3rd Room of Ancient Greek Tomb Revealed

Archaeologists say they've had a peek inside another room in a monumental ancient tomb in Greek Macedonia that is believed to date back to the era of Alexander the Great.

The ongoing excavations at the Kasta Hill burial mound in Amphipolis -- about 65 miles (104 kilometers) east of Thessaloniki -- have generated excitement and speculation over what (and whom) archaeologists might find inside.

The latest images, released by the Greek Ministry of Culture yesterday (Sept. 14), show an arched, soil-filled room, with some traces of red paint on the limestone walls. The chamber lies beyond beyond the two female statues known as caryatids that were uncovered last week.

The Kasta Hill tomb is enclosed by an enormous wall whose perimeter measures 1,600 feet (490 meters). In August, archaeologists revealed two broken sphinxes at the entrance to the burial complex. Over the past several weeks, they've been removing soil and walls of heavy sealing stones to probe deeper into the tomb. They've discovered mosaic floors, and last week, the team uncovered the wavy-haired caryatids — statues that take the place of columns or pillars — standing guard at the second doorway.

The archaeologists, led by Katerina Peristeri, have said they believe the tomb dates back to the late fourth century B.C. and has the characteristics of a work by Dinocrates, Alexander the Great's chief architect. But excavators are unlikely to find the body of Alexander the Great himself; historical records indicate he was buried in Alexandria, though his body has never been found.

"This is an ongoing excavation; much more will be discovered as the excavation goes forward," Beth Carney, a history professor at Clemson University, told Live Science in an email. Carney, who is not involved in the excavation, said the tomb seems remarkable for its huge circumference and carved portals, but she isn't sure what evidence the archaeologists have for a late fourth century B.C. date.

The date of the tomb could prove important if archaeologists find bones inside that are tough to identify. Archaeologists have quarreled for decades over the identity of a couple buried in the lavish Macedonian tomb at Vergina in northern Greece, near the site of the early capital of the Kingdom of Macedonia. When Greek archaeologist Manolis Andronikos opened the grave (dubbed Tomb II) at Vergina in 1977, he claimed to have found the resting place of Alexander's father, Philip II, a powerful leader in his own right who paved the way for his son's conquests before he was assassinated in 336 B.C. But others have suggested that the tomb actually belonged to Philip III Arrhidaeus, Alexander's (perhaps mentally disabled) half-brother, who was executed in 317 B.C. after a less successful reign.

Read more at Discovery News

Dino-Killing Meteorite Gave Way to Leafy Forests

The meteorite that killed off the dinosaurs 66 million years ago had more of an effect on evergreens and led plants that lose their leaves to dominate forests, reports a new study.

The event wiped out about half of plant species, and fast-growing deciduous trees replaced evergreens, researchers from the University of Arizona report.

"When you look at forests around the world today, you don't see many forests dominated by evergreen flowering plants," said the study's lead author, Benjamin Blonder from the University of Arizona, in a statement. "Instead, they are dominated by deciduous species, plants that lose their leaves at some point during the year."

Blonder and his colleagues studied 1,000 plant leaves fossilized in southern North Dakota, which are stored at the the Denver Museum of Nature and Science.

"There is a spectrum between fast- and slow-growing species," Blonder said. "There is the 'live fast, die young' strategy and there is the 'slow but steady' strategy. You could compare it to financial strategies investing in stocks versus bonds."

Evergreens take more time to build their leaves and last a long time, the researchers reported. Deciduous plants die sooner, but they're able to move more water and acquire carbon faster.

"If you think about a mass extinction caused by catastrophic event such as a meteorite impacting Earth, you might imagine all species are equally likely to die," Blonder said. "Survival of the fittest doesn't apply — the impact is like a reset button. Our study provides evidence of a dramatic shift from slow-growing plants to fast-growing species."

From Discovery News

Schizophrenia Is Actually Eight Genetic Disorders

New research published in the American Journal of Psychiatry suggests that schizophrenia is not a single disease, but rather a group of eight genetically distinct disorders, each of them with its own set of symptoms. The finding could result in improved diagnosis and treatment, while also shedding light on how genes work together to cause complex disorders.

