Neanderthals may have been infected by diseases carried out of Africa by humans
Aril 10, 2016
A new study suggests that Neanderthals across Europe may well have been infected with diseases carried out of Africa by waves of anatomically modern humans, or Homo sapiens. As both were species of hominin, it would have been easier for pathogens to jump populations, say researchers. This might have contributed to the demise of Neanderthals.
Researchers from the universities of Cambridge and Oxford Brookes have reviewed the latest evidence gleaned from pathogen genomes and DNA from ancient bones, and concluded that some infectious diseases are likely to be many thousands of years older than previously believed.
There is evidence that our ancestors interbred with Neanderthals and exchanged genes associated with disease. There is also evidence that viruses moved into humans from other hominins while still in Africa. So, the researchers argue, it makes sense to assume that humans could, in turn, pass disease to Neanderthals, and that - if we were mating with them - we probably did.
Dr Charlotte Houldcroft, from Cambridge's Division of Biological Anthropology, says that many of the infections likely to have passed from humans to Neanderthals - such as tapeworm, tuberculosis, stomach ulcers and types of herpes - are chronic diseases that would have weakened the hunter-gathering Neanderthals, making them less fit and able to find food, which could have catalysed extinction of the species.
"Humans migrating out of Africa would have been a significant reservoir of tropical diseases," says Houldcroft. "For the Neanderthal population of Eurasia, adapted to that geographical infectious disease environment, exposure to new pathogens carried out of Africa may have been catastrophic."
"However, it is unlikely to have been similar to Columbus bringing disease into America and decimating native populations. It's more likely that small bands of Neanderthals each had their own infection disasters, weakening the group and tipping the balance against survival," says Houldcroft.
New techniques developed in the last few years mean researchers can now peer into the distant past of modern disease by unravelling its genetic code, as well as extracting DNA from fossils of some of our earliest ancestors to detect traces of disease.
In a paper published today in the American Journal of Physical Anthropology, Houldcroft, who also studies modern infections at Great Ormond Street Hospital, and Dr Simon Underdown, a researcher in human evolution from Oxford Brookes University, write that genetic data shows many infectious diseases have been "co-evolving with humans and our ancestors for tens of thousands to millions of years".
The longstanding view of infectious disease is that it exploded with the dawning of agriculture some 8,000 years ago, as increasingly dense and sedentary human populations coexisted with livestock, creating a perfect storm for disease to spread. The researchers say the latest evidence suggests disease had a much longer "burn in period" that pre-dates agriculture.
In fact, they say that many diseases traditionally thought to be 'zoonoses', transferred from herd animals into humans, such as tuberculosis, were actually transmitted into the livestock by humans in the first place.
"We are beginning to see evidence that environmental bacteria were the likely ancestors of many pathogens that caused disease during the advent of agriculture, and that they initially passed from humans into their animals," says Houldcroft.
"Hunter-gatherers lived in small foraging groups. Neanderthals lived in groups of between 15-30 members, for example. So disease would have broken out sporadically, but have been unable to spread very far. Once agriculture came along, these diseases had the perfect conditions to explode, but they were already around."
There is as yet no hard evidence of infectious disease transmission between humans and Neanderthals; however, considering the overlap in time and geography, and not least the evidence of interbreeding, Houldcroft and Underdown say that it must have occurred.
Neanderthals would have adapted to the diseases of their European environment. There is evidence that humans benefited from receiving genetic components through interbreeding that protected them from some of these: types of bacterial sepsis - blood poisoning occurring from infected wounds - and encephalitis caught from ticks that inhabit Siberian forests.
In turn, the humans, unlike Neanderthals, would have been adapted to African diseases, which they would have brought with them during waves of expansion into Europe and Asia.
The researchers describe Helicobacter pylori, a bacterium that causes stomach ulcers, as a prime candidate for a disease that humans may have passed to Neanderthals. It is estimated to have first infected humans in Africa 88 to 116 thousand years ago, and arrived in Europe after 52,000 years ago. The most recent evidence suggests Neanderthals died out around 40,000 years ago.
Another candidate is herpes simplex 2, the virus which causes genital herpes. There is evidence preserved in the genome of this disease that suggests it was transmitted to humans in Africa 1.6 million years ago from another, currently unknown hominin species that in turn acquired it from chimpanzees.
"The 'intermediate' hominin that bridged the virus between chimps and humans shows that diseases could leap between hominin species. The herpes virus is transmitted sexually and through saliva. As we now know that humans bred with Neanderthals, and we all carry 2-5% of Neanderthal DNA as a result, it makes sense to assume that, along with bodily fluids, humans and Neanderthals transferred diseases," says Houldcroft.
Recent theories for the cause of Neanderthal extinction range from climate change to an early human alliance with wolves resulting in domination of the food chain. "It is probable that a combination of factors caused the demise of Neanderthals," says Houldcroft, "and the evidence is building that spread of disease was an important one."
Dr. Dobieslawa Baginska checks GPS coordinates of the Hag Magid site. Photo by Dr. Krzysztof Grzymski
When vineyards bloomed in Sudan...
March 25, 2016
Poznan archaeologists discovered settlements, towns and cemeteries from the Middle Ages during research in northern Sudan, in the area of the Letti Basin. Now, researchers intend to examine one of these places in more detail.
