Monday, December 30, 2013
A team of Israeli scientists have reported the discovery of a hominin (early human) occupation site near Nesher Ramla, Israel. The site, according to archaeologist Yossi Zaidner of the Zinman Institute of Archaeology at the University of Haifa and colleagues, presents evidence for human occupation or use during Middle Paleolithic times (about 300,000 to 40 - 50,000 years ago).
Unearthed were numerous finds that comprised an 8-meter deep sequence of "rich and well-preserved lithic [worked stone tool artifacts] and faunal assemblages [animal and early human bones], combustion features [features evidencing use or presence of fire], hundreds of manuports [natural objects moved from their original locations possibly by human agency] and ochre."* Ochre, an iron oxide pigment, was often used for a variety of purposes by prehistoric humans, including the creation of wall paintings.
Thursday, December 19, 2013
The most complete sequence to date of the Neanderthal genome, using DNA extracted from a woman's toe bone that dates back 50,000 years, reveals a long history of interbreeding among at least four different types of early humans living in Europe and Asia at that time, according to University of California, Berkeley, scientists.
Population geneticist Montgomery Slatkin, graduate student Fernando Racimo and post-doctoral student Flora Jay were part of an international team of anthropologists and geneticists who generated a high-quality sequence of the Neanderthal genome and compared it with the genomes of modern humans and a recently recognized group of early humans called Denisovans.
Family tree of the four groups of early humans living in Eurasia 50,000 years ago and the lingering genetic heritage due to interbreeding. (Credit: Image courtesy of University of California - Berkeley)
The comparison shows that Neanderthals and Denisovans are very closely related, and that their common ancestor split off from the ancestors of modern humans about 400,000 years ago. Neanderthals and Denisovans split about 300,000 years ago.
Though Denisovans and Neanderthals eventually died out, they left behind bits of their genetic heritage because they occasionally interbred with modern humans. The research team estimates that between 1.5 and 2.1 percent of the genomes of modern non-Africans can be traced to Neanthertals.
Denisovans also left genetic traces in modern humans, though only in some Oceanic and Asian populations. The genomes of Australian aborigines, New Guineans and some Pacific Islanders are about 6 percent Denisovan genes, according to earlier studies. The new analysis finds that the genomes of Han Chinese and other mainland Asian populations, as well as of native Americans, contain about 0.2 percent Denisovan genes.
The genome comparisons also show that Denisovans interbred with a mysterious fourth group of early humans also living in Eurasia at the time. That group had split from the others more than a million years ago, and may have been the group of human ancestors known as Homo erectus, which fossils show was living in Europe and Asia a million or more years ago.
"The paper really shows that the history of humans and hominins during this period was very complicated," said Slatkin, a UC Berkeley professor of integrative biology. "There was lot of interbreeding that we know about and probably other interbreeding we haven't yet discovered."
The genome analysis will be published in the Dec. 19 issue of the journal Nature. Slatkin, Racimo and Jay are members of a large team led by former UC Berkeley post-doc Svante Pääbo, who is now at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
In another analysis, Jay discovered that the Neanderthal woman whose toe bone provided the DNA was highly inbred. The woman's genome indicates that she was the daughter of a very closely related mother and father who either were half-siblings who shared the same mother, an uncle and niece or aunt and nephew, a grandparent and grandchild, or double first-cousins (the offspring of two siblings who married siblings).
Further analyses suggest that the population sizes of Neanderthals and Denisovans were small and that inbreeding may have been more common in Neanderthal groups than in modern populations.
As part of the new study, Racimo was able to identify at least 87 specific genes in modern humans that are significantly different from related genes in Neanderthals and Denisovans, and that may hold clues to the behavioral differences distinguishing us from early human populations that died out.
"There is no gene we can point to and say, 'This accounts for language or some other unique feature of modern humans,'" Slatkin said. "But from this list of genes, we will learn something about the changes that occurred on the human lineage, though those changes will probably be very subtle."
According to Pääbo, the list of genes "is a catalog of genetic features that sets all modern humans apart from all other organisms, living or extinct. I believe that in it hide some of the things that made the enormous expansion of human populations and human culture and technology in the last 100,000 years possible."
The Pääbo group last year produced a high-quality Denisovan genome based on DNA from a pinky finger bone discovered in 2008 in Denisova Cave in the Altai Mountains of Southern Siberia. That bone is from a young woman who lived about 40,000 years ago. The Neanderthal toe bone was found in the same cave in 2010, though in a deeper layer of sediment that is thought to be about 10,000-20,000 years older. The cave also contains modern human artifacts, meaning that at least three groups of early humans occupied the cave at different times. The Pääbo group developed new techniques to extract DNA from these old bones.
Slatkin noted that no one is sure how long the various now-extinct groups lasted, but that there is evidence that Neanderthals and modern humans coexisted in Europe and Asia for at least 30,000 years. Interbreeding was infrequent, though how infrequent is unclear given the genomic information available today.