Schizophrenia is classified as a psychotic disorder, one characterized by an inability to discern what is real and not real, to think clearly, have normal emotional responses, and act normally in social situations. As Elyn Saks told us last year, "it's a waking nightmare, where you have all the bizarre images, the terrible things happening, and the utter terror -- only with a nightmare you open your eyes and it goes away. No such luck with a psychotic episode."

Scientists aren't entirely sure what causes it, nor does it manifest identically in all people who have it (leading to the broader diagnosis of being on the 'schizophrenia spectrum'). But links have been made to genetics, social factors (including early development), and neurobiology. The heritability link looks to be particularly promising, however; about 80 percent of the risk for schizophrenia is genetic. Yet scientists have struggled to identify which genes are responsible for the condition.

But a novel approach to analyzing genetic influences on more than 4,000 people with schizophrenia has finally allowed researchers to identify distinct gene clusters that contribute to eight different classes of schizophrenia.

"Genes don't operate by themselves," noted C. Robert Cloninger, MD, PhD, one of the study's senior investigators in a statement. "They function in concert, much like an orchestra, and to understand how they're working, you have to know not just who the members of the orchestra are but how they interact."

Indeed, complex diseases like schizophrenia may be influenced by hundreds or thousands of genetic variants that interact with one another in complicated and dynamic ways, leading to what scientists call "multifaceted genetic architectures." Now, thanks to the work of investigators at the Washington University School of Medicine in St. Louis, the genetic architecture for schizophrenia is starting to take shape.

For the study, Cloninger and his colleagues matched precise DNA variations in people with and without schizophrenia to symptoms in individual patients. In total, they looked at nearly 700,000 sites within the genome where a single unit of DNA is altered (i.e. a single nucleotide polymorphism, or SNP). Specifically, they analyzed the SNPs of 4,200 people with schizophrenia and 3,800 people without it. This allowed them to learn how individual genetic variations interact with each other to produce the illness.

So, for example, hallucinations and delusions were associated with one set of DNA variations, that carried a 95 percent risk of schizophrenia. Another symptom, disorganized speech and behavior, was found to carry a 100 percent risk with another set of DNA.

"What we've done here, after a decade of frustration in the field of psychiatric genetics, is identify the way genes interact with each other, how the 'orchestra' is either harmonious and leads to health, or disorganized in ways that lead to distinct classes of schizophrenia," Cloninger said.

When it comes to schizophrenia and other complex conditions, individual genes have only a weak and inconsistent association (which is why it's often silly to look for single-gene factors). But groups of interacting gene clusters create an extremely high and consistent risk of illness -- in this case, on the order of 70 percent to 100 percent. It's nearly impossible for people with these precise genetic variations to avoid the condition. In all, the researchers found no less than 42 clusters of genetic variations that significantly increase the risk of schizophrenia.

"In the past, scientists had been looking for associations between individual genes and schizophrenia," explained Dragan Svrakic, PhD, MD, a co-investigator and a professor of psychiatry at Washington University. "When one study would identify an association, no one else could replicate it. What was missing was the idea that these genes don't act independently. They work in concert to disrupt the brain's structure and function, and that results in the illness."

According to Svrakic, the key to the study was in organizing the genetic variations and the patients' symptoms into groups. This allowed them to see that particular clusters of DNA variations acted together to cause specific symptoms. Patients were then divided according to the type and severity of their symptoms. Results showed that those symptom profiles corresponded to eight qualitatively distinct disorders based on underlying genetic conditions.

Read more at Discovery News

Giant Dinosaur Could Fill Fossil 'Black Hole'

A giant dinosaur found in Tanzania once lived during a lush, green period when flowering plants flourished, about 100 million years ago, paleontologists report. The new dino species is a rare find in sub-Saharan Africa, where far fewer dinosaur fossils are discovered than in South America, the researchers said.

Paleontologists discovered the massive fossil in 2007 during fieldwork in the Rukwa Rift Basin in southwestern Tanzania.

