Tag Archives: Homo Erectus

An unknown ancestor mated with ancient humans. Its DNA is found in living people to this day

The unidentified ancient human relative may have been Homo erectus. Credit: flowcomm, Flickr.

To say the sex lives of our ancestors was complicated would be an understatement. After they migrated out of Africa into Eurasia, humans interbred with Neanderthals, Denisovans, and at least one other group of archaic people belonging to our genus. Evidence of this latter interbreeding lives on in our genes, according to a new study by researchers in the United States. The identity of this group is still shrouded in mystery.

When Homo sapiens migrated in large numbers out of Africa through the Middle East into Europe and Asia, they came in contact with the Neanderthals, who had been masters of their domains for thousands of years prior to the arrival of anatomically modern humans. The two species interbred, the effects of which are still seen in the genomes of people alive today who are not of Sub-Saharan heritage. About 2% of the DNA in the genomes of modern-day people with Eurasian ancestry is Neanderthal in origin.

But the gene flow goes both ways, of course. In a new study, Melissa Hubisz and Amy Williams of Cornell University and Adam Siepel of Cold Spring Harbor Laboratory performed a complex genomic analysis of the DNA of two Neanderthals, a Denisovan and two living African humans. The latter have no Neanderthal DNA in their genomes, as opposed to Caucasians, which helped the researchers differentiate patterns of ancient interbreeding.

The team of researchers employed a computational method that enabled them to identify recombination events, in which segments of the chromosomes from one individual become incorporated into the chromosomes of another. This clever method can map out the tree of relationships among individuals at every position along the genome.

In more practical terms, this approach enabled the researchers to uncover previous instances of mating nested in the genomes of living or extant species. For instance, if Neanderthals mated with some other human species, and later these descendants mated with modern humans, this method can uncover that initial instance of ancient interbreeding.

As it turned out, the study revealed some amazing instances of such nested insections of DNA. For instance, 3% of the Neanderthal genomes came from ancient humans, estimated to have occurred 200,000 to 300,000 years ago. This is additional evidence supporting the fact that humans left Africa in multiple waves before making a huge leap out of the continent primarily 50-60,000 years ago. These early migratory waves of humans were likely assimilated by Neanderthals or were wiped out one way or the other.

But the most striking finding was that 1% of the Denisovan DNA came from a yet unidentified species of ancient humans. The interbreeding occurred roughly one million years ago, a timeline that suggests the lover may have been Homo erectus. Sadly, no Homo erectus DNA has ever been found, so this hypothesis remains speculation at this point. It may very well have been some different, yet to be identified species altogether.

In any event, both interbreeding events have been passed down to living modern humans. About 15% of the interbreeding sequences found in the Denisovans are present in living people today, the researchers reported in the journal PLoS Genetics.

Given the sheer number of gene exchanges between ancient humans and their extinct relatives, it’s very likely that genetic exchange took place whenever two distinct groups of humans overlapped in time and space. The same algorithm employed by the study could be used to study gene flow in other species where interbreeding occurred in the distant past, such as between wolves and dogs.

“What I think is exciting about this work is that it demonstrates what you can learn about deep human history by jointly reconstructing the full evolutionary history of a collection of sequences from both modern humans and archaic hominins,” Siepel said in a statement. “This new algorithm that Melissa has developed, ARGweaver-D, is able to reach back further in time than any other computational method I’ve seen. It seems to be especially powerful for detecting ancient introgression.”

Scientists find 1.4 million-year-old hand axe made out of hippo femur

This 1.4-million-year-old hand axe is made out of a hippo’s thigh bone. Credit: Berhane Asfaw, University of Tokyo.

Hand axes are some of the most versatile tools humans have ever invented. You can use it to chop wood for a fireplace, butcher freshly caught game, defend against predators and other humans, or build other tools with it.

It’s no wonder then that hand axes are also the most common artifacts archaeologists and anthropologists have found, the earliest dating between one and two million years ago.

Prehistoric hand axes are typically made from stone, but researchers doing fieldwork at the Konso Formation in southern Ethiopia found one that was made out of a large chunk of bone. Turns out that the bone is actually the femur of an ancient hippotamus.

The Konso hand axe is only the second such tool completely made out of bone. Judging from the sediments from which the artifact was unearthed, the femur hand axe is around 1.4 million years old.

In all likelihood, this timeline suggests that the tool was manufactured by Homo erectusthe first hominin to have fully walked upright. They also shared many other features with modern humans, which enabled them to be quite successful, spreading from Africa across Europe and Asia.

An intelligent and skilled toolmaker

Forensic reconstruction of an adult female Homo erectus. Credit: Wikimedia Commons.

Homo erectus had little body hair, so it was able to shed heat and be active throughout the day. The appearance of the vestibulocochlear apparatus — a part of the inner ear involved in balance and movement present in modern humans — allowed H. erectus to see distant targets well.

These adaptations may have heralded a change from scavenging to hunting in our species’ lineage. This is further evidenced by the hominin’s smaller gut and teeth relative to its predecessors, which suggest it had a better diet. Bone protein released during cooking suggests that H. erectus also knew how to make a fire or at least use naturally-occurring fires.

This hominin grew tall and had long legs, making it a completely terrestrial creature. It may have used a proto-language, as indicated by the vertebrae fossils of Homo erectus georgicus, a sub-species of Homo erectus.

Like the familiar stone hand axes, the Konso was likely fashioned in the same way, by chipping bits off of the femur bone until the edge became sharp. The axe is about 13 centimeters long and has an oval shape, according to the University of Tokyo paleoanthropologist Gen Suwa, who led the new study along with his colleagues from Japan, Ethiopia, and Hong Kong.

