lunes, 29 de septiembre de 2008
More than 80 years after the discovery of the tomb of Tutankhamun, Egypt's Supreme Council of Antiquities has stunned the world of Egyptology by revealing that another tomb has been found, just four metres away from Tutankhamun in the Valley of the Kings.
For a long time it was thought that the valley, opposite the modern city of Luxor and the source of many of the most famous discoveries, had given up all of its secrets.
The discovery was the work of a team of American archaeologists from the University of Memphis led by Otto Schaden.
"It's very, very exciting," said Patricia Podvorzski, curator of Egyptian Art at the University of Memphis. "It was completely unexpected, so long after the discovery of Tutankhamun's tomb. Many archaeologists said the valley was done 100 years ago." Dr Schaden's find is the 63rd tomb to be opened in the valley.
The newly discovered 18th-dynasty tomb contains five mummies in intact sarcophagi with coloured funerary masks, along with more than 20 large storage jars sealed with pharaonic seals, according to Zahi Hawass, head of the Supreme Council of Antiquities.
The sarcophagi are carved in human form, like Tutankhamun's. The tomb is rectangular, and the wooden sarcophagi are surrounded by the jars, which seem to have been placed haphazardly, suggesting that the burial had been completed quickly, according to Dr Hawass.
Dr Schaden has been working in the valley on the Amenmesse Tomb Project, a minor tomb of the 19th dynasty, for many years. "They had finished clearing up that tomb and had started to dig down to the bedrock in front of the entrance," said Dr Podvorzski. "They were looking for foundation deposits - the models of tools, vessels and other things that were put around the tomb of a king to assure the permanence of the structure. While doing that they found workmen's huts made of dry stone and dating from the 19th dynasty. I believe they were in the process of dismantling the huts when they found the new tomb."
It was a very similar chain of events that led to the discovery of Tutankhamun's tomb in 1922. That, too, had been covered by ancient workmen's huts. "That was why the tombs didn't get robbed," added Dr Podvorzski. "The ancient Egyptian tomb robbers saw the huts and assumed there was nothing underneath them."
Although the discovery came as a huge surprise, there had been a suspicion that something else might be found. "Some time ago a British team did remote sensing around the tomb and said they thought there might be something down there," said Dr Podvorzski.
Details of the find are expected to be announced officially by Egypt's Supreme Council of Antiquities today, including possibly the identities of the occupants.
Kent Weeks, an American archaeologist, said the tomb was a single chamber, probably intended for a single mummy. Some or all of the other sarcophagi could have been put in later. He added that photographs of the tomb suggested it did not belong to a king. "It could be the tomb of a king's wife or son, or of a priest or court official," he said. "It clearly proves that the Valley of the Kings is still not exhausted. There are probably many more tombs to be found in it."
Whatever the new tomb may contain, its fate is certain: Egypt's policy on undisturbed tombs is clear. "This stuff will stay in Egypt," said Dr Podvorzski.
viernes, 26 de septiembre de 2008
A former Air Force pilot, Yves Rossy has spent much of his career flying thousands of people around the planet as a captain for SWISS. But when Rossy is not flying planes, he is jumping out of them. Freestyle, skysurf, freely – you name it, he has done it. But no matter how daring, these adventure sports never fulfilled his childhood dream: to soar like a bird. Not with a glider, but with a propelled fixed wing. Appearing live on National Geographic Channel in Jet Man Live, Rossy will attempt to become the first person to cross the English Channel using a single, jet-propelled wing.
Rossy devotes all of his spare time to flying in the purest sense, carrying out more and more tests using equipment developed on a trial and error basis: an inflatable wing, which carried him over the 12 kilometres separating the Swiss and French banks of Lake Geneva, a paraglider and a surf board that sent him skimming through Geneva’s water fountain before spectacularly grabbing the handle of a water skier, and a skydiving adventure on a disc “above” the Matterhorn. Today, Rossy has become FusionMan, the first man in the world to attach jet engines to a single wing and fly.
Growing up with his head in the clouds and his feet on the ground, Rossy pursued a technical apprenticeship and then graduated in engineering. As a fighter pilot, discovering the Mirage III supersonic fighter plane was certainly one of the high points of Rossy’s career. He flew the aircraft for 15 years, and also piloted historic aircraft such as the Hunter and the Venom.
An accomplished sportsman, his past and present hobbies include surfing, water-skiing, wakeboarding, skysurfing, parachuting, aerobatics, motorbike riding, rafting and hang-gliding, to name but a few. Flying under a jet wing is the culmination of a 30-year career interspersed with exploits and firsts.
Yves Rossy was born on 27, August 1959, in Neuchatel, Switzerland. He speaks English, French and German fluently.
jueves, 25 de septiembre de 2008
Neanderthals living in a pair of caves on the Mediterranean Sea regularly feasted on mussels, fish, and other types of marine life, according to a new study.
The finding suggests that Neanderthals actively foraged for seafood just like early modern humans, according to Clive Finlayson, an anthropologist at the Gibraltar Museum.
Neanderthals and modern humans are distinct species that split from a common ancestor several hundred thousand years ago.
Why modern humans thrived and Neanderthals ultimately failed has long been a topic of scientific intrigue, and previous research had suggested that the ability to exploit marine resources was one of the defining characteristics for the success of modern humans.
But the new research may eliminate sophisticated foraging skills from the list of potential advantages unique to humans.
"I don't think that the success of one or the other had to do with subsistence, with the way they hunted or fed," Finlayson said.
"There may be other factors coming into this, or it may just have been a question of luck."
The new theory is based on excavations of two caves on the western edge of Gibraltar, a British territory at the southern tip of Spain (see map).
Previous studies showed Neanderthals periodically occupied the caves as recently as 28,000 years ago.
Inside the caves Finlayson and his colleagues found mussel shells and the bones of seals, dolphins, and fish mixed in with the remains of deer and other land mammals.
Many of the bones show signs of being cooked over a fire, and some have marks left by stone tools used to cleave off chunks of flesh.
Seafood remains are found throughout various layers in the caves, indicating that Neanderthals regularly exploited marine resources for tens of thousands of years.
"It seems to suggest that this wasn't a one-off, but that these guys were doing it on a regular basis," Finlayson said.
He and colleagues describe the findings online today in the journal Proceedings of the National Academy of Sciences.
Curtis Marean is an anthropologist at Arizona State University in Tempe who has found evidence that prehistoric humans were feasting on seafood in South Africa 165,000 years ago.
Marean said the new study clearly shows that Neanderthals occasionally ate seafood. But he is not convinced their exploitation of seafood was on par with that of early modern humans in Africa.
"I don't think there's enough evidence here to indicate that they are systematically being a coastal forager in the sense that we think of coastal foragers," he said.
In South Africa, Marean noted, scientists have found waste piles called shell middens that date back nearly a hundred thousand years. These piles contain several thousand pieces of shellfish discarded by humans.
By contrast, the Gibraltar caves yielded just 149 pieces of shellfish. Those pieces could be from a handful of mussels, Marean noted.
The differences in abundance could stem from different availabilities of seafood at the two sites, or in the abilities of the two species to actively forage for ocean food, he added.