In the mid-seventh century, Egypt was conquered by Muslim armies. The pressure of the invading army, advancing south along the Nile Valley, stopped the Christian kingdom of Makuria. The relics of this civilization have been discovered by Poznan archaeologists in the area of the Letti Basin, about 350 km north of Khartoum. Makuria was a powerful kingdom, which existed from the sixth to the fourteenth century between II and V cataracts of the Nile. For several centuries its power reached even farther north almost to the modern Aswan.
"The southern part of the kingdom of Makuria is fairly well known thanks to the excavations conducted by the Centre of Mediterranean Archaeology of the University of Warsaw in Ghazali, Banganarti and Dongola - the latter was the capital of the kingdom. The northern is still terra incognita" - told PAP Dr. Dobieslawa Baginska from the Archaeological Museum in Poznan, initiator of the research project in the Letti Basin.
In autumn 2015, scientists carried out extensive reconnaissance in the Letti Basin, in the area of approx. 150 km2 - this area was previously very poorly surveyed by archaeologists. Several sites in the area were reported by Krzysztof Grzymski of the Royal Ontario Museum.
Now archaeologists confirmed the presence of previously known sites, but also discovered a number of previously unknown relics of settlements and cemeteries, mainly from the period of the kingdom of Makuria. These findings confirm the reports of the Arab travellers - more than 1,000 years ago, the Kingdom of Makuria was a rich country, its power could compete with the Arab invaders, attacking from Egypt. The Letti Basin was an economic and cultural base for the capital of Makuria - Dongola.
"Hag Magid is especially promising for us - it is a huge elevation with an area of over a hectare, on the surface of which we found medieval columns, details of architecture and thousands of fragments of pottery" - said Dr. Baginska.
The researcher suspects that under the sand are well-preserved remains of a church, monastery and other structures from before one thousand years. To confirm this, she plans to perform non-invasive, geophysical surveys, which will tell what hides under the surface without having to drive a shovel.
"Structures hiding beneath the sand are from the same period and belong to the same cultural circle as the basilica discovered decades ago by Prof. Kazimierz Michalowski in Faras on - paintings found then went to Khartoum and Warsaw, where they are on display in museums" - said Dr. Baginska.
The researcher is cautious in her estimates whether the importance of discoveries at Hag Magid will match those in Faras, but preliminary survey is promising - she believes that it is possible to make spectacular discoveries in the form of interior decorated with paintings, stone architectural details and decorative floors.
"Importantly, in contrast to Egypt and other countries in the Middle East, where it is not possible to acquire even part of the monuments from excavations, the Sudanese authorities are open to this type of solution. This means that tangible results of excavations will not only increase enhance knowledge, but also museum collections. Even the monuments found on the surface of our site of interest have a large exhibition value" - noted Dr Baginska. Currently, the researcher is looking for funds to finance the fieldwork and geophysical surveys in this year's archaeological season, which is planned for autumn.
Ceramic dishes resting on the surface of the hill at Hag Magid come from VII-XIII centuries. The hill has a height of approximately 6 meters; archaeologists believe that it formed as a result of hundreds of years of settlement - subsequent structures were erected in the same place. That created a huge hill consisting of relics of buildings, mud bricks, stone details and tons of pottery.
Scientists know that more than 1,000 years ago the Letti Basin looked very different than today - now sandy desert dominates. "During the heyday of the kingdom of Makuria, a canal ran near Hag Magid and watered the whole area. It is worth noting that vines were cultivated here on a large scale, and wine was produced, as we read in the reports of Arab travellers who ventured into this Christian kingdom" - said Dr. Baginska.
Therefore, the goal of scientists will also be to study the historic climate and crops - until now archaeologists working in Sudan did not research this topic.
"We are also concerned that Hag Magid could be buried by shifting sand dunes - thus we would lose the opportunity of studying it for the next few decades" - concluded Dr. Baginska.
Australopithecus fossils found east of the Great Rift Valley
March 25, 2016
New fossils from Kenya suggest that an early hominid species - Australopithecus afarensis - lived far eastward beyond the Great Rift Valley and much farther than previously thought. An international team of paleontologists led by Emma Mbua of Mount Kenya University and Masato Nakatsukasa of Kyoto University report findings of fossilized teeth and forearm bone from an adult male and two infant A. afarensis from an exposure eroded by the Kantis River in Ongata-Rongai, a settlement in the outskirts of Nairobi.
"So far, all other A. afarensis fossils had been identified from the center of the Rift Valley," explains Nakatsukasa. "A previous Australopithecus bahrelghazali discovery in Chad confirmed that our hominid ancestor's distribution covered central Africa, but this was the first time an Australopithecus fossil has been found east of the Rift Valley. This has important implications for what we understand about our ancestor's distribution range, namely that Australopithecus could have covered a much greater area by this age."
A. afarensis is believed to have lived 3,700,000-3,000,000 years ago, as characterized by fossils like "Lucy" from Ethiopia.
Stable isotope analysis revealed that the Kantis region was humid, but had a plain-like environment with fewer trees compared to other sites in the Great Rift Valley where A. afaransis fossils had previously appeared. "The hominid must have discovered suitable habitats in the Kenyan highlands. It seems that A. afaransis was good at adapting to varying environments," notes Nakatsukasa.
The team's survey also turned up masses of mammal fossils, including a few that probably belong to new species of bovids or baboons.