Political instability in certain parts of Africa can prevent dinosaur digs, but fossils in this part of the world are also elusive for geological reasons. As the continents drifted apart, Africa did not move as much as the other continents did, leaving its fossils buried instead of pushed up by plate tectonics, said Patrick O'Connor, a professor of anatomy at Ohio University in Athens, Ohio, and one of the researchers on the new study.

Africa also had fewer ideal areas where sediment could quickly bury a creature and begin the fossilization process. Politics and geology, "those two things together account for why we don't know so much about continental Africa as we do about other parts of the world," O'Connor said.

Joseph Sertich, then a graduate student at Stony Brook University in Long Island, New York, and now a paleontologist at the Denver Museum of Nature & Science, was the first to spot the bones in the Rukwa Rift Basin.

"He scrambled into a gully and found the skeleton coming out the cliff surface," O'Connor said.

A careful excavation by local coal miners and paleontologists in 2007 and 2008 suggests that muddy elements had buried the dinosaur's remains — not once, but twice, O'Connor told Live Science. About 100 million years ago, the dinosaur likely died on a muddy floodplain. Mudstone eventually covered its body, but shortly after, a river running through the plain cut away at the mudstone, exposing part of the skeleton and encasing it in sandstone.

A river still runs near the site, and its drainage through the cliff face had begun to uncover the ancient skeleton, O'Connor said.

The researchers recovered about two dozen fossilized bones, enough to determine that they had a new species on their hands, O'Connor said. An analysis of the bones' shapes and features suggest the dinosaur was a titanosaurian, a member of the giant, long-necked and plant-eating sauropod dinosaurs.

The paleontologists named the dinosaur Rukwatitan bisepultus for the Rukwa Rift Basin and its titanosaurian roots — an allusion to the powerful and mythical Greek Titan deities. In Latin, bisepultus means "twice buried," said Eric Gorscak, the study's lead researcher and a doctoral candidate of biological sciences at Ohio University.

"A lot of what we know about titanosaurian evolution and their biology stems from South America, where there's a lot of specimens," Gorscak said. Titanosaurian remains are found on every continent including Antarctica, but "the early evolutionary history outside of South America is fuzzy."

The new finding helps bridge that gap, said Matthew Lamanna, a curator of vertebrate paleontology at the Carnegie Museum of Natural History in Pittsburgh, who was not involved with the study.

Rukwatitan is important because it's "one of the very few Cretaceous-aged dinosaurs known from Africa south of the Sahara Desert," Lamanna told Live Science in an email. "That part of the world is one of the biggest 'black holes' in our understanding of dinosaurs," he said.

Previously, paleontologists found thetitanosaurian Malawisaurus dixeyi in Malawi, but the Rukwatitan fossils are markedly different in shape and size from that specimen and other titanosaurians found in northern Africa, O'Connor said.

Rukwatitan weighed between 10 and 15 tons — about as much as two elephants but not nearly as much as Dreadnoughtus schrani, another type of titanosaurian, discovered in Argentina, that weighed about 65 tons, Gorscak said. He and his colleagues used a computed tomography (CT) scan to view Rukwatitan's bones and its internal structure. Like other titanosaurians and meat-eating theropods — dinosaurs that may have given flight to birds — Rukwatitan's neck bone was hollow and filled with air.

Read more at Discovery News

Ancient Giant Sloth Species Got Huge Fast

An ancient sloth weighing some 5 tons and sporting claws that extended a foot (0.3 meters) is helping to reveal how the slow, furry creatures ballooned in size long ago at a startlingly fast rate, a new study finds.

The massive beast, Eremotherium eomigrans, along with all of the sloth's giant predecessors, went extinct by about 11,000 years ago.

The new study found that some sloth lineages grew more than 220 pounds (100 kilograms) every million years — one of the fastest body growth rates known in the evolution of mammals. The rapid growth rate indicates that several factors in prehistoric times, such as environmental conditions or competition with other animals, may have favored large sloths, the researchers said in a statement.

Other studies have examined sloth growth rates, but accounted for only living species. The researchers incorporated extinct sloths into the equation for the new study to show that the animals grew at an incredibly fast rate over time.