"We don't know if interbreeding took place once, where a group of Neanderthals got mixed in with modern humans, and it didn't happen again, or whether groups lived side by side, and there was interbreeding over a prolonged period," he said.
Monday, December 16, 2013
Neanderthals buried their dead, an international team of archaeologists has concluded after a 13-year study of remains discovered in southwestern France.
Their findings, which appear in the journal Proceedings of the National Academy of Sciences, confirm that burials took place in western Europe prior to the arrival of modern humans.
"This discovery not only confirms the existence of Neanderthal burials in Western Europe, but also reveals a relatively sophisticated cognitive capacity to produce them," explains William Rendu, the study's lead author and a researcher at the Center for International Research in the Humanities and Social Sciences (CIRHUS) in New York City.
CIRHUS is a collaborative arrangement between France's National Center for Scientific Research (CNRS) and New York University.
The findings center on Neanderthal remains first discovered in 1908 at La Chapelle-aux-Saints in southwestern France. The well-preserved bones led its early 20th-century excavators to posit that the site marked a burial ground created by a predecessor to early modern humans. However, their conclusions have sparked controversy in the scientific community ever since, with skeptics maintaining that the discovery had been misinterpreted and that the burial may not have been intentional.
Beginning in 1999, Rendu and his collaborators, including researchers from the PACEA laboratory of the University of Bordeaux and Archéosphère, a private research firm, began excavating seven other caves in the area.
In this excavation, which concluded in 2012, the scientists found more Neanderthal remains—two children and one adult—along with bones of bison and reindeer.
While they did not find tool marks or other evidence of digging where the initial skeleton was unearthed in 1908, geological analysis of the depression in which the remains were found suggests that it was not a natural feature of the cave floor.
As part of their analysis, the study's authors also re-examined the human remains found in 1908. In contrast to the reindeer and bison remains at the site, the Neanderthal remains contained few cracks, no weathering-related smoothing, and no signs of disturbance by animals.
"The relatively pristine nature of these 50,000-year-old remains implies that they were covered soon after death, strongly supporting our conclusion that Neanderthals in this part of Europe took steps to bury their dead," observes Rendu. "While we cannot know if this practice was part of a ritual or merely pragmatic, the discovery reduces the behavioral distance between them and us."
Wednesday, December 11, 2013
Research led by the University of Southampton has found that early humans were driven by a need for nutrient-rich food to select 'special places' in northern Europe as their main habitat. Evidence of their activity at these sites comes in the form of hundreds of stone tools, including handaxes.
A study led by physical geographer at Southampton Professor Tony Brown, in collaboration with archaeologist Dr Laura Basell at Queen's University Belfast, has found that sites popular with our early human ancestors, were abundant in foods containing nutrients vital for a balanced diet. The most important sites, dating between 500,000 to 100,000 years ago were based at the lower end of river valleys, providing ideal bases for early hominins – early humans who lived before Homo sapiens (us).
Professor Brown says: "Our research suggests that floodplain zones closer to the mouth of a river provided the ideal place for hominin activity, rather than forested slopes, plateaus or estuaries. The landscape in these locations tended to be richer in the nutrients critical for maintaining population health and maximising reproductive success."
The project was funded by English Heritage and the University of Southampton's Faculty of Social and Human Sciences. It involved academics from Geography and Environment and Medicine at Southampton, together with Archaeology at Queen's.
The researchers began by identifying Palaeolithic sites in southern England and northern France where high concentrations of handaxes had been excavated –for example at Dunbridge in Hampshire, Swanscombe near Dartford and the Somme Valley in France. They found there were fewer than 25 sites where 500 handaxes or more were discovered. The high concentration of these artefacts suggests significant activity at the sites and that they were regularly used by early hominins.
Professor Brown and his colleagues then compiled a database of plants and animals known to exist in the Pleistocene epoch (a period between 2.6 million to 11,700 years ago) to establish a potential list of nutrient resources in the landscape and an estimation of the possible diet. This showed that an abundance of nutritious foods were available and suggests this was likely to have been the dominant factor driving early humans to focus on these sites in the lower reaches of river valleys, close to the upper tidal limit of rivers.
Over 50 nutrients are needed to sustain human life. In particular, it would have been essential for early humans to find sources of protein, fats, carbohydrates, folic acid and vitamin C. The researchers suggest vitamins and protein may have come from sources such as raw liver, eggs, fish and plants, including watercress (which grows year round). Fats in particular, may have come from bone marrow, beaver tails and highly nutritious eels.
The nutritional diversity of these sites allowed hominins to colonise the Atlantic fringe of north west Europe during warm periods of the Pleistocene. These sites permitted the repeated occupation of this marginal area from warmer climate zones further south
Professor Brown comments: "We can speculate that these types of locations were seen as 'healthy' or 'good' places to live which hominins revisited on a regular basis. If this is the case, the sites may have provided 'nodal points' or base camps along nutrient-rich route-ways through the Palaeolithic landscape, allowing early humans to explore northwards to more challenging environments."