The authors write that the Kantis site was first noted in a 1991 geological survey. At that time, a farmer said that he and his family had come across fossilized bones from Kantis in the 1970s, although they did not recognize their importance. Following airing of Kenyan television programs on paleontological research, locals gradually started to appreciate the fossils. Since then, Kantis and other sites have been identified thanks to fossil notifications from the local population.
The team welcomes this achievement not only for its academic implications, but also for the benefits to the local community. "Kantis is in the vicinity of Nairobi, a major city," said Nakatsukasa. "We hope that the discovery of the new site and the fossils will aid in increasing tourism, and in improving educational awareness of the local community."
In this undated photo made available by Blue Water Recoveries company on Tuesday, March 15, 2016, divers excavate the wreck site of the Portuguese explorer Vasco da Gama's ship, Esmeralda which sank in a storm in May 1503 off the coast of Al Hallaniyah island in Oman's Dhofar region. (Blue Water Recoveries company via AP)
Site of 1503 shipwreck tied to Vasco da Gama found off Oman
March 15, 2016
The 500-year-old wreckage of Portuguese ship piloted by an uncle of explorer Vasco da Gama has been found off the coast of Oman, archaeologists said Tuesday, a discovery that included the recovery of an incredibly rare coin.
The Esmeralda sank during a violent storm near al-Hallaniyah Island in the Indian Ocean in May 1503, killing commander Vicente Sodre and all those aboard.
Beginning in 2013, a team from the British company Blue Water Recoveries and the Oman Ministry of Heritage and Culture explored a site in the island's Ghubbat ar Rahib Bay. They later determined the debris found there came from the long-missing ship, one of two lost in the storm from da Gama's second voyage to India.
Among the stone shot, ceramics, a bell and other debris, divers discovered an incredibly rare silver coin called an Indio, of which only one other is known to exist today, said David L. Mearns, the director of Blue Water Recoveries. The coins were forged in 1499 after da Gama's first voyage to India, which helps date the wreckage, he said.
"That was an amazing discovery," Mearns said. "It was like a thing you read about in a Hollywood story."
The archaeologists announced their findings in an article published Tuesday by The International Journal of Nautical Archaeology.
Ayoub al-Busaidi, the supervisor of marine archaeology at the Oman Ministry of Heritage and Culture, said this marked the first underwater excavation carried out by his country. He said it inspired officials to continue to explore the waters around the sultanate for other finds.
"Oman is now looking at outside archives to read about the relationships and trade between Oman and the outside" world, al-Busaidi said.
Early human habitat recreated for first time
March 10, 2016
Scientists have pieced together an early human habitat for the first time, and life was no picnic 1.8 million years ago.
Our human ancestors, who looked like a cross between apes and modern humans, had access to food, water and shady shelter at a site in Olduvai Gorge, Tanzania. They even had lots of stone tools with sharp edges, said Gail M. Ashley, a professor in the Rutgers Department of Earth and Planetary Sciences in the School of Arts and Sciences.
But "it was tough living," she said. "It was a very stressful life because they were in continual competition with carnivores for their food."
During years of work, Ashley and other researchers carefully reconstructed an early human landscape on a fine scale, using plant and other evidence collected at the sprawling site. Their pioneering work was published recently in the Proceedings of the National Academy of Sciences.
The landscape reconstruction will help paleoanthropologists develop ideas and models on what early humans were like, how they lived, how they got their food (especially protein), what they ate and drank and their behavior, Ashley said.
Famous paleoanthropologist Mary Leakey discovered the site in 1959 and uncovered thousands of animal bones and stone tools. Through exhaustive excavations in the last decade, Ashley, other scientists and students collected numerous soil samples and studied them via carbon isotope analysis.
The landscape, it turned out, had a freshwater spring, wetlands and woodland as well as grasslands.
"We were able to map out what the plants were on the landscape with respect to where the humans and their stone tools were found," Ashley said. "That's never been done before. Mapping was done by analyzing the soils in one geological bed, and in that bed there were bones of two different hominin species."
The two species of hominins, or early humans, are Paranthropus boisei - robust and pretty small-brained - and Homo habilis, a lighter-boned species. Homo habilis had a bigger brain and was more in sync with our human evolutionary tree, according to Ashley.
Both species were about 4.5 to 5.5 feet tall, and their lifespan was likely about 30 to 40 years.
Through their research, the scientists learned that the shady woodland had palm and acacia trees. They don't think the hominins camped there. But based on the high concentration of bones, the primates probably obtained carcasses elsewhere and ate the meat in the woods for safety, Ashley said.
In a surprising twist, a layer of volcanic ash covered the site's surface, nicely preserving the bones and organic matter, said Ashley, who has conducted research in the area since 1994.
"Think about it as a Pompeii-like event where you had a volcanic eruption," she said, noting that a volcano is about 10 miles from the site. The eruption "spewed out a lot of ash that completely blanketed the landscape."
On the site, scientists found thousands of bones from animals such as giraffes, elephants and wildebeests, swift runners in the antelope family. The hominins may have killed the animals for their meat or scavenged leftover meat. Competing carnivores included lions, leopards and hyenas, which also posed a threat to hominin safety, according to Ashley.
Paleoanthropologists "have started to have some ideas about whether hominins were actively hunting animals for meat sources or whether they were perhaps scavenging leftover meat sources that had been killed by say a lion or a hyena," she said.