To resolve the issue, Marean recommends a systematic comparison of Neanderthal and human seafood collection at sites with similar availability.
"Were Neanderthals [exploiting seafood] like we expect they would if they were modern? And if they weren't, then the question is: Why?" he said.
"We could be getting into something interesting there, for sure."
martes, 23 de septiembre de 2008
September 22, 2008
Full-power operation of the world's largest atom smasher will be delayed at least two months because of an electrical malfunction.
Twenty years in the making, the Large Hadron Collider (LHC) near Geneva, Switzerland, was designed to investigate dark matter, the big bang, and other mysteries of the early universe. (Interactive: understanding the God particle.)
Operators hurled the first beam of low-energy particles through the collider's 17-mile (27-kilometer) underground track just over a week ago.
The successful test had officials hopeful that they could start smashing opposing beams of particles together in as little as two week's time.
But during a routine test on September 19, an electrical link failed between two of the machine's massive 30-ton superconducting magnets, which guide speeding particles through the track.
"What we know indicates there was a faulty connection between two cables joining two magnets together that warmed up to the point of melting and that resulted in helium being leaked into the tunnel," said James Gillies, a spokesperson for the European Organization for Nuclear Research (CERN), which operates the machine.
No one was hurt during the malfunction, and the problem has been confined to a roughly two-mile (three-kilometer) swath of the track.
"This was actually the final electrical test of the final electrical circuit for qualification for running at high energy," Gillies told National Geographic News.
"This would have been the last hurdle."
Repairs are expected to take at least two months, thus squashing any hope that the LHC will be ready for its official inauguration, set for October 21.
The delay is due to the fact that the collider's operating temperature inside the track is -456.3 degrees Fahrenheit (-271.3 degrees Celsius).
For engineers to fix the problem, the section has to be warmed up, repaired, and cooled back down, a process known as a thermal cycle.
The thermal cycle for the LHC is about two months.
"The thing that went wrong [at the LHC] is not such a big deal," said Mike Harrison, a high-energy physicist at Brookhaven National Laboratories in Upton, New York.
"The actual fix will be a day or two probably," he said. "The problem is you have to warm it up and cool it down again. That's what takes up time."
Harrison added that this kind of delay is just part of the process of getting a particle accelerator ready for business.
He was involved in the design and fabrication of Brookhaven's Relativistic Heavy Ion Collider (RHIC), a smaller version of the LHC that's been in operation since 2000.
"You expect to have probably a couple of thermal cycles as you go through the commissioning process" of a particle accelerator, Harrison said.
CERN's Gillies agreed that "teething troubles" are inevitable with a machine as complicated as the LHC, and that other particle accelerators have faced similar problems.
"It's one of those things you have to be ready for when you start to operate a machine like this," he said.
"It's just more time-consuming with a superconducting machine, where you have a warm-up and a cool-down phase involved with any repair."
The LHC is also scheduled to be shut down in December to reduce electrical costs in the winter, and it is currently unclear whether repairs will be finished before then
September 19, 2008--The newly named maugean skate may go extinct before scientists have a chance to fully document it.
The skate--a type of ray--is among 113 new species of Australian sharks and rays discovered during a study of museum specimens, scientists at the Australian Commonwealth Scientific and Research Organization (CSIRO) announced this week. (Read full story.)
(See a giant freshwater ray caught near a Thai city.)
The 18-month-long project used modern DNA techniques on creatures that had previously been only casually named. Many still lack an official moniker.
A living relic, the maugean skate has roamed the waters near southwestern Tasmania--an Australian island state--for hundreds of millions of years.
Yet overfishing and a tiny habitat of just three estuaries has already given it endangered status on the International Union for the Conservation of Nature's Red List of Threatened Species.
viernes, 19 de septiembre de 2008
A tall, cheerful Swede, Pääbo is the main engine behind a breathtaking scientific tour de force: the attempt, expected to be completed next month, to read out not just single Neanderthal genes, but the entire three-billion-letter sequence of the Neanderthal genome. Traces of DNA in fossils are vanishingly faint, and because Neanderthal DNA is ever so close to that of living people, one of the biggest hurdles in sequencing it is the ever present threat of contamination by modern human DNA—especially by the scientists handling the specimens. The precautions taken in excavating at El Sidrón are now becoming standard practice at other Neanderthal sites. Most of the DNA for Pääbo's genome project, however, has come from the Croatian specimen, a 38,000-year-old fragment of leg bone found almost 30 years ago in the Vindija cave. Originally deemed unimportant, it sat in a drawer in Zagreb, largely untouched and thus uncontaminated, for most of its museum life.
Now it is the equivalent of a gold mine for prehistoric human DNA, albeit an extremely difficult mine to work. After the DNA is extracted in a sterile laboratory in the basement of the Max Planck Institute, it is shipped overnight to Branford, Connecticut, where collaborators at 454 Life Sciences have invented machines that can rapidly decipher the sequence of DNA's chemical letters. The vast majority of those letters spell out bacterial contaminants or other non-Neanderthal genetic information. But in the fall of 2006, Pääbo and his colleagues announced they had deciphered approximately one million letters of Neanderthal DNA. (At the same time, a second group, headed by Edward Rubin at the Department of Energy Joint Genome Institute in Walnut Creek, California, used DNA provided by Pääbo to read out snippets of genetic code using a different approach.) By last year, dogged by claims that their work had serious contamination problems, the Leipzig group claimed to have improved accuracy and identified about 70 million letters of DNA—roughly 2 percent of the total.
"We know that the human and chimpanzee sequences are 98.7 percent the same, and Neanderthals are much closer to us than chimps," said Ed Green, head of biomathematics in Pääbo's group in Leipzig, "so the reality is that for most of the sequence, there's no difference between Neanderthals and [modern] humans." But the differences—less than a half percent of the sequence—are enough to confirm that the two lineages had begun to diverge around 700,000 years ago. The Leipzig group also managed to extract mitochondrial DNA from two fossils of uncertain origin that had been excavated in Uzbekistan and southern Siberia; both had a uniquely Neanderthal genetic signature. While the Uzbekistan specimen, a young boy, had long been considered a Neanderthal, the Siberian specimen was a huge surprise, extending the known Neanderthal range some 1,200 miles east of their European stronghold.
So, while the new genetic evidence appears to confirm that Neanderthals were a separate species from us, it also suggests that they may have possessed human language and were successful over a far larger sweep of Eurasia than previously thought. Which brings us back to the same hauntingly persistent question that has shadowed them from the beginning: Why did they disappear?
To coax a Neanderthal fossil to reveal its secrets, you can measure it with calipers, probe it with a CT scan, or try to capture the ghost of its genetic code. Or if you happen to have at your disposal a type of particle accelerator called a synchrotron, you can put it in a lead-lined room and blast it with a 50,000-volt x-ray beam, without disturbing so much as a single molecule.
Over a sleep-deprived week in October 2007, a team of scientists gathered at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, for an unprecedented "convention of jawbones." The goal was to explore a crucial question in the life history of the Neanderthals: Did they reach maturity at an earlier age than their modern human counterparts? If so, it might have implications for their brain development, which in turn might help explain why they disappeared. The place to look for answers was deep inside the structure of Neanderthal teeth.