“This bone handaxe shows that at Konso, not only in lithic technology, but also in bone modification, Homo erectus individuals were sufficiently skilled to make and use a durable cutting edge,” the scientists said.

Research conducted previously found that ancient hominins like H. erectus manufactured such hand axes using a single sharp blow to create a new tool edge. This edge would then be honed through repeated chipping with a bone or stone hammer. As many as 44 secondary flake scars were identified by the researchers, which ranged in size from 3 cm to less than 1 cm.

“Both the distribution pattern of flake scars and the high frequency of cone fractures are strong indicators of deliberate flaking,” the researchers wrote in their study published in PNAS.

The axe was likely used for butchering animals

The Konso hand axe seen from various angles. Credit: Sano et al, PNAS.

Whoever was the toolmaker, he must have been quite skilled. There’s a reason why so few bone tools have been recovered by archeologists. Besides being less able to withstand the degradation of time, bone requires more craftsmanship to shape into a tool than stone does. The toolmaker has to find just the right bone for the job and then carefully apply proper blows and chipping so the bone doesn’t break entirely.

“The handaxe is made with substantial sophistication as evidenced by, for example, the large number of small, well-controlled cortical side removals in forming the handaxe-like shape,” the researchers said.

“The finer bifacial flaking made a relatively straight edge in a side view, which enables efficient cutting.”

The bone hand axe bears evidence of wear, suggesting it had been used. The edge is rounded in places near the tip, similar to stone tools used for butchering animals.

It’s not clear why the toolmaker would choose bone over stone, despite the latter being available in ample amounts in the area. Nevertheless, we’re grateful now that such an artifact has withstood the test of time, highlighting the intelligence of H. erectus, who may very well be a direct ancestor of our species.

“The discovery of the finely made Konso bone handaxe from 1.4 million years ago shows that refinement of flaking technology in the early Acheulean involved both stone and bone and provides additional evidence of the technological and behavioral sophistication of African Homo erectus through Acheulean times,” the authors said.

Scientists find the earliest evidence of ancient human interbreeding

Lateral view of the Dali cranium. Most of the cranial dimensions and morphological features of Dali were intermediate between Homo erectus and H. sapiens. Credit: Peter Brown paleontology.

A novel method for analyzing ancient DNA has allowed scientists to peer into the distant past of the human lineage — farther than ever before. In doing so, the earliest interbreeding event between archaic human populations has been discovered, dating to 700,000 years ago.

“We’ve never known about this episode of interbreeding and we’ve never been able to estimate the size of the super-archaic population,” said Alan Rogers, lead author of the study and a professor of anthropology at the University of Utah. “We’re just shedding light on an interval on human evolutionary history that was previously completely dark.”

In 2017, Rogers published a study that found Neanderthals and Denisovans split earlier than previously thought. This caused quite the debate among scholars who came up with different results.

Something was missing — and this new study’s findings might solve the puzzle. It suggests that a previously unidentified population of ancient human populations — known as “super-archaics” — interbred with a Neanderthal-Denisovan ancestor in Eurasia about 700,000 years ago.

Rogers and colleagues analyzed the genomes of modern Africans and Europeans, specifically looking for any shared mutations between the two populations. The pattern of mutation suggests that our species has inherited genes from at least five distinct episodes of interbreeding — one of them was previously unknown.

Modern humans and Neanderthals were separated for about 750,000 years before they interbred. The new study suggests that super-archaics and the Neanderthal-Denisovan lineage were separated for well over a million years, making them the most distant pair of ancient human populations that interbred.

Using other clues etched in the modern day genomes, the researchers estimated that the super-archaic group separated into its own species about two million years, which is in agreement with fossil evidence in Eurasia dated to 1.85 million years ago.

“These findings about the timing at which interbreeding happened in the human lineage is telling something about how long it takes for reproductive isolation to evolve,” said Rogers.

These results indicate that there were at least three waves of human migration into Eurasia, the first starting two million years ago when these super-archaics started expanding out of Africa. Then, about 700,000 years ago, the Neanderthal-Denisovan ancestors migrated into Eurasia where they encountered the super-archaics, interbreeding with them. Finally, modern humans crossed into Eurasia about 50,000 years ago where they interbred with Neanderthals, Denisovans, and quite possibly other ancient human species.

“I’ve been working for the last couple of years on this different way of analyzing genetic data to find out about history,” said Rogers. “It’s just gratifying that you come up with a different way of looking at the data and you end up discovering things that people haven’t been able to see with other methods.”

Around 1.6 million years ago, the first large-brained hominin appeared on the evolutionary landscape. Known as Homo ergaster, this hominin had a more modern skeleton and employed advanced food-gathering methods. According to the fossil evidence, it was the first hominin to make it out of Africa, its remains having been found as far as Dmanisi, in the Republic of Georgia, as well as in several places in southern Europe.

Homo ergaster gave rise to Homo erectus, which quickly dominated the landscape. By 700,000 years ago, Homo erectus could be found from the river valleys in Indonesia to the open savannas in Africa. The resourceful Homo erectus had mastered fire, stone tool technology, and incorporated hunting into its daily life.

If Homo erectus wasn’t the now-extinct traveler that interbred with Neanderthal-Denisovan ancestors, then perhaps that distinction might belong to  Homo antecessor, a controversial species designation based on 1.2-million- to 1.1-million-year-old fossils found in Spain. Alternatively, this may be an as of yet unidentified Homo population.

It’s remarkable when you realize that all of this insight is based on information stored in our genomes. The findings show that our lineage is far from pure. Instead, we’re the product of countless encounters with other species, as well as that of the environment. And as scientists’ abilities to interpret the genome improve, we’re bound to learn much more about what forces shaped humanity.

