legs—might possibly have deeper ancestral origins than previously thought.
The Rudapithecus pelvis was discovered by David Begun, a professor of anthropology at the University of Toronto who invited Ward to collaborate with him to study this fossil. Begun's work on limb bones, jaws and teeth has shown that Rudapithecus was a relative of modern African apes and humans, a surprise given its location in Europe. But information on its posture and locomotion has been limited, so the discovery of a pelvis is important.
"Rudapithecus was pretty ape-like and probably moved among branches like apes do now—holding its body upright and climbing with its arms," said Ward, a Curators Distinguished Professor of Pathology and Anatomical Sciences in the MU School of Medicine and lead author on the study. "However, it would have differed from modern great apes by having a more flexible lower back, which would mean when Rudapithecus came down to the ground, it might have had the ability to stand upright more like humans do. This evidence supports the idea that rather than asking why human ancestors stood up from all fours, perhaps we should be asking why our ancestors never dropped down on all fours in the first place."
Modern African apes have a long pelvis and short lower back because they are such large animals, which is one reason why they typically walk on all fours when on the ground. Humans have longer, more flexible lower backs, which allow them to stand upright and walk efficiently on two legs, a hallmark characteristic of human evolution. Ward said if humans evolved from an African ape-like body build, substantial changes to lengthen the lower back and shorten the pelvis would have been required. If humans evolved from an ancestor more like Rudapithecus, this transition would have been much more straightforward.
"We were able to determine that Rudapithecus would have had a more flexible torso than today's African apes because it was much smaller—only about the size of a medium dog," Ward said. "This is significant because our finding supports the idea suggested by other evidence that human ancestors might not have been built quite like modern African apes."
- A fossil pelvis from Rudapithecus. The pelvis is among the most informative bones of a skeleton, but one that is rarely preserved. Credit: Carol Ward
- Carol Ward, a Curators Distinguished Professor of Pathology and Anatomical Sciences in the MU School of Medicine, and her team used new 3D modeling techniques to digitally complete the fossil's shape, then compared their models with modern animals. Credit: University of Missouri
- A Rudapithecus pelvis fossil, center, overlain on a skeleton of a siamang, compared with a macaque on the left and orangutan on the right. Credit: University of Missouri
Ward teamed up with Begun to study the pelvis along with MU alumna Ashley Hammond, Assistant Curator of Biological Anthropology at the American Museum of Natural History, and J. Michael Plavcan, a professor of anthropology at University of Arkansas. Since the fossil was not 100% complete, the team used new 3-D modeling techniques to digitally complete its shape, then compared their models with modern animals. Ward said their next step will be to conduct a 3-D analysis of other fossilized body parts of Rudapithecus to gather a more complete picture of how it moved, giving more insight into the ancestors of African apes and humans.
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Prof Haile-Selassie says the specimen is the best example yet of the ape-like human ancestor called Australopithecus anamensis - the oldest known australopithecine whose kind may have existed as far back as 4.2 million years ago.
It had been thought that A. anamensis was the direct ancestor of a later, more advanced species called Australopithecus afarensis, which in turn has been considered a direct ancestor of the first early humans in the grouping, or genus, known as Homo, and which includes all humans alive today.
The discovery of the first afarensis skeleton in 1974 caused a sensation. She was nicknamed Lucy by researchers after the Beatles song, Lucy in the Sky With Diamonds, which was playing at the excavation site.
Hailed as "the first ape to have walked", Lucy captured the public's attention. But writing a commentary in Nature, Prof Fred Spoor, of London's Natural History Museum, said that anamensis "looks set to become another celebrated icon of human evolution".
The reason for this likely elevated status is because we can now say that anamensis and afarensis actually overlapped in time. The former did not evolve directly into the latter in a neat linear manner, as previously supposed.
The realisation comes about through the reinterpretation that the new fossil brings to bear on a previously discovered 3.9-million-year-old skull fragment. That fragment had been assigned to anamensis. Scientists can now see it is actually the remains of an afarensis, pushing this species' origin deeper into the past.
It's apparent now the two species must have co-existed for at least 100,000 years.
What most likely happened was that a small group of anamensis isolated itself from the main population and over time evolved into afarensis because of adaptations to local conditions. The two types rubbed along for a while before the remnant anamensis died out.
The finding is important because it suggests that additional overlaps with other advanced ape-like species may also have occurred, increasing the number of potential evolutionary routes to the first humans.
In short, although this latest discovery does not disprove that Lucy's kind gave rise to the Homo group, it does bring other recently named species into contention. Prof Haile-Selassie agreed that "all bets are now off" as to which species is humanity's direct ancestor.
He explained: "For a long time, afarensis was considered the best candidate as an ancestor to our kind, but we are not in that position any more. Now we can look back at all the species that might have existed at the time and examine which one may have been most like the first human."