"The subject of eating meat is an important question defining current research on hominins," she said. "We know that the increase in the size of the brain, just the evolution of humans, is probably tied to more protein."
The hominins' food also may have included wetland ferns for protein and crustaceans, snails and slugs.
Scientists think the hominins likely used the site for a long time, perhaps tens or hundreds of years, Ashley said.
"We don't think they were living there," she said. "We think they were taking advantage of the freshwater source that was nearby."
Hand prints on Wadi Sura II rock shelter made thousands of years ago. Picture: Emmanuelle Honore
Sahara Desert handprint mystery solved: Wadi Sura II prints 'not human'
March 1, 2016
They are the ancient sketches which some believe belong to babies or small children.
But one anthropologist believes she may have solved the mystery behind the tiny handprints on a Saharan rock shelter, and it turns out they're not human at all.
And while they might bare an eerie resemblance to alien life, Emmanuelle Honore believes the explanation behind them is far more organic.
According to the archeologist from the McDonald Institute for Archaeologist Research in the UK and Centre national de la recherche scientifique in France, the prints were made by a reptile.
Yes, as in lizards.
When the site of Wadi Sura II was discovered in Egypt's Western Desert in 2002, experts were left gobsmacked by the thousands of sketches and prints adorning the prehistoric site.
Estimating they were made between 6000-8000 years ago, the cave which features images of animals, humans and headless creatures, soon became known as Cafe of the Beasts and is one of the greatest ancient rock sites in the Sahara.
But it was the tiny human-like “hands” which interested researchers the most, with at least 13 prints noted.
Dr Honore noticed the small prints when she first visited the site in 2006 and recognised they were much smaller than baby hands with very long fingers so questioned whether they were actually human at all.
She told news.com.au when she went back to the site a few years later she decided to test the hypothesis that they didn't belong to babies, children or even premature infants.
The anthropologist first analysed hands from her children and babies in her own family and realised the prints were even smaller than those of her relatives.
She then brought together a team of experts to analyse the hand size of premature infants and found they didn't fit either so looked at the possibility of them belonging to primates.
The results of the study, which found the hands were unlikely to be human, have been published the Journal of Archeological Science.
"I had to admit that the proportions and measurements of non-human primates were not matching 100 per cent with the tiny hand stencils," she said.
"After many discussions with my colleagues of the Museum National d'Histoire Naturelle in Paris, especially Professor Brigitte Senut, a great primatologist and palaeoanthropologist, we decided to investigate the reptile hypothesis."
She said after consultation with several zoos and reptile experts her research showed the proportions were more closely aligned to the legs of desert monitor lizards, or the feet of young crocodiles.
"We are not sure if we will get a definitive answer, but our first results are also very convincing," she said of the latest research.
She said regardless of what the stencils were made by, the site still generated a lot of interest and the ongoing research was exciting.
"Wadi Sura II can be considered as the most important rock art site in all North Africa, because of the huge number of paintings," she said.
"The shelter is located in a very remote area and was only discovered recently."
Dr Honore said there has not been a lot of attempts to read and interpret the rock art, which she guessed dated back 6000 years, and researchers were still deciphering traces of prehistoric societies from which we know very little so far.
She said animal sketches were more common in Australia and South America but rare in the Sahara.
Plant biomarkers hint at early human habitat
February 22, 2016
Plant molecular fossils reveal details of an early human habitat at Olduvai Gorge, including the critical freshwater and plant resources available to early humans, according to a study conducted by an international team led by Clayton Magill of the Geological Institute in Zurich, Switzerland. Fossil evidence showing how early humans coexisted with critical plant and water resources is scant. As a result, how such local resources affected early human evolution remains unclear. To study the meter-scale spatial distribution of these resources, Magill and colleagues excavated 71 buried soil samples across a 25,000-square-meter area at a nearly 2-million-year-old Olduvai Gorge archaeological site. Different types of plants each have their own characteristic chemical biomarkers preserved in the soil. The authors analyzed these biomarkers to distinguish between co-occurring plant types. The biomarker evidence indicated a varied landscape containing different types of vegetation, including the presence of a woodland thicket near a small freshwater wetland, all surrounded by an open grassland landscape. This finding suggests that early humans living at Olduvai Gorge had reliable and easy access to potable water, edible plants, and aquatic animals. The thicketed area delineated by biomarkers also contained butchered animal bones and early human remains. According to the authors, early humans may have brought animal remains and food from the surrounding grasslands or wetlands to the wooded habitat, which may have provided protection and access to freshwater.
Neanderthals mated with modern humans much earlier than previously thought, study finds
February 17, 2016
Using several different methods of DNA analysis, an international research team has found what they consider to be strong evidence of an interbreeding event between Neanderthals and modern humans that occurred tens of thousands of years earlier than any other such event previously documented.
Today in Nature the team publishes evidence of interbreeding that occurred an estimated 100,000 years ago. More specifically the scientists provide the first genetic evidence of a scenario in which early modern humans left the African continent and mixed with archaic (now-extinct) members of the human family prior to the migration "out of Africa" of the ancestors of present-day non-Africans, less than 65,000 years ago.