"When I was young, I thought that teeth were not so useful in assessing recent human evolution, but now I think they are the most important thing," said Jean-Jacques Hublin, who had accompanied his Max Planck Institute colleague Tanya Smith to Grenoble.
Along with Paul Tafforeau of the ESRF, Hublin and Smith were squeezed into a computer-filled hutch at the facility—one of the three largest synchrotrons in the world, with a storage ring for energized electrons half a mile in circumference—watching on a video monitor as the x-ray beam zipped through the right upper canine of an adolescent Neanderthal from the site of Le Moustier in southwestern France, creating arguably the most detailed dental x-ray in human history. Meanwhile, a dream team of other fossils sat on a shelf nearby, awaiting their turn in the synchrotron's spotlight: two jawbones of Neanderthal juveniles recovered in Krapina, Croatia, dating back 130,000 to 120,000 years; the so-called La Quina skull from a Neanderthal youth, discovered in France and dating from between 75,000 to 40,000 years ago; and two striking 90,000-year-old modern human specimens, teeth intact, found in a rock shelter called Qafzeh in Israel.
When teeth are imaged at high resolution, they reveal a complex, three-dimensional hatch of daily and longer periodic growth lines, like tree rings, along with stress lines that encode key moments in an individual's life history. The trauma of birth etches a sharp neonatal stress line on the enamel; the time of weaning and episodes of nutritional deprivation or other environmental stresses similarly leave distinct marks on developing teeth. "Teeth preserve a continuous, permanent record of growth, from before birth until they finish growing at the end of adolescence," Smith explained. Human beings take longer to reach puberty than chimpanzees, our nearest living relatives—which means more time spent learning and developing within the context of the social group. Early hominin species that lived on the savanna in Africa millions of years ago matured fast, more like chimps. So when in evolution did the longer modern pattern begin?
To address this question, Smith, Tafforeau, and colleagues had previously used the synchrotron to demonstrate that an early modern human child from a site called Jebel Irhoud in Morocco (dated to around 160,000 years ago) showed the modern human life history pattern. In contrast, the "growth rings" in the 100,000-year-old tooth of a young Neanderthal discovered in the Scladina cave in Belgium indicated that the child was eight years old when it died and appeared to be on track to reach puberty several years sooner than the average for modern humans. Another research team, using a single Neanderthal tooth, had found no such difference between its growth pattern and that of living humans. But while a full analysis from the "jawbone convention" would take time, preliminary results, Smith said, were "consistent with what we see in Scladina."
"This would certainly affect Neanderthal social organization, mating strategy, and parenting behavior," says Hublin. "Imagine a society where individuals start to reproduce four years earlier than in modern humans. It's a very different society. It could also mean the Neanderthals' cognitive abilities may have been different from modern humans'."
Neanderthal society may have differed in another way crucial to group survival: what archaeologists call cultural buffering. A buffer is something in a group's behavior—a technology, a form of social organization, a cultural tradition—that hedges its bets in the high-stakes game of natural selection. It's like having a small cache of extra chips at your elbow in a poker game, so you don't have to fold your hand quite as soon. For example, Mary Stiner and Steven Kuhn of the University of Arizona argue that early modern humans emerged from Africa with the buffer of an economically efficient approach to hunting and gathering that resulted in a more diverse diet. While men chased after large animals, women and children foraged for small game and plant foods. Stiner and Kuhn maintain that Neanderthals did not enjoy the benefits of such a marked division of labor. From southern Israel to northern Germany, the archaeological record shows that Neanderthals instead relied almost entirely on hunting big and medium-size mammals like horses, deer, bison, and wild cattle. No doubt they were eating some vegetable material and even shellfish near the Mediterranean, but the lack of milling stones or other evidence for processing plant foods suggests to Stiner and Kuhn that to a Neanderthal vegetables were supplementary foods, "more like salads, snacks, and desserts than energy-rich staple foods."
Their bodies' relentless demand for calories, especially in higher latitudes and during colder interludes, probably forced Neanderthal women and children to join in the hunt—a "rough and dangerous business," write Stiner and Kuhn, judging by the many healed fractures evident on Neanderthal upper limbs and skulls. The modern human bands that arrived on the landscape toward the end of the Neanderthals' time had other options.
"By diversifying diet and having personnel who [did different tasks], you have a formula for spreading risk, and that is ultimately good news for pregnant women and for kids," Stiner told me. "So if one thing falls through, there's something else." A Neanderthal woman would have been powerful and resilient. But without such cultural buffering, she and her young would have been at a disadvantage.
Of all possible cultural buffers, perhaps the most important was the cushion of society itself. According to Erik Trinkaus, a Neanderthal social unit would have been about the size of an extended family. But in early modern human sites in Europe, Trinkaus said, "we start getting sites that represent larger populations." Simply living in a larger group has biological as well as social repercussions. Larger groups inevitably demand more social interactions, which goads the brain into greater activity during childhood and adolescence, creates pressure to increase the sophistication of language, and indirectly increases the average life span of group members. Longevity, in turn, increases intergenerational transmission of knowledge and creates what Chris Stringer calls a "culture of innovation"—the passage of practical survival skills and toolmaking technology from one generation to the next, and later between one group and another.
Whatever the suite of cultural buffers, they may well have provided an extra, albeit thin, layer of insulation against the harsh climatic stresses that Stringer argues peaked right around the time the Neanderthals vanished. Ice core data suggest that from about 30,000 years ago until the last glacial maximum about 18,000 years ago, the Earth's climate fluctuated wildly, sometimes within the space of decades. A few more people in the social unit, with a few more skills, might have given modern humans an edge when conditions turned harsh. "Not a vast edge," Stringer said. "Neanderthals were obviously well adapted to a colder climate. But with the superimposition of these extreme changes in climate on the competition with modern humans, I think that made the difference."
Which leaves the final, delicate—and, as Jean-Jacques Hublin likes to say, politically incorrect—question that has bedeviled Neanderthal studies since the Out of Africa theory became generally accepted: Was the replacement by modern humans attenuated and peaceful, the Pleistocene version of kissing cousins, or was it relatively swift and hostile?
"Most Neanderthals and modern humans probably lived most of their lives without seeing each other," he said, carefully choosing his words. "The way I imagine it is that occasionally in these border areas, some of these guys would see each other at a distance…but I think the most likely thing is that they excluded each other from the landscape. Not just avoided, but excluded. We know from recent research on hunter-gatherers that they are much less peaceful than generally believed."
"Sometimes I just turn out the lights in here and think what it must have been like for them."
Evolutionary biologist Clive Finlayson, of the Gibraltar Museum, was standing in the vestibule of Gorham's Cave, a magnificent tabernacle of limestone opening to the sea on the Rock of Gibraltar. Inside, fantastic excretions of flowstone drooled from the ceiling of the massive nave. The stratigraphy in the cave is pocked with evidence of Neanderthal occupation going back 125,000 years, including stone spearpoints and scrapers, charred pine nuts, and the remains of ancient hearths. Two years ago, Finlayson and his colleagues used radiocarbon dating to determine that the embers in some of those fireplaces died out only 28,000 years ago—the last known trace of Neanderthals on Earth. (Other hearths in the cave may be as young as 24,000 years old, but their dating is controversial.)