There are six species of sloths living in South America today, which reach a maximum weight of about 12 lbs. (6 kg). However, the fossil record shows a richer diversity, with more than 50 known species that lived between about 2.6 million and 11,700 years ago. In all, the researchers looked at 57 species of sloths that are living or from the fossil record, and examined the average changes in body mass throughout their evolution, the study reported.

"Today's sloths are really the black sheep of the sloth family," study co-author Anjali Goswami, of the University College London earth sciences department, said in a statement. "If we ignore the fossil record and limit our studies to living sloths, as previous studies have done, there's a good chance that we'll miss out on the real story and maybe underestimate the extraordinarily complex evolution that produced the species that inhabit our world."

Nowadays, sloths are vegetarians that live in trees and typically weigh between 8 and 12 pounds (3.5 and 5.5 kg), the researchers said. In contrast, extinct sloths lived in a range of environments, and included ground-, tree- and water-dwelling sloths. Fossilized footprints suggest that some of these ancient sloths walked on their hind legs, and may have also eaten both plants and animals.

Read more at Discovery News

Egypt's Ancient Animals Killed by Climate and Civilization

If you took a cruise along the northern stretch of the Nile some 6,000 years ago, you wouldn't have seen any pyramids, but you might have spotted a giraffe or an elephant taking a drink at the bank of the river.

At that time, the Nile wasn't surrounded by desert; rather, the warmer, wetter landscape resembled the current scenery of sub-Saharan East Africa.

Today, Egypt's elephants and giraffes are extinct. So are its cheetahs and aurochs and wildebeests. But animal bones and images of animals on ancient artifacts reveal what creatures once roamed the region. A team of researchers looked at Egypt's rich archaeological record and found that most mammal extinctions over the last six millennia were linked to periods of big change in terms of climate and human civilization.

Justin Yeakel -- a researcher out of the University of California, Santa Cruz, who is now a postdoctoral fellow at the Santa Fe Institute in New Mexico -- said the work was first inspired by a trip with a colleague to see a traveling exhibit on King Tutankhamun while it was in San Francisco a few years ago.

"We were just amazed at the diversity of animals in the artifacts," Yeakel told Live Science. "It got us thinking about how we could use representations of animals in the historical record to understand how animal communities have changed."

Egypt turned out to be a good area for a case study, because the area has been occupied continuously for thousands of years and has an extensive archaeological record. There are rock art drawings of hippopotamuses and rhinoceroses from the early Holocene. The tombs of Egyptian pharaohs are decorated with hunting scenes that show which creatures would have been prized prey. Import records of cheetahs and lions reveal when certain animals might have been considered exotic after disappearing locally.

The researchers found that Egypt was home to 37 large-bodied mammals (those over 8.8 lbs., or 4 kilograms) during the Late Pleistocene and early Holocene. Today, just eight of those creatures remain: the golden jackal, the ibex, the Barbary goat, the Egyptian fox, the Dorcas gazelle, the wild ass, the striped hyena and the slender-horned gazelle, which is on the verge of extinction.

"Our simplest observation was that the community changed in a very nonrandom way," Yeakel said.

The stability of the ecosystem tended to unravel during periods of major climate change and socio-political turnover, the scientists found. When the so-called African Humid Period ended about 5,000 years ago, Egypt's landscape switched to a drier, desert-like climate; around the same time, humans started farming and ancient Egypt's Dynastic Period began. Another aridification period occurred about 4,170 years ago and has been linked to the collapse of Egypt's Old Kingdom, the period that saw the first pyramids. A third drying period has been linked to the fall of the New Kingdom in Egypt about 3,000 years ago.

Yeakel said he and his fellow researchers can't really tease apart the possible causes that led to these ecological changes. But the scientists have identified the potential drivers. During the first big change after the African Humid Period, for example, human populations grew and overhunting might have driven the decline of large herbivores -- such as elephants, giraffes and native camels -- which then indirectly affected the populations of the predators that ate the herbivores. Agriculture was also on the rise during this period. Most of the region's nutrients were concentrated in the Nile floodplain, and competition with farmers might have also hurt herbivore populations. A third possible driver could have been the climate; the drier environment might have limited the availability of plants at the bottom of the food chain.

