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Ancient snakes living on Madagascar
Mutations in the genes record the history of these blurry-eyed serpents. The genetic research reveals that the original stock of worm-like snakes arose on Gondwana, the ancient southern supercontinent. The initial split occurred about 155 million years ago as Gondwana divided into East Gondwana (the landmasses of Antarctica, India, Madagascar, and Australia) and West Gondwana (the landmasses of South America and Africa). The residents of East Gondwana -- the blindsnakes -- then diverged into several lineages including a new family named in this study and found only on Madagascar. Later, East Gondwana further divided into a new paleolandmass -- called by the researchers "Indigascar" (India plus Madagascar) -- and another comprised of Australia and Antarctica. The research suggests that the new family on Madagascar arose as a result of the break-up of the Indigascar landmass about 94 million years ago.
Madagascar's long isolation has led to the evolution of many unique endemic animals including this family of blindsnakes, various lemurs, and other rare mammals. Unfortunately, both the animals and plants of Madagascar are now endangered by habitat loss. Says team member Miguel Vences, a professor at the Technical University of Braunschweig, Germany, and authority on the biodiversity of Madagascar, "Finding such ancient roots for a group of animals in Madagascar gives us even more reason to protect their rapidly declining habitat."
If blindsnakes got their start on Indigascar, leaving an endemic living family as evidence on Madagascar, how did they get to all of those other places in the world that they occupy today -- Europe, Asia, Australia, Africa, and the Americas?
The phylogeny constructed by the Hedges and Vidal team shows a series of diversifications within the blindsnakes, outside of Madagascar, that occurred between 63 and 59 million years ago. The period of greatest diversification coincided with a time of low sea levels, when connections between continents were forming and the dispersal of such unlikely animals by floating on flotsam was easier. Blindsnakes must have moved either out of Africa via Europe and Asia -- the ancient northern supercontinent Laurasia -- or out of India and then from southeast Asia to Australia at about 28 million years ago. Since there were no land connections between Asia and Australia at this time, these blindsnakes could have reached Australia only by crossing the ocean on floating flotsam. After that point, the splits within the blindsnakes probably occurred because they were following the evolution and spread of their prey -- ants and termites -- in various geographic regions.
Floating across oceans seems an unlikely mechanism for a burrowing animal to spread to new continents, but there is a second instance of ocean crossing by blindsnakes among the groups left on West Gondwana: West Gondwana broke up about 100 million years ago, making Africa and South America separate continents, but the genetic split between African and South American blindsnakes occurred only at about 63 million years ago. This finding shows that blindsnakes probably were confined to Africa when West Gondwana broke up and only later traveled to South America -- and still later to the West Indies -- by floating across the Atlantic from east to west.
This journey has rarely been documented. Only six or seven other vertebrates are thought to have crossed the Atlantic in a westward direction. However, the crossing would have taken no more than six months and might not have been too difficult for blindsnakes, which have a relatively low need for food and may have been floating on vegetation rafts along with their insect prey.
"Some scientists have argued that oceanic dispersal is an unlikely way for burrowing organisms to become distributed around the world," observes Hedges. "Our data now reinforce the message that such 'unlikely' events nonetheless happened in evolutionary history."
Wednesday, March 31, 2010 | 0 Comments
Ancient doorway to afterlife discovered in Egypt
The door, 1.75 metres (5.7 feet) high and 50 cm (19 inches) thick, is engraved with religious texts and various titles used by User, including mayor of the city, vizier and prince, antiquities chief Zahi Hawass was quoted as saying.
"The newly discovered door was reused during the Roman period. It was removed from the tomb of User and used in the wall of a Roman structure," said Mansur Boraik, who headed the excavation mission.
Hatshepsut, who ruled Egypt between 1479 BC and 1458 BC, was the longest reigning female pharaoh.
QMI
Tuesday, March 30, 2010 | 0 Comments
Scientists find first ever southern tyrannosaur dinosaur
According to Dr Roger Benson of the Department of Earth Sciences at the University of Cambridge, who identified the find: "The bone is unambiguously identifiable as a tyrannosaur because these dinosaurs have very distinctive hip bones."