From pollen and animal remains, Finlayson has reconstructed what the environment was like from 50,000 to 30,000 years ago. Back then, a narrow coastal shelf surrounded Gibraltar, the Mediterranean two or three miles distant. The landscape was scrub savanna scented with rosemary and thyme, its rolling sand dunes interrupted by the occasional cork oak and stone pine, with wild asparagus growing in the coastal flats. Prehistoric vultures, some with nine-foot wingspans, nested high up in the cliff face, scanning the dunes for meals. Finlayson imagines the Neanderthals watching the birds circle and descend, then racing them for food. Their diet was certainly more varied than the typical Neanderthal dependence on terrestrial game. His research team has found rabbit bones, tortoise shells, and mussels in the cave, along with dolphin bones and a seal skeleton with cut marks. "Except for rice, you've almost got a Mousterian paella!" Finlayson joked.
But then things changed. When the coldest fingers of the Ice Age finally reached southern Iberia in a series of abrupt fluctuations between 30,000 and 23,000 years ago, the landscape was transformed into a semiarid steppe. On this more open playing field, perhaps the tall, gracile modern humans moving into the region with projectile spears gained the advantage over the stumpy, muscle-bound Neanderthals. But Finlayson argues that it was not so much the arrival of modern humans as the dramatic shifts in climate that pushed the Iberian Neanderthals to the brink. "A three-year period of intense cold, or a landslide, when you're down to ten people, could be enough," he said. "Once you reach a certain level, you're the living dead."
The larger point may be that the demise of the Neanderthals is not a sprawling yet coherent paleoanthropological novel; rather, it is a collection of related, but unique, short stories of extinction. "Why did the Neanderthals disappear in Mongolia?" Stringer asked. "Why did they disappear in Israel? Why did they disappear in Italy, in Gibraltar, in Britain? Well, the answer could be different in different places, because it probably happened at different times. So we're talking about a large range, and a disappearance and retreat at different times, with pockets of Neanderthals no doubt surviving in different places at different times. Gibraltar is certainly one of their last outposts. It could be the last, but we don't know for sure."
Whatever happened, the denouement of all these stories had a signatory in Gorham's Cave. In a deep recess of the cavern, not far from that last Neanderthal hearth, Finlayson's team recently discovered several red handprints on the wall, a sign that modern humans had arrived in Gibraltar. Preliminary analysis of the pigments dates the handprints between 20,300 and 19,500 years ago. "It's like they were saying, Hey, it's a new world now," said Finlayson.
Last of the Neanderthals
Eurasia was theirs alone for 200,000 years.
Then the newcomers arrived.
Reconstruction by Kennis & Kennis/Photograph by Joe McNally
In March of 1994 some spelunkers exploring an extensive cave system in northern Spain poked their lights into a small side gallery and noticed two human mandibles jutting out of the sandy soil. The cave, called El Sidrón, lay in the midst of a remote upland forest of chestnut and oak trees in the province of Asturias, just south of the Bay of Biscay. Suspecting that the jawbones might date back as far as the Spanish Civil War, when Republican partisans used El Sidrón to hide from Franco's soldiers, the cavers immediately notified the local Guardia Civil.
But when police investigators inspected the gallery, they discovered the remains of a much larger—and, it would turn out, much older—tragedy.
Within days, law enforcement officials had shoveled out some 140 bones, and a local judge ordered the remains sent to the national forensic pathology institute in Madrid. By the time scientists finished their analysis (it took the better part of six years), Spain had its earliest cold case. The bones from El Sidrón were not Republican soldiers, but the fossilized remains of a group of Neanderthals who lived, and perhaps died violently, approximately 43,000 years ago. The locale places them at one of the most important geographical intersections of prehistory, and the date puts them squarely at the center of one of the most enduring mysteries in all of human evolution.
The Neanderthals, our closest prehistoric relatives, dominated Eurasia for the better part of 200,000 years. During that time, they poked their famously large and protruding noses into every corner of Europe, and beyond—south along the Mediterranean from the Strait of Gibraltar to Greece and Iraq, north to Russia, as far west as Britain, and almost to Mongolia in the east. Scientists estimate that even at the height of the Neanderthal occupation of western Europe, their total number probably never exceeded 15,000. Yet they managed to endure, even when a cooling climate turned much of their territory into something like northern Scandinavia today—a frigid, barren tundra, its bleak horizon broken by a few scraggly trees and just enough lichen to keep the reindeer happy.
By the time of the tragedy at El Sidrón, however, the Neanderthals were on the run, seemingly pinned down in Iberia, pockets of central Europe, and along the southern Mediterranean by a deteriorating climate, and further squeezed by the westward spread of anatomically modern humans as they emerged from Africa into the Middle East and beyond. Within another 15,000 years or so, the Neanderthals were gone forever, leaving behind a few bones and a lot of questions. Were they a clever and perseverant breed of survivors, much like us, or a cognitively challenged dead end? What happened during that period, roughly 45,000 to 30,000 years ago, when the Neanderthals shared some parts of the Eurasian landscape with those modern human migrants from Africa? Why did one kind of human being survive, and the other disappear?
On a damp, fog-shrouded morning in September 2007, I stood before the entrance to El Sidrón with Antonio Rosas of the National Museum of Natural Sciences in Madrid, who heads the paleoanthropological investigation. One of his colleagues handed me a flashlight, and I gingerly lowered myself into the black hole. As my eyes adjusted to the interior, I began to make out the fantastic contours of a karstic cave. An underground river had hollowed out a deep vein of sandstone, leaving behind a limestone cavern extending hundreds of yards, with side galleries spidering out to at least 12 entrances. Ten minutes into the cave, I arrived at the Galería del Osario—the "tunnel of bones." Since 2000, some 1,500 bone fragments have been unearthed from this side gallery, representing the remains of at least nine Neanderthals—five young adults, two adolescents, a child of about eight, and a three-year-old toddler. All showed signs of nutritional stress in their teeth—not unusual in young Neanderthals late in their time on Earth. But a deeper desperation is etched in their bones. Rosas picked up a recently unearthed fragment of a skull and another of a long bone of an arm, both with jagged edges.
"These fractures were—clop—made by humans," Rosas said, imitating the blow of a stone tool. "It means these fellows went after the brains and into long bones for the marrow."
In addition to the fractures, cut marks left on the bones by stone tools clearly indicate that the individuals were cannibalized. Whoever ate their flesh, and for whatever reason—starvation? ritual?—the subsequent fate of their remains bestowed upon them a distinct and marvelous kind of immortality. Shortly after the nine individuals died—possibly within days—the ground below them suddenly collapsed, leaving little time for hyenas and other scavengers to scatter the remains. A slurry of bones, sediment, and rocks tumbled 60 feet into a hollow limestone chamber below, much as mud fills the inside walls of a house during a flood.