The findings were reported in the journal Science Advances.

First human ancestor to walk on two legs made its final stand in Java

A million years before humans made their first baby steps out of Africa, one of our ancestors was already busy fashioning tools and exploring the world walking on two legs. Homo erectus is famous for being the first hominin to walk upright. Now, a new study suggests that our ancestor was the most successful member of the genus Homo, having survived from 1.8 million years ago until as recently as 108,000 years ago.

The Ngandong site. Credit: Russel Ciochon.

The Ngandong terrace, a floodplain on the Indonesian island of Java, is the site of the largest collection of Homo erectus fossils in the world, showing that the human ancestor was able to travel a huge distance from its birthplace in Africa. Nearly a century ago, anthropologists have unearthed at least a dozen partial skulls and two shin bones at the site.

For a long time, scientists have tried to date the site, but until recently all these efforts return wildly different estimates from as early as 27,000 to half a million years old. The fact that the original bonebed first excavated by Dutch geologists in the 1930s had been lost made the investigation all the more challenging.

In their new study, researchers at the University of Iowa and the Institute of Technology in Bandung, Indonesia, used modern techniques (uranium-series dating, luminescence, and electron-spin resonance) to date the landscape and some animal fossils excavated from the Ngandong terrace. To find the original bonebed, the researchers employed maps and journals inherited by the grandchildren of one of the Dutch geologists.

Ngandong bonebed. Credit: University of Iowa.

They also dated the stalagmites in the caves of nearby mountains, showing that the mountains themselves rose at least half a million years ago, diverting the Solo river into the Kendeng hills and forming the Ngandong terrace. Entangling the thread even further, the researchers found that the terrace is between 140,000 and 92,000 years old.

Although they couldn’t find new Homo erectus fossils, the researchers gathered hundreds of animal remains — ranging from water buffalo to elephants — which were found in the same layer as the Homo erectus skulls. Using a sophisticated computer model, the researchers weighed the different dates for each fossil, coming up with an age range of the site.

They conclude that although Homo erectus went extinct in many other parts of the world by this date, the species survived on Java until 108,000 to 117,000 years ago. Modern humans arrived on the island about 35,000 years after the last known appearance of Homo erectus.

“This site is the last known appearance of Homo erectus found anywhere in the world,” says Russell Ciochon, co-corresponding author on the study. “We can’t say we dated the extinction, but we dated the last occurrence of it. We have no evidence Homo erectus lived later than that anywhere else.”

A Homo erectus skull cap found at the Ngandong site. Credit: Griffith University.

This means that around the same time, our species, Homo sapiens, shared the planet with at least seven other different hominin species, including Denisovans and Neanderthals.

Around 130,000 years ago, the environment at Ngandong changed, and perhaps this may have sealed Homo erectus’ fate.

“There was a change in climate,” Ciochon explains. “We know the fauna changed from open country, grassland, to a tropical rainforest (extending southward from today’s Malaysia). Those were not the plants and animals that Homo erectus was used to, and the species just could not adapt.”

However, considering that the researchers couldn’t find direct evidence of Homo erectus fossils, the debate isn’t settled yet. For instance, the animals at the site could have been butchered by Denisovans whose presence in the area is established. More research may provide more insight in order to clear some of the mist surrounding the Ngandong site.

The findings appeared in the journal Nature.

The excavations in the Philippines revealed the earliest evidence of homininds on the islands. Researchers found rhino bones (shown) and stone tools. Credit: T. INGICCO.

Butchered rhino bones and stone artifacts suggest hominids were in Philippines 709,000 years ago

A trove of stone tools and animal bones indicate that hominids had reached the Philippines as early as 709,000 years ago. Previously, the earliest evidence of a hominid presence in the Southeast Asian archipelago came from a human toe bone roughly 68,000 years old, which was found in a river floodplain on the northern island of Luzon.

The excavations in the Philippines revealed the earliest evidence of homininds on the islands. Researchers found rhino bones (shown) and stone tools. Credit: T. INGICCO.

The excavations in the Philippines revealed the earliest evidence of homininds on the islands. Researchers found rhino bones (shown) and stone tools. Credit: T. Ingicco.

The new evidence reported in the journal Nature involves 57 stone artifacts and more than 400 animal bones, including the disarticulated skeleton of a butchered rhinoceros. The other animal fossils came from brown deer, monitor lizards, freshwater turtles and extinct, elephant-like extinct creatures called stegodons.

These precious tools and fossils excavated in the landlocked northern region of Kalinga in the Philippines pose two very important questions. Firstly, who made these tools and butchered the animals? The second question deals with dispersion: how did the tool-makers (and a rhino, for that matter) end up on islands that are too far away from land to swim?

According to lead author Thomas Ingicco of the National Museum of Natural History in Paris, the radioactive decay in elements present in Kalinga sediment and the excavated rhino tooth suggest that the fossils are roughly 709,000 years old (give or take 68,000 years). Around that time, one of our ancestors, a hominid called Homo erectus, was already present throughout much of the Asian continent. In places like China or Indonesia, there is evidence that Homo erectus was around as early as 1.8 million years ago.

So, despite lacking direct evidence, circumstances point to Homo erectus as the butcher of the rhino and toolmaker of the stone artifacts. Another possibility is that the Kalinga toolmakers were actually Homo floresiensis, also known as the Hobbit Humans, named so because of their diminutive size. According to the most comprehensive study of its bones, the species of tiny human discovered on the Indonesian island of Flores in 2003 most likely evolved from an ancestor in Africa and not from Homo erectus as has been widely believed. Homo floresiensis probably went extinct by at least 13,000 years ago — that’s very recently relative to evolutionary timelines. Unfortunately, we can’t know who the toolmaker was — whether H. erectus, H. floresiensis, or some other unknown Homo species — judging from the stone artifacts alone.