The discovery lays to rest the belief held by some scientists that tyrannosaurs never made it to the southern continents.
"This is an exciting discovery because tyrannosaur fossils had only ever been found in the northern hemisphere before and some scientists thought tyrannosaurs never made it down south.
"Although we only have one bone, it shows that 110 million years ago small tyrannosaurs like ours might have been found worldwide. This find has major significance for our knowledge of how this group of dinosaurs evolved." says Dr Benson.
Dr Paul Barrett, Palaeontologist at the Natural History Museum, London and member of the research team commented: "The absence of tyrannosauroids from the southern continents was becoming more and more anomalous as representatives of other 'northern' dinosaur groups started to show up in the south. This find shows that tyrannosauroids were able to reach these areas early in their evolutionary history and also hints at the possibility that others remain to be discovered in Africa, South America and India."
The bone would have come from an animal about three metres long and weighing around 80 kg, similar to a human, and would have had the large head and small arms that make tyrannosaurs so distinctive.
The newly identified dinosaur, known as NMV P186069, was much smaller than T. rex, which was 12 metres long and weighed around four tonnes. Giant size like this only evolved late in the tyrannosaur lineage.
Compared with T. rex, which lived about 70 million years ago at the end of Cretaceous period, NMV P186069 lived earlier during the Cretaceous, around 110 million years ago.
During the time of the dinosaurs the continents gradually went from a single supercontinent towards something like their present-day arrangement. This tyrannosaur is from the mid-stages of this continental break-up, when the southern continents of South America, Antarctica, Africa and Australia had separated from the northern continents, but had not separated from each other.
While answering the question of whether or not tyrannosaurs lived in both the southern and northern hemispheres, the new find leaves another, deeper mystery: why did tyrannosaurs evolve into giant predators such as T. rex only in the northern hemisphere?
According to Dr Benson: "It is difficult to explain why different groups succeeded in the north and the south if they originally existed in both places. What we need to know now is just how diverse the early radiation of tyrannosaurs was, why they went extinct, leaving only giant-sized, short-armed species like T. rex, and how successful they might have been in the southern hemisphere. We can only answer these questions with new discoveries."
Monday, March 29, 2010 | 0 Comments
A new fossil species found in Spain
The fossils have been found in the archaeological site El Membrillar (Badajoz), one of the few sites in Europe where remains of Cloudina can be found. "The specimens display exceptional preservation, they appear preserved in three dimensions, and show their original form and numerous details of the shells", Cortijo points out.
The discovery of new species of Cloudina is important "for understanding the early evolution of animals", states Cortijo, who adds that "its importance for understanding the origin of skeletons is indisputable". Despite the fact that its relation to other groups of animals is uncertain, Cloudina has been compared to cnidaria (medusas and corals) and annelida (polychaeta sea worms, earthworms and leeches).
According to the research team, the study of fossils from the Ediacaran period (between 630 and 540 million years ago) and of other fossils from the early Cambrian (540 million years ago) reveals the path followed by evolution at a crucial moment in the history of life, when the first animals appeared. This first evolutionary radiation of animals reached its apex in the so-called "great Cambrian explosion" or "Big-Bang of evolution".
In search of Cloudina
In the '70s specimens of Cloudina were discovered for the first time in Namibia and later they were discovered in Oman, southern China and the south-east of the USA. According to scientists, it is a fossil indicative of the terminal Ediacaran, which marks the end of the Proterozoic eon, and gives way to the Phanerozoic, when the great radiation of animals began.
In Spain Cloudina was discovered in the '80s thanks to Teodoro Palacios, director of the research group Palaeontology and Stratigraphy of the Neoproterozoic and Palaeozoic at the University of Extremadura.
Friday, March 26, 2010 | 0 Comments
New ancestor? Scientists ponder DNA from Siberia
Instead, it suggests the Siberian species lineage split off from the branch leading to moderns and Neanderthals a million years ago, the researchers calculated. And they said that doesn't seem to match the history of human ancestors previously known from fossils.
So the Siberian species may be brand new, although the scientists cautioned that they're not ready to make that claim yet.
Other experts agreed that while the Siberian species may be new, the case is far from proven.