There, buffered by sand and clay, preserved by the cave's constant temperature, and sequestered in their jewel cases of mineralized bone, a few precious molecules of the Neanderthals' genetic code survived, awaiting a time in the distant future when they could be plucked out, pieced together, and examined for clues to how these people lived, and why they vanished.
The first clue that our kind of human was not the first to inhabit Europe turned up a century and a half ago, about eight miles east of Düsseldorf, Germany. In August 1856 laborers quarrying limestone from a cave in the Neander Valley dug out a beetle-browed skullcap and some thick limb bones. Right from the start, the Neanderthals were saddled with an enduring cultural stereotype as dim-witted, brutish cavemen. The size and shape of the fossils does suggest a short, stout fireplug of a physique (males averaged about five feet, five inches tall and about 185 pounds), with massive muscles and a flaring rib cage presumably encasing capacious lungs. Steven E. Churchill, a paleoanthropologist at Duke University, has calculated that to support his body mass in a cold climate, a typical Neanderthal male would have needed up to 5,000 calories daily, or approaching what a bicyclist burns each day in the Tour de France. Yet behind its bulging browridges, a Neanderthal's low-domed skull housed a brain with a volume slightly larger on average than our own today. And while their tools and weapons were more primitive than those of the modern humans who supplanted them in Europe, they were no less sophisticated than the implements made by their modern human contemporaries living in Africa and the Middle East.
One of the longest and most heated controversies in human evolution rages around the genetic relationship between Neanderthals and their European successors. Did the modern humans sweeping out of Africa beginning some 60,000 years ago completely replace the Neanderthals, or did they interbreed with them? In 1997 the latter hypothesis was dealt a powerful blow by geneticist Svante Pääbo—then at the University of Munich—who used an arm bone from the original Neanderthal man to deliver it. Pääbo and his colleagues were able to extract a tiny 378-letter snippet of mitochondrial DNA (a kind of short genetic appendix to the main text in each cell) from the 40,000-year-old specimen. When they read out the letters of the code, they found that the specimen's DNA differed from living humans to a degree suggesting that the Neanderthal and modern human lineages had begun to diverge long before the modern human migration out of Africa. Thus the two represent separate geographic and evolutionary branches splitting from a common ancestor. "North of the Mediterranean, this lineage became Neanderthals," said Chris Stringer, research leader on human origins at the Natural History Museum in London, "and south of the Mediterranean, it became us." If there was any interbreeding when they encountered each other later, it was too rare to leave a trace of Neanderthal mitochondrial DNA in the cells of living people.
Pääbo's genetic bombshell seemed to confirm that Neanderthals were a separate species—but it does nothing to solve the mystery of why they vanished, and our species survived.
One obvious possibility is that modern humans were simply more clever, more sophisticated, more "human." Until recently, archaeologists pointed to a "great leap forward" around 40,000 years ago in Europe, when the Neanderthals' relatively humdrum stone tool industry—called Mousterian, after the site of Le Moustier in southwestern France—gave way to the more varied stone and bone tool kits, body ornaments, and other signs of symbolic expression associated with the appearance of modern humans. Some scientists, such as Stanford University anthropologist Richard Klein, still argue for some dramatic genetic change in the brain—possibly associated with a development in language—that propelled early modern humans to cultural dominance at the expense of their beetle-browed forebears.
But the evidence in the ground is not so cut and dried. In 1979 archaeologists discovered a late Neanderthal skeleton at Saint-Césaire in southwestern France surrounded not with typical Mousterian implements, but with a surprisingly modern repertoire of tools. In 1996 Jean-Jacques Hublin of the Max Planck Institute in Leipzig and Fred Spoor of University College London identified a Neanderthal bone in another French cave, near Arcy-sur-Cure, in a layer of sediment also containing ornamental objects previously associated only with modern humans, such as pierced animal teeth and ivory rings. Some scientists, such as British paleoanthropologist Paul Mellars, dismiss such modern "accessorizing" of a fundamentally archaic lifestyle as an "improbable coincidence"—a last gasp of imitative behavior by Neanderthals before the inventive newcomers out of Africa replaced them. But more recently, Francesco d'Errico of the University of Bordeaux and Marie Soressi, also at the Max Planck Institute in Leipzig, analyzed hundreds of crayon-like blocks of manganese dioxide from a French cave called Pech de l'Azé, where Neanderthals lived well before modern humans arrived in Europe. D'Errico and Soressi argue that the Neanderthals used the black pigment for body decoration, demonstrating that they were fully capable of achieving "behavioral modernity" all on their own.
"At the time of the biological transition," says Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis, "the basic behavior [of the two groups] is pretty much the same, and any differences are likely to have been subtle." Trinkaus believes they indeed may have mated occasionally. He sees evidence of admixture between Neanderthals and modern humans in certain fossils, such as a 24,500-year-old skeleton of a young child discovered at the Portuguese site of Lagar Velho, and a 32,000-year-old skull from a cave called Muierii in Romania. "There were very few people on the landscape, and you need to find a mate and reproduce," says Trinkaus. "Why not? Humans are not known to be choosy. Sex happens."
It may have happened, other researchers say, but not often, and not in a way that left behind any evidence. Katerina Harvati, another researcher at the Max Planck Institute in Leipzig, has used detailed 3-D measurements of Neanderthal and early modern human fossils to predict exactly what hybrids between the two would have looked like. None of the fossils examined so far matches her predictions.
The disagreement between Trinkaus and Harvati is hardly the first time that two respected paleoanthropologists have looked at the same set of bones and come up with mutually contradictory interpretations. Pondering—and debating—the meaning of fossil anatomy will always play a role in understanding Neanderthals. But now there are other ways to bring them back to life.
Two days after my first descent into El Sidrón cave, Araceli Soto Flórez, a graduate student at the University of Oviedo, came across a fresh Neanderthal bone, probably a fragment of a femur. All digging immediately ceased, and most of the crew evacuated the chamber. Soto Flórez then squeezed herself into a sterile jumpsuit, gloves, booties, and plastic face mask. Under the watchful eyes of Antonio Rosas and molecular biologist Carles Lalueza-Fox, she delicately extracted the bone from the soil, placed it in a sterile plastic bag, and deposited the bag in a chest of ice. After a brief stop in a hotel freezer in nearby Villamayo, the leg bone eventually arrived at Lalueza-Fox's laboratory at the Institute of Evolutionary Biology in Barcelona. His interest was not in the anatomy of the leg or anything it might reveal about Neanderthal locomotion. All he wanted from it was its DNA.