Stone artificats retrieved from the Kalinga site. Credit: Ingicco et al./Nature.

Stone artificats retrieved from the Kalinga site. Credit: Ingicco et al./Nature.

Whoever it was, the hominids likely arrived in the Philippines via one of four possible routes, according to the authors. These would be: China via Taiwan, Sulawesi via the Sangihe Islands, Borneo via the Sulu Archipelago, and Borneo via Palawan Island. Colonization would have been made possible thanks to natural rafts, such as floating mangroves that typhoons occasionally break off the coast. The researchers also don’t rule out the possibility that the hominids fashioned their own watercraft.

As for the striking rhino fossils, these belong to the now-extinct Rhinoceros philippinensis. The hominids seem to have savored their prey, as cut marks show that the animal was stripped of its meat and its bones were smashed to gain access to the marrow. About 75% of the rhino’s skeleton was found during the excavation.

Only two others sites —  Choukoutien in China and Ngebung in the Sangiran Dome of Java — have provided evidence of butchered animals in Southeast Asia as old as Kalinga.

These are all very exciting findings, which will keep anthropologists eager to dig for more.

“There’s a lot of focus again in the islands of South East Asia because they are places where you find natural experiments in hominin evolution. That’s what makes Flores unique, and now Luzon is another place we can start looking for fossil evidence,” said Gerrit van den Bergh, an archaeologist at the University of Wollongong in Australia and co-author of the new paper.

 

Virtual endocast of H. floresiensis (left) vs H. sapiens (right). Credit: rofessor Peter Brown, University of New England.

‘Hobbits’ didn’t evolve from a direct modern human ancestor. They likely originate from Africa instead

Until some 17,000 years ago, we humans shared the Earth with another close relative: Homo floresiensis. Often called the ‘hobbit’ because of its dwarfish stature, scientists have long debated the origin of this species first discovered as recently as 2003 in the Liang Bua cave on the remote Indonesian island of Flores. Now, scientists who embarked on the most comprehensive analysis of H. floresiensis yet claim the debate is over. The hominid is a distant relative to modern humans and, instead, likely evolved from another branch of hominid from Africa.

Homo Floresiensis skull. Credit: Stuart Hay - ANU.

Homo Floresiensis skull. Credit: Stuart Hay – ANU.

During the misty years following the discovery of the Flores hobbits, one of the most promising hypotheses explaining their origin posited that the 1.1-meter-tall creatures evolved from Homo erectus populations settled in Asia. Homo erectus is basically the first hominid that looked like a human.

Homo erectus had a long tenure. The earliest Homo erectus fossils are dated to roughly 1.8 million years ago, while the youngest fossils assigned to this species date to roughly 300 thousand years ago. The stature of Homo erectus is considered to be very similar to that of living humans having a hindlimb that’s much longer than in earlier forms. Its skulls were generally thicker and more massively built than those of H. sapiens, but all other features point to striking similarities between the two species.

Initial surveys of H. floresiensis remains suggested it was a direct descendant of H. erectus, but some critics have pointed out the evidence presented thus far is inconclusive. To get to the bottom of things Australian researchers led by Dr. Debbie Argue from the Australian National University examined 133 cranial, postcranial, mandibular, and dental remains coming from H. floresiensis but also other hominid species. No other study collected or examined these many samples before and previously scientists focused on finding the best match for the skull and lower jaw only.

A digital reconstruction of the face of H. floresis. Credit: ANU.

A digital reconstruction of the face of H. floresiensis. Credit: ANU.

The examination showed that H. floresiensis doesn’t share that as many features with H. erectus as some believed. Instead, the hobbits seem much more similar to Homo habilis, the earliest representative of the Homo genus which lived between 1.6 million and 2.4 million years ago.

“The analyses show that on the family tree, Homo floresiensis was likely a sister species of Homo habilis. It means these two shared a common ancestor,” Dr Argue said.

“It’s possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa then evolved into Homo floresiensis somewhere.”

Virtual endocast of H. floresiensis (left) vs H. sapiens (right). Credit: rofessor Peter Brown, University of New England.

Virtual endocast of H. floresiensis (left) vs H. sapiens (right). Credit: rofessor Peter Brown, University of New England.

The findings refute the idea that the hobbits evolved from Asian Homo erectus which presumably underwent island dwarfing. Instead, a counter-hypothesis which suggests the hobbits evolved from an earlier ancestor in Africa, who was most likely Homo habilis, seems more favorable. The hobbits either evolved in Africa then migrated to Asia where they eventually reached the island of Flores in Indonesia or the common ancestor migrated from Africa then evolved into H. floresiensis somewhere on route or on the famous island itself.

The biggest takeaway is that H. floresiensis was far more primitive than previously thought, though it went extinct less than 15,000 years ago.

“We can be 99 per cent sure it’s not related to Homo erectus, and nearly 100 per cent chance it isn’t a malformed Homo sapiens,” said Professor Mike Lee of Flinders University and the South Australian Museum, and co-author of the study published in the Journal of Human Evolution.