"We really don't know," said Ian Tattersall of the American Museum of Natural History in New York, who wasn't involved in the new research.
But "the human family tree has got a lot of branchings. It's entirely plausible there are a lot of branches out there we don't know about."
The discovery "is like many new finds," said Eric Delson of Lehman College of the City University of New York, who didn't participate in the new work. "You say, `I think this is different, but I'm not sure.' And then you look for more material and you try to make better comparisons."
The researchers, who say the Siberian species is not a direct ancestor of modern-day people, hope further genetic analysis will show if it's a new species. Some experts are skeptical about whether such analysis will resolve that.
In any case, the finding emphasizes that quite unlike the present day, anatomically modern humans have often lived alongside their evolutionary relatives, one expert said.
"We weren't alone," said Todd Disotell of New York University, who was familiar with the new work. "When we became modern, we didn't instantly replace everybody. There were other guys running around who survived quite well until very, very recently."
Just last month, other researchers used DNA analysis to show the genetic diversity still present in residents of Africa, the cradle of the human race. And another project produced the first genome of an ancient human — a man who lived in Greenland some 4,000 years ago.
The new work, published online Wednesday by the journal Nature, is reported by Johannes Krause and Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and others.
They describe mapping DNA from what appeared to be a youngster's pinkie finger bone, which had been recovered in 2008 from Denisova Cave in Altai Mountains of southern Siberia. They showed how it differed from DNA of 54 modern-day people and six Neanderthals.
Their analysis indicated the Siberian species last shared a common ancestor with modern humans and Neanderthals about 1 million years ago. That in turn suggested there was a previously unrecognized migration out of Africa around that time, they said.
The work decoded the complete set of DNA from mitochondria, the power plants of cells. That's different from the better-known DNA that comes from cell nuclei and determines things like eye color. Paabo said the researchers are working to decode nuclear DNA from the Siberian species. That will reveal whether it was closely related to Neanderthals or today's humans, and answer questions like whether it interbred with Neanderthals or ancestors of modern-day people, he said.
Without a completed analysis of the nuclear DNA, "we are not saying this is a new species," Paabo said, although he said that's a likely possibility.
Rick Potts, director of the Smithsonian Institution's Human Origins Program, said the Siberian find might represent Homo heidelbergensis or Homo erectus. And even analysis of the Siberian species' nuclear DNA won't show if it's distinct from those ancestors, he said.
As for the study's suggestion of a migration out of Africa about a million years ago, Potts said there's already evidence of one or two migrations around that time.
The finger bone recovered from the Siberian species is not enough for a fossil-to-fossil comparison with other ancient species to show whether it's a new species, Delson said.
He suspects it might be a descendant of Homo erectus that's already documented in some fossil remains in northern Africa and Europe. Scientists are still trying to figure out how many species of the Homo grouping those bones represent and what name or names to attach to them, he said.
Disotell said the new creature could be an early version of Homo antecessor, a forerunner of Neanderthals and modern humans known from fossils in Spain. Or, he said, it could be a new species. In fact, the eventual decision could hinge mostly on the philosophical question of just how different a creature has to be to be declared a new species, he said.
Potts said that in the new work, "what we're seeing is a really, really interesting distant echo of the DNA history of human evolution.... This is an amazingly powerful technique that these guys have. This is going to be a growth industry in the study of human evolution."
MIA
Thursday, March 25, 2010 | 0 Comments
New dinosaur species found in Utah sandstone
Named Seitaad ruessi, the species was 10-to-15 feet long and 3-to-4 feet high. It's bones were found protruding from sandstone at the base of a cliff, directly below an ancient Anasazi cliff dwelling.
No humans were around at the time of the dinosaurs, but researchers say the bones could well have been visible when the early Indians lived there.
The name Seitaad comes from the word "Seit'aad," which was a sand monster that buried its victims in dunes in Navajo legend, according to the researchers. The newly named skeleton had been swallowed by a sand dune.
So, might visible dinosaur remains have given rise to the ancient Indian monster legend?
"That's a lot of speculation, but anything's possible," said Mark Loewen, a paleontologist at the Utah Museum of Natural History and instructor in the Department of Geology and Geophysics at the University of Utah.