Prehistoric cannibalism has been very good for modern-day molecular biology. Scraping flesh from a bone also removes the DNA of microorganisms that might otherwise contaminate the sample. The bones of El Sidrón have not yielded the most DNA of any Neanderthal fossil—that honor belongs to a specimen from Croatia, also cannibalized—but so far they have revealed the most compelling insights into Neanderthal appearance and behavior. In October 2007 Lalueza-Fox, Holger Römpler of the University of Leipzig, and their colleagues announced that they had isolated a pigmentation gene from the DNA of an individual at El Sidrón (as well as another Neanderthal fossil from Italy). The particular form of the gene, called MC1R, indicated that at least some Neanderthals would have had red hair, pale skin, and, possibly, freckles. The gene is unlike that of red-haired people today, however—suggesting that Neanderthals and modern humans developed the trait independently, perhaps under similar pressures in northern latitudes to evolve fair skin to let in more sunlight for the manufacture of vitamin D. Just a few weeks earlier, Svante Pääbo, who now heads the genetics laboratory at the Max Planck Institute in Leipzig, Lalueza-Fox, and their colleagues had announced an even more astonishing find: Two El Sidrón individuals appeared to share, with modern humans, a version of a gene called FOXP2 that contributes to speech and language ability, acting not only in the brain but also on the nerves that control facial muscles. Whether Neanderthals were capable of sophisticated language abilities or a more primitive form of vocal communication (singing, for example) still remains unclear, but the new genetic findings suggest they possessed some of the same vocalizing hardware as modern humans.
All this from a group of ill-fated Neanderthals buried in a cave collapse, soon after they were consumed by their own kind.
"So maybe it's a good thing to eat your conspecifics," says Pääbo.
miércoles, 17 de septiembre de 2008
James Owen in London
Prehistoric cattle remains found close to Stonehenge suggest that partying pilgrims brought the animals from afar, scientists report.
The remains support a theory that the megalithic monument near Salisbury, in southern England, drew ancient peoples from distant regions to celebrate important feast ceremonies. And the feasts, it seems, were movable. The discovery is based on 4,500-year-old cattle teeth and bones recently unearthed at a late Stone Age village at Durrington Walls (learn more), less than two miles (three kilometers) from the famous stone circle.
"We are seeing physical evidence of the movement of populations into the [Stonehenge] area for the feasting," said Evans, a member of the research team.
Researchers analyzed isotopes, or different varieties, of atoms of the chemical element strontium that was preserved in the animals' tooth enamel. These atoms provide a chemical insight into the geology of the region where the animal lived.
The findings indicate all but one of the cattle studied were raised beyond the chalky, limestone-rich lands that surround Stonehenge and define much of southern England, Evans said.
And teeth samples from two cattle suggest they came from outside England altogether.
"These animals were grazing on soils that developed on relatively old rocks," Evans said, adding that the nearest locations where such rocks are found are Wales and Scotland.
Wales is the likelier of the two, Evans said, because it is closer to Stonehenge and has other archaeological connections. For instance, the Stonehenge monument includes bluestones that were transported from southwest Wales
The new findings, which have yet to be published, are based on the work of Sarah Viner, a graduate student who was working under the supervision of animal archaeologist Umberto Albarella at Britain's University of Sheffield.
The new chemical analysis wasn't precise enough to pinpoint the prehistoric cattle's exact origins, but the results prove that people were taking their livestock to Stonehenge from elsewhere in Britain, Albarella said.
"People were gathering from quite a large region," he said.
Furthermore, cattle bones excavated at the ancient settlement revealed no evidence of newborn calves. "If you have a site where animals were actually reared, you will almost certainly find a number of newborn casualties, but we are not finding that at all," Albarella said.
"So I'm pretty confident this is a consumer site," he added. "It is a site with a special purpose—where people are gathering, probably for feasting and eating an awful lot of meat."
Albarella is one of a large team of experts working on the Stonehenge Riverside Project, a continuing archaeological investigation led by Mike Parker Pearson, also from the University of Sheffield.
Parker Pearson, who has received funding from the National Geographic Society's Committee for Research and Exploration, proposes that Stonehenge and Durrington Walls were intimately connected. (The National Geographic Society owns National Geographic News.)
The archaeologist said the two sites had corresponding standing circles—one of stone, and one of timber—that symbolized the realms of the living and the dead to ancestor-worshipping ancient Britons.
(Related story: "Stonehenge Was Cemetery First and Foremost, Study Says" [May 29, 2008])
The hundreds of prehistoric dwellings recently discovered at Durrington are thought to represent a seasonal village that accommodated pagan pilgrims who came to celebrate the winter and summer solstices.
Prehistoric garbage dumps, or middens, were filled with evidence of Stone Age partying, such as pig and cattle bones and broken pottery.
Further study of livestock remains may support a new idea that pilgrims from different regions had their own quarters within the village.
It appears that the types of pottery differ in different areas of the site, based on fragments studied so far, Albarella said.
"It's a hypothesis which needs to be tested," he added. "We may be able to associate cattle [remains] coming from different areas of the site with, perhaps, different regions of origin."
Stonehenge researchers have turned to livestock as a proxy for studying the movement of people because few human teeth have been found in the area.
Human remains unearthed at the monument itself consist of cremation burials, and during cremation, teeth tend to explode, Albarella observed.
"We do need teeth, because it's the enamel in the teeth that preserve the [isotope] signal," said team member Evans.
miércoles, 10 de septiembre de 2008
The long-awaited start-up of the world's largest science experiment will begin tomorrow underneath villages and cow pastures at the French-Swiss border.
The Large Hadron Collider will smash protons at nearly the speed of light inside a circular, 17-mile (27-kilometer) long tunnel.
"It was first proposed more than 20 years ago," said Django Manglunki, an accelerator physicist at the European Organization for Nuclear Research (CERN). "We've been preparing that beam for more than ten years."
"It's difficult to realize that the machine, at last, is starting now," he added. (See photos of the collider.)
By creating hundreds of thousands of head-on collisions each second, physicists hope to understand the fiery conditions of the universe a trillionth of a second after the big bang.
The findings could also help resolve some of the biggest mysteries in physics, such as the existence of one long-hypothesized particle called the Higgs boson—or the "God particle"—thought to be responsible for giving all other particles their mass.
(Read about the God particle in National Geographic magazine.)
Another enigma that could be at least partially explained is dark matter, the invisible material thought to be the most common in the universe.
But first, researchers have to get the machine's beams of protons running.
Very Big Staircase
In several months CERN's physicists plan to use two beams, each with 2,808 bunches of protons, each of which contains a hundred billion protons—positively charged particles found in the nuclei of atoms.
Out of each collision, a spray of energy and other assorted particles will form. Scientists will study which particles show up, how often, and exactly how they fly out of the collisions. (Learn more about atom smashers.)
But on Wednesday, CERN scientists will first try to thread a single bunch of two billion protons through the collider.
"We will have a very low-intensity beam, so [in case of a problem] we can lose the beam without damaging the machine," Manglunki said.
Once the team gets the beam circulating all the way around the tunnel—which may happen in a couple of hours—the scientists will send in several bunches at a time.
Getting the first beam circulating, Manglunki said, is "one step in a very big staircase"—the long process of conceiving, designing, building, and finally running the experiment.
Although the physicists have done various tests on the machine already, "ultimately it's the beam that can tell you if everything is working," he added.
Later, they will attempt to get another beam of protons circulating through the tunnel in the opposite direction—a prelude to colliding the two beams.
Dark Matter Particle
In addition to spotting the Higgs boson, another early reward could be evidence of supersymmetry. The supersymmetry theory says that all the particles known today have much more massive—and as yet undetected—partners.