Read more at Discovery News

Ancient Mexican Tequila Worked as Food, Energy Drink

Less than an hour's drive from the heart of Mexico City lies the expansive ruins of Teotihuacan, a massive city of nearly 120,000 people who built pyramids, temples and palaces before disappearing around 650 A.D.

This civilization, which pre-dates the Aztecs, remains a mystery in many ways. But new research has found they brewed a tequila-like drink called pulque as a source of food and nutrition, not just to forget their woes.

Pulque is a milky-white liquor made from the maguey plant -- a relative of the agave used in tequila -- and is still popular among local residents. Traces of pulque have been found on pottery shards dating at Teotihuacan dating back to 150 B.C., according to a new study published today in Proceedings of the National Academy of Sciences.

Pulque was not just reserved for the upper classes, according to Marisol Correa-Ascencio, a doctoral student in chemistry at the University of Bristol (UK) and first author on the paper.

"The beverage was consumed by greater part of the population," Correa-Ascencio said. "It could have helped to compliment the diet of the people."

While ancient Egyptian and Mesopotamian cultures brewed beer and wine before the rise of the Teotihuacan culture, this is the earliest finding of an alcoholic beverage in Mesoamerica, Correa-Ascencio said.

Her colleagues used a new approach to identifying chemical residue on the pottery using a lipid biomarker, or a tiny fat molecule that had bonded with the ceramic molecules of the vase-like amphoras that held the pulque and were sealed with pine resin.

"The principle is that when you process food like cooking or storing, the lipids are absorbed into the ceramic matrix and get encapsulated," Correa-Ascensio said. "We take a potsherd, clean it, crush it and then perform lipid extraction."

The researcher said this is the first time this method has been used to identify an ancient alcoholic beverage. Pulque was widely used by the Aztecs at the time of the Spanish conquest in 1521, and remains in use today.

One expert on the Teotihuacan people says the method could be used to research the history of other cultures use of alcohol.

Read more at Discovery News

Viking Fortress Reveals 'Fierce Warriors' Were Decent Architects

The Vikings weren't just a fierce band of warriors with cool headgear. A new archaeological discovery in Denmark suggests that these notorious fighters were also decent builders.

Archaeologists on the Danish island of Zealand recently discovered a Viking fortress that likely dates back to the 10th century A.D. It's the first time in 60 years that such a fortress has been unearthed in Denmark, the researchers said.

"The Vikings have a reputation as [fierce Norse warriors] and pirates. It comes as a surprise to many that they were also capable of building magnificent fortresses," Søren Sindbæk, a professor of medieval archeology at Aarhus University in Denmark, said in a statement. The discovery of the new fortress provides an opportunity for archaeologists to gain even more knowledge about Viking wars and conflicts, Sindbæk added.

Prior to this latest discovery, three other Viking fortresses were discovered in Denmark. These structures, named Fyrkat, Aggersborg and Trelleborg, are known collectively as the "Trelleborg" fortresses.

"We recognize the 'Trelleborg' fortresses by the precise circular shape of the ramparts and by the four massive gates that are directed at the four corners of the compass," said Nanna Holm, curator of the Danish Castle Centre in Denmark, who helped identify the site of the newly unearthed fortress. "Our investigations show that the new fortress was perfectly circular and had sturdy timber along the front. We have so far examined two gates, and they agree exactly with the 'Trelleborg' plan."

The fortress, located south of the capital city of Copenhagen, is huge, Holm said. It spans nearly 476 feet (145 meters) across, longer than 1.5 football fields.

Archaeologists long suspected that a fourth Trelleborg fortress might exist on the island of Zealand, according to Sindbæk, who has studied these structures for years. And the site of Vallø, now part of the Zealand Region on the east coast of Zealand, is an ideal place for the Vikings to have built such a structure, Sindbæk said.

During the 10th century, Vallø marked the spot where two main roads met, Sindbæk said. It also overlooked the Køge river valley, which at that time was a navigable fjord and one of the best natural harbors on the island, Sindbæk added.