An artist impression of how Homo naledi must have looked like based on skull scans. Image: Mark Thiessen/National Geographic

New human ancestor, Homo naledi, discovered in a hidden pit, deep inside a South African cave

A daring team of researchers squeezed themselves through a long vertical chute and descended some 40 meters beneath the surface. It was here inside the Rising Star cave, located in the Cradle of Humankind World Heritage Site about 30 miles (50 kilometers) northwest of Johannesburg in South Africa, that the researchers discovered one of the most important collection of hominins in the world – 1,500 bone fragments belonging to 15 skeletons. The remains clearly belonged to a human ancestor, and the team involved claims we’re talking, in fact, about a totally new hominin.

An artist impression of how Homo naledi must have looked like based on skull scans. Image:  Mark Thiessen/National Geographic

An artist impression of how Homo naledi must have looked like based on skull scans. Image: Mark Thiessen/National Geographic

The new species, which has yet to be confirmed (the researchers broke the news before intense scrutiny), was named Homo naledi, after naledi which means “star” in Sesotho, a local South African language. At first glance it looks like a Homo Erectus, a famous human ancestor which lived 1.9 million years and was first discovered in the 1800s when Darwin’s theory of evolution was still met with widespread skepticism. However, Lee Berger, a paleoanthropologist at the University of the Witwatersrand in Johannesburg and the lead researcher, thinks his team has actually come across a new species – showing both primitive and modern features, ape-like and human at the same time. More literally, Berger describes Homo naledi as “long-legged”, “pinheaded” and “gangly”.

“Pinheaded” is a proper adjective. Homo naledi’s brain was the size of a gorilla’s or an orange. The rest of its body was also primitive, sporting an ape-like thorax and curved fingers suggesting it spent most of its time in trees. Other features are more modern, though: the hands were capable of shaping tools, the feet and ankles support upright walking, the researchers report in eLife (paper 1 and 2).

Researchers unearthed fossils from at least 15 individuals belonging to the newfound species, Homo naledi. Image: Berger et al. eLife 2015;

Researchers unearthed fossils from at least 15 individuals belonging to the newfound species, Homo naledi. Image: Berger et al. eLife 2015;

The remains have yet to be dated since the bones weren’t trapped in any sediment. The only viable dating method is radiocarbon dating which would ruin the bones. Once all the collection is thoroughly described and documented, the dating will also follow. For now, Berger suspects the remains are about 3 million years old judging from the morphology of Homo naledi which should be pre-Homo Erectus in the evolutionary tree.

 

The team lays out fossils of Homo naledi at the University of the Witwatersrand’s Evolutionary Studies Institute. Photograph: Robert Clark/National Geographic

The team lays out fossils of Homo naledi at the University of the Witwatersrand’s Evolutionary Studies Institute. Photograph: Robert Clark/National Geographic

This was no easy find. Berger first found in the narrow shaft entrance by accident while exploring the Rising Star cave in 2013. He threw a tethered GoPro camera and was startled to find he had recorded a skull. Within a month, he had assembled a team of 60 researchers to commence exploring, including six female researchers who had to be extra slim and tiny to fit through. Only these women could go down the shaft, descend the narrow entrance and recover the bones from the pit – some 1,500 bones and hundreds of teeth. A few thousand more are still there, according to Berger and will be retrieved in a follow-up expedition.

“If this is an ancient species, like a coelacanthe, that has come down through time and is only tens of thousands, or hundreds of thousands of years old, it means that during that time we had a complex species wandering around Africa, perhaps making tools. That would make archaeology very difficult, because we aren’t going to know who made what,” Berger said.

Researchers also suggest that the pit may have actually been a burial site, meaning the bodies were purposely thrown there. “We have, after eliminating all of the probable, come to the conclusion that Homo naledi was utilising this chamber in a ritualised fashion to deliberately dispose of its dead,” Berger said. It’s unlikely, Berger believes, that so many individuals went through the narrow shaft into pitch black darkness and then got stuck or died when water fell in or the cave itself collapsed.

While the findings seem extraordinary, other researchers are more cautious. “Intentional disposal of rotting corpses by fellow pinheads makes a nice headline, but seems like a stretch to me,” said William Jungers, an anthropologist at Stony Brook School of Medicine in New York for The Guardian. Jungers isn’t convinced that the remains evidence a novel species either. These could be an isolated population of Homo Erectus, a ‘relic’ version which would make it more of an oddity and less of a ‘game-changer’.

This was a National Geographic-funded project.

Oldest ever engraving discovered on 500,000-year-old shell

Archaeologists have identified the oldest engraving known to mankind – a 500,000 shell scratched by a human ancestor.

Detail of the engraving on fossil Pseudodon shell (DUB1006-fL) from Trinil.
Credit: Wim Lustenhouwer, VU University

In 2007, Stephen Munro was a graduate student in archaeology; while he was studying some shells from Java, Indonesia, he had the shock of his life: he found that one shell had a pattern of zig-zag lines inscribed into it. Using microscopy, Francesco d’Errico, an archaeologist at the University of Bordeaux showed that the marks had been etched in one session, by one person using a sharp tool.

“I almost fell off my chair,” Munro says. That’s because the oldest known engravings date back 100,000 years and were made by modern humans—the only species thought to be capable of making abstract designs.

But 500,000 years ago (the age of the shell), there were no modern humans around. However, Homo Erectus was around. Homo Erectus is an extinct species of hominid that lived throughout from about 1.9 million years ago to 143,000 years ago. The species originated in Africa, but spread as far as Georgia, India, Sri Lanka, China and (of course) Java. That’s right, Homo erectus on Java was already using shells of freshwater mussels as tools half a million years ago, and as a ‘canvas’ for an engraving.