"There are strong reasons to believe that these new particles include the particle that makes up the cosmic dark matter that accounts for 80 percent of the matter in universe," said Michael Peskin, a particle physicist at the Stanford Linear Accelerator Center in Menlo Park, California.
The collisions could also create a zoo of new particles, experts say.
"If any of these theories are right, the LHC should be turning up the evidence for these particles by next summer," Peskin said.
But there could also be some big surprises.
"It might turn out to be like the 1950s, when we were discovering many new particles and had no clue about how they fit into a coherent picture," Peskin said.
"I hope it will turn out like that," he added. "This is what makes science fun."
No Cause for Alarm
Some people are worried that the experiments could also create unwelcome discoveries, such as particles and other exotic phenomena that could swallow up Earth or destroy the universe as we know it.
For instance, one possibility is that the collisions will pack matter together so tightly that it may collapse to form miniature black holes.
But reviews by both CERN physicists and independent researchers argue that, even if such black holes do form, there's no reason for alarm.
"Collisions just like those the [atom-smasher] will make have been produced by cosmic rays bombarding the Earth throughout its existence," said a statement from the American Physical Society.
The most energetic cosmic rays are particles that pack much more energy than those in the Large Hadron Collider—so much so that physicists still aren't sure how the most powerful cosmic rays get created. (See: "Black Holes Belch Universe's Most Energetic Particles" [November 8, 2007].)
Steve Giddings, a physicist at the University of California, Santa Barbara, is actually hoping miniature black holes do show up, along with other evidence supporting string theory—an unproven theory that describes subatomic particles as though they are tiny vibrating strings.
"It would be extremely exciting to see string properties directly. And that is possible if there are extra dimensions of space that are configured just the right way," Giddings said.
"[Seeing] all of this would be the ultimate jackpot scenario."
martes, 9 de septiembre de 2008
Richard A. Lovett
Supercontinents can form when a huge plume of hot rock from deep inside Earth wells up between the continental plates, pushing them apart until all Earth's landmasses collide.
This is the finding from a new study that suggests—contrary to accepted theory—that such a process formed the supercontinent Pangaea 300 million years ago. Today's continents are thought to have formed from Pangaea's gradual breakup.
Earth's shifting plates have been forming and breaking up supercontinents for billions of years, scientists believe, and traditionally they thought that suction is the driving force. (See an interactive map of Earth's tectonic plates.)
In seismically active places such as the Ring of Fire in the Pacific region, slabs of Earth's crust descend into the interior in a process called subduction.
This creates a downward current that sucks the continents into collision above it, like soapsuds being drawn together as water flows down a drain.
But in the new paper, J. Brendan Murphy of St. Francis Xavier University in Nova Scotia, Canada, and colleagues suggest that a plume of subducting crust in the middle of the ancestral Pacific Ocean descended so deeply it hit Earth's core.
Superheated, it then rebounded like a bubble in a boiling pot. That produced a superplume strong enough to push, not suck, the ancient continents back together and form Pangaea.
Peter Cawood, director of the Tectonics Special Research Centre at the University of Western Australia, called the finding "excellent and stimulating."
"Although provocative, I believe it is probably right," Cawood said by email.
Matching up rock types, examining magnetic signatures, and cataloging fossils have allowed scientists to trace the cycle of supercontinents forming and breaking apart back at least a billion years. Earth is believed to be about 4.5 billion years old.
The data show there were two supercontinents before Pangaea called Rodinia and Gondwana that formed and broke up hundreds of millions of years ago
The older supercontinent called Gondwana is different from the southern landmass known as Gondwanaland that formed 200 million years ago as Pangaea split apart.)
Wouter Bleeker, of the Geological Survey of Canada, has dubbed this cycle "the pulse of the Earth."
Murphy agrees. "Most people believe that for at least the last two and a half billion years, the Earth's history has been dominated by the amalgamation, breakup, and reforming of supercontinents," he said.
"It really is an underpinning of the evolution of the planet."
But according to Murphy's new study, published this month in the journal Geology, there's something wrong with the suction-driven model in the case of Pangaea.
The problem, he said, is that it's very clear from the geologic record that the formation of Pangaea from the fragments of Gondwana occurred in two stages.
First Gondwana split, producing a steadily widening "young" ocean in its heart, much like the Atlantic Ocean that now separates the fragments of Pangaea.
Then something shifted. Rather than continuing to widen, as it would if its motion was being driven by suction, the new ocean started to shrink. The continents reversed course and slammed back into each other to form Pangaea.
This accordionlike action, dubbed the Wilson Cycle, has been recognized for more than 40 years, but the forces responsible for it are unknown.
Moreover, if current models thought to be responsible for these movements were applied to a 500-million-year-old Earth, they would not produce Pangaea in the right configuration.
Why this reversal happened is unclear, and that's disconcerting, Murphy said, because even though Pangaea is the best studied of the supercontinents, "something happened that we don't understand."
(Related: "Ancient Imbalances Sent Earth's Continents 'Wandering'" [April 7, 2008].)
The new theory of a superplume interfering with the suction process could put the pieces of what occurred into place, although more data would be needed to cement the idea.
"It's speculative," Murphy said. "What we'd like people to get out of the article is that there's a fundamental problem in understanding how Pangaea formed."
Murphy added that his theory could have implications for the long-term future of the planet.
Right now the continents are converging on the mid-Pacific Ocean, where, if present motions continue, they will collide into a new supercontinent in about 75 to 80 million years.
But if Murphy's study is right, the process could reverse. North America could be driven back toward Europe, as happened in the formation of Pangaea.
Such a scenario, once thought unlikely, makes Earth's future a lot more fun to study, Murphy added.
lunes, 8 de septiembre de 2008
Mati Milstein at Kfar HaHoresh, Israel
Prehistoric graves with an unusual abundance of phallic figurines and oddly arranged human remains have been found in Israel, archaeologists announced recently.
Near Nazerat (Nazareth), the Stone Age site, called Kfar HaHoresh, dates to between 8,500 and 6,750 B.C. Stone Age Hand Axes Found at Bottom of North Sea (March 17, 2008)
The site was uninhabited and probably served surrounding villages as a centralized burial and cult center, said excavation leader Nigel Goring-Morris of Hebrew University's Institute of Archaeology.
Archaeologists have primarily found female symbolic figurines in other burials of this time period.
"At Kfar HaHoresh, all the gender-oriented symbolism seems to be male," Goring-Morris said. "Researchers in the past have put more emphasis on the 'mother goddess' of agriculture."
Among other oddities at the newly excavated site are human bones arranged into shapes and even buried with human remains.
Very Unusual Site
At least 65 individuals—mostly young males between the ages of 20 and 30—were found buried in plaster-surfaced structures. The largest measures 33 feet (10 meters) by at least 66 feet (20 meters).
"This is not a regular site," said Avi Gopher, an archaeologist at Tel Aviv University. "There are many burials and many of them are very unusual."
"Generally, we did not have central cemeteries during this period. … But there may well be places where the emphasis on burial was greater," added Gopher, who is not involved in the excavation.