Saturday, December 7, 2013
Dr. Doron Ben Ami of the the Israel Antiquities Authority shows the remains of a building dating to the Hasmonean Period which was discovered during excavations at the archaeological site of the biblical City of David, outside Jerusalem's old city walls on December 3, 2013. In recent months the remains of the impressive building from the Hasmonean period (second century BCE) are being unearthed in excavations directed by the Israel Antiquities Authority. AFP PHOTO/MENAHEM KAHANA.
In recent months remains of an impressive building from the Hasmonean period (second century BCE) are being unearthed in excavations the Israel Antiquities Authority is directing in the Giv‘ati parking lot, located in the City of David in the Walls Around Jerusalem National Park.
Photograph: Assaf Peretz, courtesy of the Israel Antiquities Authority
The building stands c. 4 meters high and covers an area of c. 64 sq. m. The building’s broad walls (more than one meter thick) are made of roughly hewn limestone blocks that were arranged as headers and stretchers, a construction method characteristic of the Hasmonean period. Although numerous pottery vessels were discovered inside the building, it was mainly the coins that surprised the researchers. These indicated the structure was erected in the early second century BCE and continued into the Hasmonean period, during which time significant changes were made inside it.
According to Dr. Doron Ben Ami and Yana Tchekhanovets, the excavation directors on behalf to the Israel Antiquities Authority, “The importance of this discovery is primarily because of the conspicuous paucity of buildings from the Hasmonean city of Jerusalem in archaeological research, despite the many excavations that have been conducted to date. Apart from several remains of the city’s fortifications that were discovered in different parts of Jerusalem, as well as pottery and other small finds, none of the Hasmonean city’s buildings have been uncovered so far, and this discovery bridges a certain gap in Jerusalem’s settlement sequence. The Hasmonean city, which is well-known to us from the historical descriptions that appear in the works of Josephus, has suddenly acquired tangible expression”.
Wednesday, December 4, 2013
Scientists have found that Neanderthals organized their living spaces in ways that would be familiar to modern humans, a discovery that once again shows similarities between these two close cousins.
The findings, published in the latest edition of the Canadian Journal of Archaeology, indicate that Neanderthals butchered animals, made tools and gathered round the fire in different parts of their shelters.
"There has been this idea that Neanderthals did not have an organized use of space, something that has always been attributed to humans," said Julien Riel-Salvatore, assistant professor of anthropology at the University of Colorado Denver and lead author of the study. "But we found that Neanderthals did not just throw their stuff everywhere but in fact were organized and purposeful when it came to domestic space."
The findings are based on excavations at Riparo Bombrini, a collapsed rock shelter in northwest Italy where both Neanderthals and, later, early humans lived for thousands of years. This study focused on the Neanderthal levels while future research will examine the more recent modern human levels at the site. The goal is to compare how the two groups organized their space.
The site comprises three levels assigned to Neanderthals. Scientists found that Neanderthals divided the cave into different areas for different activities. The top level was used as a task site – likely a hunting stand - where they could kill and prepare game. The middle level was a long-term base camp and the bottom level was a shorter term residential base camp.
Riel-Salvatore and his team found a high frequency of animal remains in the rear of the top level, indicating that the area was likely used for butchering game. They also found evidence of ochre use in the back of the shelter.
"We found some ochre throughout the sequence but we are not sure what it was used for," Riel-Salvatore said. "Neanderthals could have used it for tanning hides, for gluing, as an antiseptic or even for symbolic purposes – we really can't tell at this point."
In the middle level, which has the densest traces of human occupation, artifacts were distributed differently. Animal bones were concentrated at the front rather than the rear of the cave. This was also true of the stone tools, or lithics. A hearth was in back of the cave about half a meter to a meter from the wall. It would have allowed warmth from the fire to circulate among the living area.
"When you make stone tools there is a lot of debris that you don't want in high traffic areas or you risk injuring yourself," Riel-Salvatore said. "There are clearly fewer stone artifacts in the back of the shelter near the hearth."
The bottom level, thought to represent a short-term base camp, is the least well known because it was exposed only over a very small area. More stone artifacts were found immediately inside the shelter's mouth, suggesting tool production may have occurred inside the part of the site where sunlight was available. Some shellfish fragments also suggest that Neanderthals exploited the sea for food; like ochre, these are found in all the levels.
The discoveries are the latest in continuing research by Riel-Salvatore showing that Neanderthals were far more advanced than originally thought.
In an earlier study, he found that Neanderthals were highly innovative, creating bone tools, ornaments and projectile points. He also co-authored a paper demonstrating that interbreeding between Neanderthals and humans may have led to the ultimate demise of the outnumbered hominins. Still, Neanderthal genes make up between one and four percent of today's human genome, especially among Europeans.
"This is ongoing work, but the big picture in this study is that we have one more example that Neanderthals used some kind of logic for organizing their living sites," Riel-Salvatore said. "This is still more evidence that they were more sophisticated than many have given them credit for. If we are going to identify modern human behavior on the basis of organized spatial patterns, then you have to extend it to Neanderthals as well."