“Until this discovery, it was assumed that comparable engravings were only made by modern humans (Homo sapiens) in Africa, starting about 100,000 years ago,” says lead author José Joordens, researcher at the Faculty of Archaeology at Leiden University.

shells

Note the zig-zag graving. Image credits: WIM LUSTENHOUWER/VU UNIVERSITY AMSTERDAM

This is significant because many psychologists believe that geometric engravings are a sure sign of modern cognitive abilities, and only modern humans (Homo Sapiens) were thought to have cognitive abilities. This also means that Homo Erectus didn’t only made tools from stone, as was previously believed, but also used shells for this. They know shells were used as tools because one of them has a smooth and polished edge, which indicates that it was used as a tool for cutting or scraping.

Homo Erectus was pretty creative with the shells – first of all, they opened them by drilling a hole through the shell using a hard, pointed object (possibly a shark’s tooth) at exactly the spot where the muscle that keeps the shell closed is attached. Archaeologists have found many shells like this. If you damage or destroy these mussels, they open right up. If these findings are confirmed, then this means that after opening and eating them, Homo Erectus also used the shells as tools and as canvas for doodling.

“The precision with which these early humans worked indicates great dexterity and detailed knowledge of mollusc anatomy,” says Frank Wesselingh, a researcher and expert on fossil shells at Naturalis.

A team of 21 researchers analyzed the shells and associated sediments. The engraved geometrical pattern on one of the shells came as a total surprise. You need light coming from a particular angle to see the drawing, which is clearly older than the weathering processes on the shell arising from fossilization. Researchers at the VU University Amsterdam dated the shells and found that their age is between 430,000 and  540,000 years old. Could it be a hoax? The answer is almost beyond the shadow of a doubt: No, it’s not a hoax. This type of dating is usually very accurate and furthermore, Robin Dennell, an archaeologist at the University of Exeter in the United Kingdom revealed that the interiors of the grooves were smooth and rounded, not “jagged and sharp-edged” as you’d expect with modern engravings.

Image credits: WIM LUSTENHOUWER/VU UNIVERSITY AMSTERDAM

“I raised the scenario that one of Dubois’s workforce might have been bored and engraved a shell over lunch time”, he joked, before explaining how we know this is not the case.

What’s interesting to note is that the shells have been in a museum collection for quite some time now, and this spectacular discovery was just now made.

“It’s fantastic that this engraved shell has been discovered in a museum collection where it has been held for more than a hundred years. I can imagine people may be wondering whether this can be seen as a form of early art,” says Wil Roebroeks, Professor of Palaeolithic Archaeology at Leiden University. He was able to finance this long-term research with his NWO Spinoza Prize. “At the moment we have no clue about the meaning or purpose of this engraving.”

Can we really call this art? I don’t really know, but one thing’s for sure – we have to reevaluate our knowledge about the cognitive abilities of humanity’s ancestors.

Journal References:

  1. Joordens J.C.A., d’Errico F., Wesselingh F.P., Munro S. de Vos, J., Wallinga, J. Ankjærgaard, C., Reimann, T., Wijbrans, J.R., Kuiper K.F., Mücher H.J., Coqueugniot, H., Prié, H.V., Joosten, I., van Os, B., Schulp, A.S., Panuel, M., van der Haas V., Lustenhouwer W., Reijmer J.J.G., Roebroeks, W. Homo erectus at Trinil on Java used shells for tool production and engraving. Nature, December 2014 DOI: 10.1038/nature19362
  2. Josephine C. A. Joordens, Francesco d’Errico, Frank P. Wesselingh, Stephen Munro, John de Vos, Jakob Wallinga, Christina Ankjærgaard, Tony Reimann, Jan R. Wijbrans, Klaudia F. Kuiper, Herman J. Mücher, Hélène Coqueugniot, Vincent Prié, Ineke Joosten, Bertil van Os, Anne S. Schulp, Michel Panuel, Victoria van der Haas, Wim Lustenhouwer, John J. G. Reijmer, Wil Roebroeks. Homo erectus at Trinil on Java used shells for tool production and engraving. Nature, 2014; DOI: 10.1038/nature13962

Skull suggests three hominid species were just one

A new, controversial analysis of a skull suggests that Homo habilis, Homo rudolfensis and Homo erectus were in fact the same species, something which would force scientists rewrite a big page of anthropology.

skull

Researchers compared the anatomical features of the of a 1.8-million-year-old fossil skull with those of four other skulls from the same excavation site at Dmanisi, Georgia; the skull, informally named “Skull 5” is “the most complete skull of an adult from this date”. It’s very interesting to observe the differences between all the skulls found in the same place, from the same era:

“The Dmanisi skulls look quite different from one another”, Zollikofer says, “so it’s tempting to publish them as different species. Yet we know that these individuals came from the same location and the same geological time, so they could, in principle, represent a single population of a single species.”

Taking that theory and testing it with existing data, the statistics seem to add up.For example, the volume of skull 5 is only about 75% that of the largest skull unearthed at the Dmanisi site — a disparity that may seem large but that falls within the variation seen among modern humans and within chimpanzees. The variation also seems to fit within the range of previous findings from the same era.

“Like so many finds, [the skull] adds to what we know, but does not necessarily clarify or simplify things,” says Robert Foley, a paleoanthropologist at the University of Cambridge, UK. Nevertheless, he notes, the results of the new analysis must change the way scientists think about the nature and magnitude of anatomical variation in early Homo.

If the three species were in fact just one, then H. habilis and H. ruldofensis would be subsumed into H. erectus – but there’s a lot of criticism aimed at that idea. First of all, cramming the three species which inhabited an area (at least) from Africa to Indonesia seems a little far fetched. Fred Spoor, a palaeontologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany is not convinced by this new theory. He believes that the statistical analysis used to study cranial differences are not relevant, and instead, researchers should have analysed pecific anatomical traits, such as the height of the braincase or the diameter of the eye socket, which are the most common characteristics used to frame species.