One of the Anasazi dwellings included a stone with a dinosaur footprint in its center, he noted.
The ruessi part of the name is in honor of poet and naturalist Everett Ruess who disappeared in southern Utah in 1934.
Understanding how dinosaurs lived in the past, how their environments changed and affected them, is important for understanding our changing world today, Loewen said.
The nearly complete skeleton is missing only its head, one toe and a lower shinbone, he said, noting erosion over the years probably accounts for the missing parts.
What the researchers have is similar to other sauropodomorphs found in South America and southern Africa, which were all vegetarians, he explained in a telephone interview. However, Seitaad did have a claw on its front limbs, which Loewen suggested was probably used for defense.
"We were absolutely shocked" by the discovery of this dinosaur, Loewen said. It was found in 2004 by a local artist studying rock paintings and the scientists went to the area immediately when they learned of it, he said. The bones were excavated the following year by Museum researchers.
While dinosaur remains have been found in other parts of Utah fossils are rare in the Navajo sandstone areas and generally have been from smaller creatures.
"This new find suggests that there may be more dinosaurs yet to be discovered in these rocks," said Joseph Sertich, co-author of the report and currently a doctoral student at New York's Stony Brook University.
Wednesday, March 24, 2010 | 0 Comments
University of Kansas researcher investigates mysterious stone spheres in Costa Rica
His report will help determine if sites linked to the massive orbs will be designated for preservation and promotion because of their "outstanding value to humanity."
Hoopes, who researches ancient cultures of Central and South America, is one of the world's foremost experts on the Costa Rican spheres. He explained that although the stone spheres are very old, international interest in them is still growing.
"The earliest reports of the stones come from the late 19th century, but they weren't really reported scientifically until the 1930s — so they're a relatively recent discovery," Hoopes said. "They remained unknown until the United Fruit Company began clearing land for banana plantations in southern Costa Rica."
According to Hoopes, around 300 balls are known to exist, with the largest weighing 16 tons and measuring eight feet in diameter. Many of these are clustered in Costa Rica's Diquis Delta region. Some remain pristine in the original places of discovery, but many others have been relocated or damaged due to erosion, fires and vandalism.
The KU researcher said that scientists believe the stones were first created around 600 A.D., with most dating to after 1,000 A.D. but before the Spanish conquest.
"We date the spheres by pottery styles and radiocarbon dates associated with archeological deposits found with the stone spheres," Hoopes said. "One of the problems with this methodology is that it tells you the latest use of the sphere but it doesn't tell you when it was made. These objects can be used for centuries and are still sitting where they are after a thousand years. So it's very difficult to say exactly when they were made."
Speculation and pseudoscience have plagued general understanding of the stone spheres. For instance, publications have claimed that the balls are associated with the "lost" continent of Atlantis. Others have asserted that the balls are navigational aids or relics related to Stonehenge or the massive heads on Easter Island.
"Myths are really based on a lot of very rampant speculation about imaginary ancient civilizations or visits from extraterrestrials," Hoopes said.
In reality, archaeological excavations in the 1940s found the stone balls to be linked with pottery and materials typical of pre-Columbian cultures of southern Costa Rica.
"We really don't know why they were made," Hoopes said. "The people who made them didn't leave any written records. We're left to archeological data to try to reconstruct the context. The culture of the people who made them became extinct shortly after the Spanish conquest. So, there are no myths or legends or other stories that are told by the indigenous people of Costa Rica about why they made these spheres."
Hoopes has a created a popular Web page to knock down some of the misconceptions about the spheres. He said the stones' creation, while vague, certainly had nothing to do with lost cities or space ships.
"We think the main technique that was used was pecking and grinding and hammering with stones," said Hoopes. "There are some spheres that have been found that still have the marks of the blows on them from hammer stones. We think that that's how they were formed, by hammering on big rocks and sculpting them into a spherical shape."
Tuesday, March 23, 2010 | 0 Comments
Students discover new species of raptor dinosaur
The two PhD students, Michael Pittman from UCL (University College London) and Jonah Choiniere from George Washington University (GWU), found the dinosaur sticking out of a cliff face during a field project in Inner Mongolia, China. Their research is published online today in the journal Zootaxa.