"It's been known for several years, following the first sequencing of the Neanderthal genome in 2010, that Neanderthals and humans must have interbred," says Professor Adam Siepel, a co-team leader and Cold Spring Harbor Laboratory (CSHL) quantitative biologist. "But the data so far refers to an event dating to around 47,000-65,000 years ago, around the time that human populations emigrated from Africa. The event we found appears considerably older than that event."
In addition to Siepel, who is Chair of CSHL's Simons Center for Quantitative Biology, the team included several members of the Max Plank Institute for Evolutionary Anthropology, including Martin Kuhlwilm, Svante Pääbo, Matthias Meyer and co-team leader Sergi Castellano. Kuhlwilm was co-first author of the new paper with Ilan Gronau, a former member of Siepel's Lab who is now at the Herzliya Interdisciplinary Center, Israel. Melissa Hubisz, a Ph.D. student with Siepel at Cornell University, also made major contributions to the work. The full international research team included 15 additional co-authors.
"One very interesting thing about our finding is that it shows a signal of breeding in the 'opposite' direction from that already known," Siepel notes. "That is, we show human DNA in a Neanderthal genome, rather than Neanderthal DNA in human genomes."
This finding, the result of several kinds of advanced computer modeling algorithms comparing complete genomes of hundreds of contemporary humans with complete and partial genomes of four archaic humans, has implications for our knowledge of human migration patterns.
People living today who are of European, Eurasian and Asian descent have well-identified Neanderthal-derived segments in their genome. These fragments are traces of interbreeding that followed the "out of Africa" human migration dating to about 60,000 years ago. They imply that children born of Neanderthal-modern human pairings outside of Africa were raised among the modern humans and ultimately bred with other humans, explaining how bits of Neanderthal DNA remain in human genomes.
Contemporary Africans, however, do not have detectable traces of Neanderthal DNA in their genomes. This indicates that whatever sexual contact occurred between modern humans and Neanderthals occurred among humans who left the African continent. "Ancestors of present-day African populations likely didn't have the opportunity to interbreed with Neanderthals, who lived largely outside of Africa," explains co-author Ilan Gronau.
The team's evidence of "gene flow" from descendants of modern humans into the Neanderthal genome applies to one specific Neanderthal, whose remains were found some years ago in a cave in southwestern Siberia, in the Altai Mountains, near the Russia-Mongolia border. The modern human ancestor who contributed genes to this particular Neanderthal individual - called the "Altai Neanderthal," and known from a tiny toe bone fragment - must have migrated out of Africa long before the migration that led Africans into Europe and Asia 60,000 years ago, the scientists say.
In contrast, the two Neanderthals from European caves that were sequenced for this study -- one from Croatia, another from Spain -- both lack DNA derived from ancestors of modern humans. The team also included in their analysis DNA from another archaic human relative, a Denisovan individual, whose remains were found in the same cave in the Altai Mountains. Denisovans, like Neanderthals, are members of the human line that eventually became extinct. Both of these archaic human cousins lived in the same cave, although at different times in the past.
The Denisovan analyzed in this study did not have traces of modern human DNA, unlike the Neanderthal found in the same cave. That doesn't mean modern human ancestors never mated with Denisovans or European Neanderthals.
What it does mean, Siepel clarifies, is that "the signal we're seeing in the Altai Neanderthal probably comes from an interbreeding event that occurred after this Neanderthal lineage diverged from its archaic cousins, a little more than 100,000 years ago."
The modern human sequences in the Altai Neandertal appear to derive from a group of modern human ancestors from Africa that separated early from other humans, about the time present-day African populations diverged from one another, around 200,000 years ago. Thus, there must have been a long lag between the time when this group branched off the modern human family tree, roughly 200,000 years ago, and the time they left their genetic mark in the Altai Neandertal, about 100,000 years ago, before being lost to extinction themselves.
The team's analysis included more than 500 genomes of contemporary Africans. "I was looking to see if I could find genomic regions where the Altai Neanderthal has sequences resembling those we see in humans," says Martin Kuhlwilm. "We know that contemporary non-Africans have traces of Neanderthal in them, so they were not useful in this search. Instead, we used the genomes of contemporary individuals from five populations across Africa to identify mutations which most of them have in common."
This was the data that provided evidence of "regions in the Altai Neanderthal genome that carry mutations observed in the Africans - but not in the Denisovan" or in Neanderthals found in European caves.
"This is consistent with the scenario of gene flow from a population closely related to modern humans into the Altai Neanderthal. After ruling out contamination of DNA samples and other possible sources of error, we are not able to explain these observations in any other way," Siepel says.
Sterkfontein Caves produce two new hominin fossils
February 11, 2016
Two new hominin fossils have been found in a previously uninvestigated chamber in the Sterkfontein Caves, just North West of Johannesburg in South Africa.
The two new specimens, a finger bone and a molar, are part of a set of four specimens, which seem to be from early hominins that can be associated with early stone tool-bearing sediments that entered the cave more than two million years ago. During a second phase of excavation in the Milner Hall - a component of the Sterkfontein Caves - which was started early in 2015 with student Kelita Shadrach, four hominin fossils were excavated from the upper layers of a long sequence of deposits that document the long history of fossil deposition in the caves, starting over 3.67 million years ago.
"The [two] specimens are exciting not only because they are associated with early stone tools, but also because they possess a mixture of intriguing features that raise many more questions than they give answers," says lead researcher Dr Dominic Stratford, a lecturer at the Wits School of Geography, Archaeology and Environmental studies, and research coordinator at the Sterkfontein Caves.