Via Nature.

Required daily feeding time for hominin and great ape species to afford combinations of MBD and total number of brain neurons. Notice that H. heidelbergensis, H. neanderthalensis, and H. sapiens fall well over the viability curve for 8 h/d of feeding if they had a raw foods diet similar to extant nonhuman primates. (c) Fonseca-Azevedo and Herculano-Houzel

Cooking food helped early humans grow bigger brains

The pyramids, art, all of the world’s great inventions, literary works, just about any valuable intellectual work can be traced back to food – cooked food. If you care to go as far back as our very roots, that is. Previous research showed that cooked food made it easier and more efficient for our guts to absorb calories more rapidly, which helped increase the brains of our early ancestors. A new research by neuroscientists at  the Federal University of Rio de Janeiro in Brazil found that humans nowadays would need to eat 9 hours non-stop to get enough energy from unprocessed raw food alone to support our large brains.

“If you eat only raw food, there are not enough hours in the day to get enough calories to build such a large brain,” says Suzana Herculano-Houzel, a neuroscientist at the Federal University of Rio de Janeiro in Brazil who is co-author of the report. “We can afford more neurons, thanks to cooking.”

Humans have roughly three times as many neurons (86 billion) than our close primate cousins, like gorillas (33 billion) or chimpanzees (28 billion). The Brazilian scientists found that the number of neurons is directly linked to brain size, as well as to the amount of energy needed to feed the brain. Thus, humans need brains consume 20% of our body’s energy when resting, compared with 9% in other primates – a hefty cost. This begged the question, however: from where did our ancestors get all this extra energy to grow such a large brain in a relatively short evolutionary time frame?

Required daily feeding time for hominin and great ape species to afford combinations of MBD and total number of brain neurons. Notice that H. heidelbergensis, H. neanderthalensis, and H. sapiens fall well over the viability curve for 8 h/d of feeding if they had a raw foods diet similar to extant nonhuman primates. (c) Fonseca-Azevedo and Herculano-Houzel

Required daily feeding time for hominin and great ape species to
afford combinations of MBD and total number of brain neurons. Notice that
H. heidelbergensis, H. neanderthalensis, and H. sapiens fall well over the
viability curve for 8 h/d of feeding if they had a raw foods diet similar to
extant nonhuman primates. (c) Fonseca-Azevedo and Herculano-Houzel

The answer is cooked food, according to the researchers. Back in the 1990s, Harvard University primatologist Richard Wrangham asserted, in a now famous thesis, that the human lineage embarked on an explosive growth of the brain some 1.6 to 1.8 million years ago when Homo Erectus started cooking food. Wrangham claimed that processed food is more efficiently absorbed in the body, significantly increasing the relative energy intake compared to digesting raw food. Follow-up studies at the time demonstrated that rodents or pythons grow faster and bigger when they eat cooked meat instead of raw meat, and that it takes less energy to digest cooked meat than raw meat.

You’d need to eat raw food for 9 hours without rest in order to get the same energy kick

 A comparison of the frontal lobes (colored) in human and several non-human primate species. The evolutionary relationships among the species are indicated by the connecting lines. Semendeferi and colleagues5 found that human frontal lobes are not disproportionately larger than predicted for a primate brain of its size. (Figure courtesy of K. Semendeferi and H. Damasio from a different  research - Nature Neuroscience  5, 190 - 192 (2002)  doi:10.1038/nn0302-190).

A comparison of the frontal lobes (colored) in human and several non-human primate species. The evolutionary relationships among the species are indicated by the connecting lines. Semendeferi and colleagues5 found that human frontal lobes are not disproportionately larger than predicted for a primate brain of its size. (Figure courtesy of K. Semendeferi and H. Damasio from a different research – Nature Neuroscience 5, 190 – 192 (2002) doi:10.1038/nn0302-190).

For the present research, the neuroscientists calculated how many hours per day humans and other primates need to eat raw food in order to support their current brains and body size. They found that it would take 8.8 hours for gorillas; 7.8 hours for orangutans; 7.3 hours for chimps; and 9.3 hours for our species, H. sapiens. Worth noting is the fact that raw food in this case, refers to that found in the wild, not processed raw food that humans typically prepare with blenders and add protein and other nutrients to.

 “The reason we have more neurons than any other animal alive is that cooking allowed this qualitative change—this step increase in brain size,” she says. “By cooking, we managed to circumvent the limitation of how much we can eat in a day.”

This study shows “that an ape could not achieve a brain as big as in recent humans while maintaining a typical ape diet,” Wrangham says.

Not all researchers are convinced however that cooking food sparked the brain growth explosion of our ancestors. That may very well be so, believes Paleoanthropologist Robert Martin of The Field Museum in Chicago, Illinois, who agrees that the present paper is the first to provide tangible evidence of metabolic limitations, but who goes on to say that whether our ancestors began cooking over a fire later, when the brain went through a second major growth spurt about 600,000 years ago or during H. Erectus is still unclear. The earliest evidence of hominid fire control found thus far has been dated from 800,000 years ago, and  regular use of fire for cooking doesn’t become widespread until more recently.

“Gorillas are stuck with this limitation of how much they can eat in a day; orangutans are stuck there; H. erectuswould be stuck there if they had not invented cooking,” Herculano-Houzel said. “The more I think about it, the more I bow to my kitchen. It’s the reason we are here.”

Findings were published in the journal Proceedings of the National Academy of Sciences

source: ScienceMag

Fossil hints at distant relatives of our ancestors, deepens mystery

Our family tree may be much more complex than we know – it may have sprouted some long lost branches which go back some 2 million years.