The period between 8,500 and 6,750 B.C. was characterized by a transition from hunting and gathering to large, village-based agricultural communities that domesticated crops and livestock.
The people of Kfar HaHoresh were also dealing with fundamental societal change, archaeologists say.
One young male was found buried atop the remains of seven wild cattle.
It is likely among the first evidence of burial feasts, excavation leader Goring-Morris believes. Other people were buried with fox jaws.
"You have the first large-scale village communities with the beginnings of all the attendant problems we know today, such as land ownership and transfer of rights from one generation to the next," he said.
"An intensification of ceremonial practices would probably serve to alleviate some of the stresses and tensions within the society."
Also the shift in men's role from hunters to more settled herders and farmers may have reduced their status and self-image, Goring-Morris said. This may have led the prehistoric people to bury young male adults at Kfar HaHoresh with animals as a way of honoring their past lives as hunters.
"When societies are undergoing change, they sometimes prefer to look backwards instead of forwards," he said.
Some of the children buried at Kfar HaHoresh also received at least some of the same funerary treatments as adults, such as being buried with grave goods including pendants and fox jaws.
"As agriculture progressed and developed, symbolism developed in parallel," Tel Aviv University's Gopher added.
Skull on the Mantelpiece
The people at Kfar HaHoresh also manipulated bodies before burial.
Many of the bodies' skulls were removed postmortem, and their facial features were reconstructed with lime plaster.
(See related photos: "Headless Skeletons Reveal Ancient Ritual" [November 2007].)
"We are obviously dealing with preliterate societies," said Goring-Morris, who has received funding in the past from the National Geographic Society's Committee for Research and Exploration. (National Geographic owns National Geographic News.)
"If you have the skull of your grandfather or grandmother on the mantelpiece at home, this could be your legal document that you were the owner of the house or had certain legal rights, passed from one generation to the next."
The longer bones of a number of bodies were found arranged in shapes, one of which appears to depict an animal.
Researchers also found flint tools, axes, and incised tokens. Other discoveries included seashells and exotic minerals from across the eastern Mediterranean and Red Sea—finds that point to overland and maritime trade during the period
jueves, 4 de septiembre de 2008
Dozens of ancient, densely packed, towns, villages, and hamlets arranged in an organized pattern have been mapped in the Brazilian Amazon, anthropologists announced today.
The finding suggests that vast swathes of "pristine" rain forest may actually have been sophisticated urban landscapes prior to the arrival of European colonists.
Ancient "Lost City" Discovered in Peru, Official Claims (January 16, 2008)
Evidence of Ancient Towns Found in Amazon Basin (September 25, 2003)
"It is very different from what we might expect using certain classic models of urbanism," noted study co-author Michael Heckenberger, an anthropologist at the University of Florida in Gainesville.
Nevertheless, he said, the repeated patterns within and among settlements across the landscape suggest a highly ordered and planned society on par with any medieval European town.
The finding supports a controversial theory that the Amazon River Basin teemed with large societies that were all but obliterated by disease when European colonists arrived in the 15th and 16th centuries.
The isolated tribes that remain in the Amazon today are the last survivors of these once great societies, according to the theory.
If this theory is correct, the networked structure of the ancient settlements may lend insight to better protect and manage the indigenous populations and forests that remain in the Amazon today, scientists said.
In 1993, Heckenberger lived with the Kuikuro near the headwaters of the Xingu River. Within two weeks of his stay, he learned about the ancient settlements and began a 15-year effort to study and map them in detail.
So far he has identified at least two major clusters—or polities—of towns, villages, and hamlets. Each cluster contains a central seat of ritualistic power with wide roads radiating out to other communities.
Each settlement is organized around a central plaza and linked to others via precisely placed roads. In their heyday, some of the settlements were home to perhaps thousands of people and were about 150 acres (61 hectares) in size.
A major road aligned with the summer solstice intersects each central plaza.
Ancient "Lost City" Discovered in Peru, Official Claims (January 16, 2008)
Evidence of Ancient Towns Found in Amazon Basin (September 25, 2003)
The larger towns, placed at cardinal points from the central seat of power, were walled much like a medieval town, noted Heckenberger. Smaller villages and hamlets were less well defined.
Between the settlements, which today are almost completely overgrown, was a patchwork of agricultural fields for crops such as manioc along with dams and ponds likely used for fish farms.
"The whole landscape is almost like a latticework, the way it is gridded off," Heckenberger said. "The individual centers themselves are much less constructed. It is more patterned at the regional level."
At their height between A.D. 1250 and 1650, the clusters may have housed around 50,000 people, the scientists noted.
According to Heckenberger, the planned structure of these settlements is indicative of the regional planning and political organization that are hallmarks of urban society.
"These are far more planned at the regional level than your average medieval town," he said, noting that rural landscapes in medieval settlements were randomly oriented.
"Here things are oriented at the same angles and distances across the entire landscape."
The research "raises huge and important questions," Susan Hecht, an Amazon specialist at the University of California, Los Angeles, was quoted saying in a related Science news piece written by Charles Mann.
Mann is the author of the 2005 book 1491: New Revelations of the Americas Before Columbus, which describes theories of urban planning in the Amazon.
For one, Hecht was quoted as saying, the research adds further weight to the idea that the Amazon Basin once supported large and complex societies.
Other scientists, notably archaeologist Betty Meggers at the Smithsonian Institution in Washington, D.C., have argued that Amazonian soils were too poor to support large human populations for extended periods.
Hecht said the research also challenges the idea that urbanism means a central, dominant, and powerful city. Smaller, but highly connected settlements may also have been common.
According to study co-author Heckenberger, the clusters of towns in the pre-Columbian Amazon were similar to the system envisioned by British planner Ebenezer Howard in his 1902 book, Garden Cities of Tomorrow.
Howard argued for a system of tightly linked smaller cities instead of large megacities that are an eyesore on the natural world.
"If [he] knew about Xingu, it would have been a chapter in his book," Heckenberger said.
And now that the Amazonian "garden cities" have been found, Heckenberger added, scientists and planners ought to study them closely for alternatives to the modern system that is destroying vast reaches of the Amazon and displacing the last of the region's indigenous tribes.
"We know that we have to come up with alternatives," he said, "so here is a place we may want to look."
martes, 2 de septiembre de 2008
Platecarpus was a medium-sized mosasaur with long, narrow jaws lined with sharp, pointy teeth. This marine lizard grew to 24 feet (7 meters) in length and roamed the shallow seas of the Late Cretaceous in search of small fish and squid. Platecarpus was more selective in its diet than its larger and more ferocious relative Tylosaurus, a deadly hunter with eyes for anything that moved.
While not the biggest mosasaur, Platecarpus was one of the most abundant; its fossils have been found in ancient seabeds in North America, Europe, and Africa.
As with all mosasaurs, a long and muscular, vertically flattened tail powered Platecarpus through the water in snakelike fashion while flipper-like limbs provided the steering. Some fossilized specimens have thick eardrums, an adaptation that may have allowed the sea monster to chase fish into deep waters.