The first fossil specimen, which is a very large proximal finger bone, is significantly larger and more robust than any other hand bone of any hominin yet found in South African plio-pleistocene sites.
"It is almost complete and shows a really interesting mix of modern and archaic features. For example, the specimen is markedly curved – more curved than Homo naledi and is similarly curved to the much older species Australopithecus afarensis," says Stratford.
The level of curvature is often linked to arborealism, but it lacks the strong muscle attachments that are expected to be present.
"The finger is similar in shape to the partial specimen from Olduvai Gorge that has been called Homo habilis, but is much larger. Overall, this specimen is unique in the South African plio-pleistocene fossil hominin record and deserves more studies," says Stratford.
The other fossil is a relatively small, nearly complete adult 1st molar tooth that also has striking similarities to species Homo habilis.
"In size and shape it also bears a resemblance to two of the 10 1st molars of the H.naledi specimens, although further and more detailed comparisons are needed to verify this."
The shape of the tooth and particularly the shape and relative sizes of the cones on the surface of the tooth suggest this specimen belonged to an early member of the Homo genus and can be associated with early stone tools dated recently to 2.18 million years ago.
"The two other hominin fossils found are still being studied and further excavations are planned to hopefully find more pieces and expand our understanding of who these intriguing bones belonged to and how they lived and died on the Sterkfontein hill more than two million years ago," says Stratford.
The Sterkfontein Legacy
The Sterkfontein Caves have been one of the most prolific palaeoanthropological sites in the world, since the discovery of the first ever adult Australopithecus by Robert Broom, 80 years ago this year. Since this incredible discovery, some of palaeoanthropology's most famous finds have come from the Sterkfontein Caves, including Ms. Ples and Little Foot.
Sterkfontein remains the richest Australopithecus-bearing locality in the world and continues to yield remarkable specimens. The underground network of caves at the site extends over 5kms and the caves are filled with fossiliferous sediments that have been deposited underground over a period of more than 3.67 million years.
However, very few of these deep deposits have been systematically excavated and so remain largely unknown. The Milner Hall, where the four new hominin fossils were found, is one such chamber where several large deposits have been identified but never excavated.
The excavations that yielded these new hominin fossils were being conducted as part of a series of exploratory excavations away from the known hominin-bearing areas. Excavations in the Jacovec Cavern, Name Chamber and Milner Hall have been started under Dr Stratford's direction. Each has yielded exciting new fossils that shed further light on the story of our evolution and life on the Sterkfontein hill more than two million years ago.
Study shows Australopithecus sediba didn't likely consume hard foods
A surprising find about a possible early human ancestor
February 8, 2016
Research published in 2012 garnered international attention by suggesting that Australopithecus sediba (A. sediba), a possible early human ancestor species discovered in South Africa by anthropologist Lee Berger, had lived on a diverse woodland diet including hard foods mixed in with tree bark, fruit, leaves and other plant products.
But new research by an international team of researchers now shows that A. sediba didn't have the jaw and tooth structure necessary to exist on a steady diet of hard foods.
"Most australopiths had amazing adaptations in their jaws, teeth and faces that allowed them to process foods that were difficult to chew or crack open. Among other things, they were able to efficiently bite down on foods with very high forces," said team leader David Strait, PhD, professor of anthropology in Arts & Sciences at Washington University in St. Louis.
"Australopithecus sediba is thought by some researchers to lie near the ancestry of Homo, the group to which our species belongs," said Justin Ledogar, PhD, Strait's former graduate student and now a researcher at the University of New England in Australia. "Now we find that A. sediba had an important limitation on its ability to bite powerfully; if it had bitten as hard as possible on its molar teeth using the full force of its chewing muscles, it would have dislocated its jaw."
The study, published Feb. 8 in the journal Nature Communications, describes biomechanical testing of a computer-based model of an A. sediba skull. The model is based on the fossil skull recovered in 2008 from the Malapa fossil site by Berger and his team. Malapa is a cave near Johannesburg, South Africa. The biomechanical methods used in the study are similar to those used by engineers to test whether or not planes, cars, machine parts or other mechanical devices are strong enough to avoid breaking during use.
A. sediba, a diminutive pre-human species that lived about two million years ago in southern Africa, has been heralded as a possible ancestor or close relative of Homo. Australopiths appear in the fossil record about four million years ago, and although they have some human traits like the ability to walk upright on two legs, most of them lack other characteristically human features like a large brain, flat faces with small jaws and teeth, and advanced tool-use.
Humans in the genus Homo are almost certainly descended from an australopith ancestor, and A. sediba is a candidate to be either that ancestor or something similar to it.
Some of the researchers who described A. sediba are also authors on the biomechanical study, including Lee Berger, PhD, and Kristian Carlson, PhD, of the University of the Witwatersrand, and Darryl de Ruiter, PhD, of Texas A&M University. Amanda Smith, PhD, a postdoctoral fellow in physical anthropology at Washington University, also participated in the research.
The new study does not directly address whether Australopithecus sediba is indeed a close evolutionary relative of early Homo, but it does provide further evidence that dietary changes were shaping the evolutionary paths of early humans.