Suspecting a fortress might be buried beneath Vallø, the team of archaeologists used advanced laser and magnetic tools to determine the structure's exact location. The team included Helen Goodchild from the University of York, in the United Kingdom.

"By measuring small variation in the Earth's magnetism, we can identify old pits or features without destroying anything," Sindbæk said. "In this way, we achieved an amazingly detailed 'ghost image' of the fortress in a few days. Then we knew exactly where we had to put in excavation trenches to get as much information as possible about the mysterious fortress."

Read more at Discovery News

Big Cats Eating Dogs, Leopard Poop Reveals

Leopards that roam rural India have a surprising favorite food: dogs. The big cats even seem to prefer eating domestic dogs in areas where cows, goats and other farm animals are plentiful, according to a new study.

To reconstruct leopard diets, scientists had to take a close look at leopard poop. A team led by researchers with the Wildlife Conservation Society scooped up 85 leopard fecal samples as they scoured footpaths, dried-up streams and fields in a rural section of western Maharashtra (the same state where Mumbai is located). Back in a lab, the researchers looked for signs of claws, hoofs and hair and other indigestible parts of unlucky prey in the scat.

The researchers found that domestic dogs were by far the most common prey, making up 39 percent of the leopards' diet (in terms of biomass). The remains of domestic cats were found in 15 percent of poop samples and accounted for 12 percent of the mass of leopards' meals.

By comparison, livestock were a relatively small portion of the leopard diet. Domestic goats, for example, accounted for just 11 percent of the mass of the big cats' meals, even though they were seven times more abundant than dogs in the study area.

All told, 87 percent of the leopards' diet was made up of domestic animals, including both livestock and pets; this suggests the leopards, though considered wild, are completely dependent on human-related sources of food. The small portion of the wild animals in the leopards' diet consisted of mostly rodents, as well as civets, monkeys, mongooses and birds.

The study illustrates just how big of an impact people have on the lifestyle of leopards that live in human-dominated landscapes. The largely agricultural study area around the town of Akole did not contain any natural patches of forest, and the nearest protected area was the Kalsubai Harishchandragad Wildlife Sanctuary, 11 miles (18 kilometers) to the west.

The researchers speculated that domestic animals make easier prey, because they lack anti-predatory behavior, unlike their wild counterparts. And free-roaming dogs might be particularly easy targets, because they likely are not as heavily guarded as economically valuable livestock.

Read more at Discovery News

Earthquake Unleashes Avalanche Over Glacier

An earthquake that rattled remote parts of Alaska and northwestern Canada in July triggered an avalanche that spilled mounds of snow down a steep mountainside. NASA scientists flying over the region captured dramatic photos of the quake-induced landslide just days after the event.

A 6.0-magnitude earthquake shook sections of Alaska and Canada's Yukon Territory on July 17. The quake struck Seward Glacier, which is located 62 miles (100 kilometers) from the Alaskan city of Yakutat, reported the Alaska Earthquake Information Center.

NASA scientists based in Fairbanks, Alaska, flew near Seward Glacier one day before the quake, on July 16, and observed that an earlier landslide had strewn rocks and other debris across the icy slopes. Four days after the earthquake, on July 21, the scientists revisited the site and discovered that a quake-induced avalanche had blanketed the mountainside in snow, covering much of the previous landslide's rocky trail.

"It's obvious that many big debris and snow slides happened in this short time window," NASA glaciologist Kelly Brunt said in a statement. "This is a super steep area, so you get a lot of activity here. The bulk of the activity in this case is probably associated with the July 17 quake."

Brunt and her colleagues snapped photos of the earthquake's aftermath using a digital camera mounted inside the nose cone of NASA's high-altitude ER-2 aircraft. The researchers flew within 1.2 miles (2 km) of the earthquake's epicenter.

The scientists were already scheduled to conduct flights over Alaska, near Seward Glacier, to test an instrument called the Multiple Altimeter Beam Experimental Lidar (MABEL), which is designed to detect changes in Earth's landscape — particularly Arctic sea ice — using lasers and photon detectors.

Read more at Discovery News