The term "missing link" drives anthropologists crazy when they hear anyone, especially journalists, use it to describe a fossil that is part-ape and part-human.
Indeed Dr Henry Gee, a senior editor at Nature, once threatened to "rip my liver out and eat it with onions, borlotti beans and a glass of claret" if I did so when reporting a previous discovery.
There are many reasons for Henry's irritation, but chief among them is the recognition that there are many links in the chain of human evolution and most if not nearly all of them are still missing.
Anamensis is the latest in a string of recent discoveries that shows that there was no smooth line of ascent to modern humans.
The truth is far more complex and far more interesting. It tells a story of evolution "trying out" different "prototype" human ancestors in different places until some of them were resilient and clever enough to withstand the pressures wrought by changes in climate, habitat and food scarcity - and evolve into us.
Prof Haile-Selassie is one of the few African scientists working in human evolution. He is now a recognised name but he says it's hard for well qualified African researchers to get the necessary financial backing from Western-based research funding organisations.
"Most of the fossil evidence related to our origin comes from Africa and I think Africans should be able to use the resources available in their own continent and advance their career in palaeoanthropology. Their limitations getting to this field of study is usually funding," he told me.
Seeking Ancestral Commonalities with Modern Human Body Type, Researchers Find Stockier Answer
An ancestor to modern humans had a stockier build than previously thought—one that is quite different from today’s human body—a team of paleoanthropologists has discovered.
An ancestor to modern humans had a stockier build than previously thought—one that is quite different from today’s human body—a team of paleoanthropologists has discovered. This newly established distinction suggests that the modern human body evolved more recently than once believed.
The findings, centering on Homo erectus, which appeared approximately two million years ago, are in the latest issue of the journal Nature Ecology and Evolution.
“Our own body shape with its flat, tall chest, and narrow pelvis and rib cage likely appeared only recently in human evolution with our species, Homo sapiens,” says Scott Williams, an associate professor in New York University’s Department of Anthropology and one of the paper’s co-authors.
Reconstructed upper body skeleton of the 1.5 million years old Homo erectus youth from West Turkana, Kenya. The ribcage was deeper, wider and shorter than in modern humans, suggesting a stockier body shape and a larger lung volume. Licence CC-BY-NC-ND 4.0 Image by Markus Bastir.
The authors of the study, led by Markus Bastir of Madrid’s Museo Nacional de Ciencias Naturales and Daniel García-Martínez of Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Burgos, Spain, speculate that these changes to our body shape may have optimized breathing capabilities for long-distance running and other endurance activities.
“That Homo erectus was perhaps not the lean, athletic long-distance runner we imagined is consistent with more recent fossil finds and larger body weight estimates than previously obtained,” notes Fred Spoor of London’s Natural History Museum and the paper’s senior author. “This iconic ancestor was probably a little less like us than we portrayed it over the years.”
The work reveals for the first time what the three-dimensional shape of the ribcage of the Homo erectus skeleton, known as the Turkana Boy, looked like. Discovered west of Lake Turkana, Kenya in the mid-1980s, the 1.5-million-year-old fossil is the most complete skeleton of a fossil human ancestor ever found.
Specifically, it had a deeper, wider and shorter chest than seen in modern humans, suggesting that Homo erectus had a stockier build than commonly assumed. It thus appears that the fully modern human body shape evolved more recently than scientists previously concluded, rather than as early as two million years ago—when Homo erectus first emerged.
“The results are now changing our understanding of Homo erectus,” says lead author Bastir. “Its thorax was much wider and more voluminous than that of most people living today.”
“Actually, the ribcage of Homo erectus seems more similar to that of more stocky human relatives such as Neandertals, who would have inherited that shape from Homo erectus,” adds García Martínez.
The evolution of the modern human body shape is a fascinating transformation in light of the way we and our ancestors are adapted to our natural environment, the scientists observe. As modern humans, we have a relatively tall, slender body shape that contrasts with the shorter, stocky, heavy bodied Neandertals.
Studies of how Turkana Boy walked and ran had largely been restricted to the skeleton’s legs and pelvis. However, for endurance running its breathing capabilities would have been relevant as well. But this aspect has not before been investigated in any detail because assessing the chest and breathing motion based on a jumble of rib and vertebra fossils is difficult with conventional methods. However, with the introduction of increasingly sophisticated imaging and reconstruction techniques in recent years this type of examination is now possible.
In the new research, a three-dimensional virtual ribcage of the Turkana Boy could be reconstructed, and its adult shape could be predicted had this adolescent fully grown up. The ribcage shape was compared with that of modern humans and a Neandertal, with virtual animation allowing breathing motion to be investigated.