"Humans also have this limitation on biting forcefully and we suspect that early Homo had it as well, yet the other australopiths that we have examined are not nearly as limited in this regard," Ledogar said. "This means that whereas some australopith populations were evolving adaptations to maximize their ability to bite powerfully, others (including A. sediba) were evolving in the opposite direction."
"Some of these ultimately gave rise to Homo," Strait said. "Thus, a key to understanding the origin of our genus is to realize that ecological factors must have disrupted the feeding behaviors and diets of australopiths. Diet is likely to have played a key role in the origin of Homo."
Strait, a paleoanthropologist who has written about the ecological adaptations and evolutionary relationships of early humans, as well as the origin and evolution of bipedalism, said this study offers a good example of how the tools of engineering can be used to answer evolutionary questions. In this case, they help us to better understand what the facial skeleton can tell us about the diet and lifestyles of humans and other primates.
"Our study provides a really nice demonstration of the difference between reconstructing the behaviors of extinct animals and understanding their adaptations." Strait said. "Examination of the microscopic damage on the surfaces of the teeth of A. sediba has led to the conclusion that the two individuals known from this species must have eaten hard foods shortly before they died. This gives us information about their feeding behavior. Yet, an ability to bite powerfully is needed in order to eat hard foods like nuts or seeds. This tells us that even though A. sediba may have been able to eat some hard foods, it is very unlikely to have been adapted to eat hard foods."
The bottom line, Strait said, is that the consumption of hard foods is very unlikely to have led natural selection to favor the evolution of a feeding system that was limited in its ability to bite powerfully. This means that the foods that were important to the survival of A. sediba probably could have been eaten relatively easily without high forces.
Egyptian archaeologists call for tougher security measures after 'sale of pyramid pieces'
February 7, 2016
In a video that went viral online, four people were shown breaking off and selling pieces of one of the Giza pyramid blocks, leaving archaeologists and antiquities lovers up in arms.
Privately owned Egyptian news site Dot Masr decided to investigate media reports that "pieces of the pyramid were being sold", resulting in the video of the sale, the website said.
The editors of the website were able to "buy a piece of the pyramids for EGP 300" following an agreement with one of the men, who is now in police custody, to buy chunks of the pyramid in order to send to a friend abroad.
The video sparked outrage on social media, with many users calling on the antiquities and tourism ministries to "save the pyramids."
Hussein Bassir, director of Giza Plateau, told Ahram Online that the incident happened in a remote area south of the Menkawre Pyramid, which is off the tourist track. Tourists normally visit areas around the Great Pyramid of Khufu, the Khafre Pyramid and the Sphinx.
Security personnel, Bassir continued, are always available around the plateau, but could not be expected to be everywhere, as the plateau is vast and difficult to control.
"The blocks shown in the video are authentic, but have fallen from the pyramid complex across the span of time and have not been broken off by thieves," he said.
"The criminals seen in the video were arrested and detained for four days on charges of vandalism, trading in antiquities, and fraud.
"The journalists shown in the video may also face charges of owning and trading in stolen antiquities," Bassir added, saying that their good intentions in reporting the incident is not sufficient to annul charges against them.
"The pieces of the pyramids are still in their possession. If they had handed over the blocks to the police immediately after receiving them, their situation may have been different."
He went on saying that the immediate response of the tourism and antiquities police was a "major element in catching the criminals rapidly".
Salah Al-Hadi, coordinator of the Archaeologists' Syndicate, argues that security has to be tightened in all archaeological sites, especially in open air sites such as the Giza Plateau and Saqqara Necropolis.
He said that the mission of an archaeologist is on site, and not inside the ministry's offices.
"The ministry should put into effect judicial decisions, to stop encroachment on monuments. Penalties under the antiquities law have to be stiffened," Al-Hadi asserted.
Archaeologist Mohamed Fawzi believes that poor security measures are behind what happened, as well as the encroachment on several archaeological sites.
"The low salaries of ministry employees led some of them to become careless in their work," he said.
New research sharpens understanding of poison-arrow hunting in Africa
February 1, 2016
While academic awareness of African peoples' hunting with poison-tipped arrows extends back for centuries, knowledge of the ingenious practice has been scattered among chemistry, entomology and anthropology texts.
Now, a comprehensive study of the hunting tradition of the San peoples of Namibia sheds new light on their use of beetle and plant poisons to boost the lethality of their arrows. The research appears currently in the peer-reviewed journal ZooKeys.
"The more slender threads of information I wove together from reports dating to the 1700s, the more obvious it became there were few sure facts and many hard-to-believe assertions," said lead author Caroline Chaboo, assistant professor of ecology and evolutionary biology at the University of Kansas. "The San are traditional hunter-gatherers and thus have a special place in the history of man. As I learned more about the modern San, their history, weak political status and endangered languages and cultures, it became urgent to me to document this aspect of their culture."
Chaboo and her co-authors - Megan Biesele of the Kalahari Peoples Fund, Robert K. Hitchcock of the University of New Mexico and Andrea Weeks of George Mason University - synthesized historical and anthropological literature and conducted their own fieldwork to better grasp how the San use beetle arrow poisons.
"The fieldwork was an unforgettable experience," Chaboo said. "Taking all our water and food into the Kalahari, where water was too precious to use for baths. Sleeping in a pop-up tent atop the Range Rover and waking in the middle of the night with hyenas sniffing around the campsite; or sleeping on the ground and feeling the roar of a lion through the ground. Seeing the first amazing rains flooding the Okavango Delta. Being welcomed into the San communities, and having the entire community sit around me and the arrow preparers, and hearing San spoken."