A messy family tree

Image provided by National Geographic and Nature

A team led by Meave Leakey, daughter-in-law of distinguished scientist Louis Leakey found facial and jaw bones from three specimens that led them to believe our human ancestors had plenty of company from different human-like species. The bones most definitely don’t come from our ancestor, Homo Erectus, and they most likely come from a distant cousin of Homo Erectus, with who they share the same ancestors.

But other archaeologists and anthropologists aren’t buying this theory: they believe it’s jumping to conclusions based on way too little evidence. Either way, this is a continuation of a long-running argument in anthropology about the earliest members of our own genus, or class, called Homo – a family tree which is becoming more messy and complicated.

The thing is, while these findings look drastically different from those of modern humans, they closely resemble an enigmatic, nearly complete skull found 40 years ago that paleoanthropologists have been trying ever since to fit into the family tree. To add even more drama to the table, that skeleton was found by the Leakeys as well.

The cradle of humanity

Meave Leakey and Susan Anton

East Africa is though to be the seat of human origins, and at the time in which Homo Erectus began its ascension, it was “quite a crowded place with multiple species,” said Fred Spoor of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, a co-author of a report describing the finds. Homo Habilis (which means ‘handy man’) was another genus known for creating primitive stone blades. Another, more primitive species, Paranthropus bosei, also lived in the region at the time.

But the new finds, and the mystery skull, which may or may not be the same species, clearly don’t belong to any groups. The face is too flat, falling down like a cliff from brow to chin, while the teeth are straight instead of arching, like with Homo Erectus. The molars are also very large, and the brain was very big for the time, albeit it measured just half of that of a modern human.

A 40 year old mystery

The mystery skull found 40 years ago may hold a key role in this controversy. The skull wasn’t given a name, and is only identified by a number – KNM-ER 1470. In the 40 years since it was found, members of the Leakey family, all involved in archaeology and anthropology, have been trying to find anything resembling it, but they have been unsuccessful – until now. Thus, a new spark flames the debate, between those who believe they are members of a new species, and those who believe the specimens are merely deformed examples of other, known, species.

“There just hasn’t been any evidence one way or another,” said Susan Anton of New York University, who collaborated with Meave Leaky in describing the new fossils.

Rick Potts, current director of Smithsonian Institution’s human origins program is firmly convinced that the new findings represent a new species. Potts, who was not involved in the study, added:

“There will still be controversy over what to call these things. The old picture of human evolution heading in a straight line — where an early species gave rise to a more advanced species and so on, until finally reaching modern humans — is all but defunct.”

“At the moment, all we’re doing is classifying heads,” said Bernard Wood, a paleoanthropologist at George Washington University who studied the mystery skull in the early 1990s and declared it likely represented a new species. “It will be a different ballgame when we can match heads with limbs. There are limb bones, but with no heads.”

It’s still unclear if these species interacted with each other, or even more, if they interbred.

Source

Ancient human tool use much earlier than thought!

Humans might have started using sophisticated tools some 1.76 million years ago, much earlier than previously believed. This has been suggested by the discovery of hand axes from that period which belong to the complex Archeulean culture. This could also change what we believe about the period when humans started leaving Africa.

Anthropologists consider the Acheulean hand axes to be the culture of our ancestor Homo erectus, and we know H. erectus first evolved around 1.8 or 2 million years ago,” study researcher Christopher Lepre, of Columbia University, said. “I think most researchers were anticipating that older stone axes would be found.” And now they’ve found them.

Several of these hand axes belonging to the Archeulean were found; they were built from chipped volcanic rock from a nearby stream, were found at a site on the shore of Lake Turkana in Kenya. They found that the axes have different levels of sophistication – for that period, that is.

“There’s not a tremendous amount of diligence that goes into making the Oldowan tools, you can say they are kind of haphazardly made,” Lepre said. “It’s pretty simple in terms of the makers were bashing stones together to make sharp edges.”

The data indicates that there were at least 2 tool-using hominids living in Africa 1.76 million years ago, but what’s still a mystery is how these tools left Africa, because the Archeulean culture and their tools didn’t leave Africa until about 1 million years ago, and it is currently believed that Homo Erectus colonized Europe 1.5 million years ago.

This could mean two things: either that the Homo Erectus that migrated to Europe didn’t develop Archeulean technologies for half million years, or that Homo Erectus wasn’t the species who created those axes at all. They could have been developed by the lesser evolved Homo habilis. Either way, so far, something doesn’t seem to add up.

600,000 year old discovered tool mill provies new Homo Erectus insights

Bust of Peking Man on permanent display at Zhoukoudian, China

We now know that pre-modern human tool use dates back far beyond we previously might have thought, each discovery proving that our early ancestors showed sign of intelligence and early social evolution. A recent finding in central China of a prehistoric tool mill dating back 600,000 years ago used by Homo Erectus in the Lushi Basin, South Luo River, supports this hypothesis. The discovery was dated using pedostratigraphic analysis, optically stimulated luminescence, and magnetostratigraphic analysis which authenticated the aforementioned period.

Basically, the Lushi Basin site shows that Home Erectus actually had some sort of tool factory (100 stone implements were found), where flake and core technology, similar to other tools used by Home Erectus and found in China at other sites, proving that they actually were organized at a greater level of sophistication then previously thought.

Prof. Huayu Lu has co-authored a thesis on the finding with researchers from the Henan archeological institute and La Trobe University of Australia. The thesis was published on the latest issue of Journal of Human Evolution, where you can read more about the discovery (for 19.95$ unfortunately).