The investigation reports poison use for nine San nations in Botswana and Namibia: G|ui, G||ana, G||olo, Hai||on, Ju'|hoansi, Kua, Naro, Tsila and Xao-'aen.
"Arrow-hunting appears in ancient rock-paintings of the San, but it is unclear when poisons might have been adopted," Chaboo said. "We suspect poisons were adopted very early."
She said the San use arrows to hunt large game like antelope, buffalo, cheetah, eland, elephant, gazelle, giraffe, impala, lion, puku, springbok, warthog, wildebeest and zebra.
As an entomologist specializing in leaf-beetle species, Chaboo was especially interested how the San collect beetle poison, prepare it and apply it to arrows.
"In general, the beetle larvae are harvested by digging up soil around the host, sifting out the cocoons to take home," she said. "Later, the cocoons are cracked open and the beetle larvae extracted. Some San hunters squeeze the beetle body fluids out onto the arrowhead, or they make a concoction with other plant juices. The arrow preparer is very careful in handling all the materials and in storing the poisoned arrows and remaining cocoons away from the community."
According to the KU researcher, the biological purpose of the poison in beetles and plants remains unclear.
"This is the next big glaring question to answer," Chaboo said. "We can guess that this protein toxin has some physiological value to the insect, perhaps protecting it from the harsh dry climate above ground or possibly even an anti-predatory defense. These beetle larvae already have two other levels of defenses — their hard cocoons and their underground location."
Chaboo said the poison slowly brings about paralysis in the prey of San hunters, although the biological mechanism remains unclear.
"The poison is a slow-acting paralyzing poison," she said. "The animal continues to run after being hit, but over the next few hours, the animal becomes increasingly unable to move well, and it finally falls over. Then the hunter can finish off the animal. Cell breakdown and interference with cell membrane channels are implicated."
Indeed, this slow chase by the hunter is the basis for the San's famous tracking culture.
According to Chaboo, previous investigations by anthropologists have tended to work deeply with one or a few San communities. Chemists also made sporadic stabs at examining the San poisons, "but in the absence of entomologists, the identity of the poison sources has been ambiguous."
"I became convinced that the biological systematic approach offered the most superior and swiftest route to sorting out the story," said the KU researcher. "Systematics readily integrates data from other fields so our paper provides a comprehensive account of the anthropology, history, chemistry and taxonomy about arrow-poison beetles. It identifies some urgent questions to frame the next research steps."
Chaboo asserted that indigenous knowledge and practice, such as San hunting traditions, promise new understanding to scientists across many disciplines.
"It's remarkable that there is so much we still don't know about life on Earth and even about the intricate relationships humans have with the environment," she said. "Indigenous knowledge - accumulated over long periods of observations and experiences - holds deep insight about nature. Such knowledge can improve the quality of science and other fields and may offer resolutions to some pressing problems. For example, the San can teach us how to live better in a hotter world with diminishing drinking water."
Chaboo's work in Namibia was supported by the American Museum of Natural History and would also not have been possible with in-country collaboration with San communities and the National Museum of Namibia.
The interior of Cueva Victoria. Nano Sanchez, Wikimedia Commons
Latest study suggests early human dispersal into Spain through Strait of Gibraltar
January 2, 2016
Most recent dating places one wave of human dispersal out of Africa into southeastern Spain at almost one million years ago.
Using state-of-the-art dating methodologies, a team of scientists have obtained or confirmed a date range between .9 and .85 Mya (million years ago) as a time when a species of Old World monkey (Theropithecus) and an early species of human occupied the cave site of Cueva Victoria in southeastern Spain. It is a location not far from where many scientists have hypothesized that humans may have crossed over into Europe from North Africa through the Strait of Gibraltar at a time when seal levels were low enough to provide a land bridge between the two continents.
Using paleomagnetism, uranium-thorium, and vertebrate biostratigraphy dating techniques, Luis Gibert of the University of Barcelona, Spain, and colleagues from several other institutions conducted testing on fossiliferous breccia samples and other deposit samples from the cave. Their results showed that the fossil evidence for the Theropithecus presence was constrained to a range between .9 and .85 Mya. Similar dates have been obtained through previous studies on the Cueva Negra cave in the same region of Spain, which contained evidence of early human (Homo) fossils associated with what is arguably considered to be the earliest Acheulean-type stone tools in Europe.
The authors of the study suggest that the presence of the same species of Theropithecus, including Homo, at about the same time in North Africa, coupled with the absence of Theropithecus fossils elsewhere in Europe, supports the hypothesis of a dispersal of the two primates (Theropithecus and Homo) through the Strait of Gibraltar almost 1 million years ago. During this time, sea levels were low enough to create a land bridge at the Strait between Africa and Europe.
Previous studies by other teams have also suggested another, earlier human dispersal into southeastern Spain through the Strait of Gibraltar at about 1.3 million years ago, and the famous research and Homo fossil discoveries at Dmanisi in Georgia have suggested an even earlier Homo dispersal out of Africa, possibly through the Levant and up through Anatolia to the southern Caucasus at around 1.8 million years ago.
The study is published in press in the Journal of Human Evolution.