"Jonah saw a claw protruding from the cliff face. He carefully removed it and handed it to me. We went through its features silently but he wanted my identification first. I told him it was from a carnivorous dinosaur and when he agreed I'm surprised nobody in London heard us shouting," said Michael Pittman, a PhD student in the UCL Department of Earth Sciences who was the co-discoverer of the dinosaur.
"I've always wanted to discover a dinosaur since I was a kid, and I've never given up on the idea. It was amazing that my first discovery was from a Velociraptor relative. My thesis is on the evolution and biomechanics of dinosaur tails but the carnivorous dinosaurs are my favourite and my specialty," he added.
At approximately 2.5 metres long and 25 kilograms, the researchers believe Linheraptor would have been a fast, agile predator that preyed on small horned dinosaurs related to Triceratops. Like other dromaeosaurids, it possessed a large "killing claw" on the foot, which may have been used to capture prey. Within the Dromaeosauridae family, Linheraptor is most closely related to another recently discovered species Tsaagan mangas.
Linheraptor differs from all other dromaeosaurs because of a triangular hole in front of the eye socket called the antorbital fenestra, which is a space in the skull that sinuses would have occupied. In Linheraptor this triangular hole is divided into two cavities – one of which is particularly big.
"This is a really beautiful fossil and it documents a transitional stage in dromaeosaurid evolution," said Dr. Xu Xing, Professor of Palaeontology at the Institute of Vertebrate Paleontology & Paleoanthropology (IVPP).
Linheraptor was found in rocks of the Wulansuhai Formation, part of a group of red sandstone rocks found in Inner Mongolia, China during a field expedition by the researchers in 2008. It is the fifth dromaeosaurid discovered in these rocks, which are famous for their preservation of uncrushed, complete skeletons.
The research was done as part of the Inner Mongolia Research project, led by Dr. Xu, which aims to better understand the Late Cretaceous ecosystem of Inner Mongolia, China which is analogous but less well-studied than the well known Late Cretaceous ecosytem of Outer Mongolia. The research was funded by the Geological Society of London, the US National Science Foundation, the Chinese National Science Foundation, and George Washington University.
Friday, March 19, 2010 | 0 Comments
A blue mystery
The answer: seeking an uncontaminated sample of a mineral that might have been the key ingredient in the blue used to decorate "blue painted pottery" popular among the Egyptian elite during the New Kingdom (1550 to 1079 BCE).
Colleague Colin A. Hope, an expert in blue painted pottery, had asked if she wouldn't help him pin down the source of the blue pigment by sampling and analyzing material fromt he mine.
Hope and Smith, together with Paul Kucera, a doctoral student at Monash University who first identified the mines, describe the pottery, the mines and the mineral in a chapter of Beyond the Horizon, a festschrift for the Egyptologist Barry A. Kemp
'Generic geologist'
In the wastes of the eastern Sahara, nestled against the limestone escarpment that separates the desert from the Nile Valley, lies the Dakhleh Oasis. This fortunate spot, where deep water is able to reach the surface along fractures and faults under its own pressure, has been continuously inhabited for a very long time — perhaps as long as 400,000 years.
During that period there were roughly four glacial cycles and, although Egypt itself was ice-free, the local climate oscillated from hyperarid to semi-arid as the Earth's orbital position drove changes in the location of the tropical rainfall belts.
Smith studies the impact of these climate fluctuations on ancient oasis dwellers.
But Smith is also the "generic geologist" as she puts it, for the Dakhleh Oasis Project, a long-term study of the oasis that covers the entire stretch of Dakhleh history, from the Neolithic through the Pharaonic, Roman, Islamic and modern settlements, and employs — off and on — more than 50 specialists.
"The dig house is open from November until March," Smith says.
As generic geologist, Smith was asked to help with a material-sourcing puzzle that she says was "way outside her period." During the 2007 season, Colin A. Hope, PhD, associate professor and director of the Center for Archaeology and Ancient History at Monash University in Australia, asked her whether a mineral found at the oasis could have been used to color the blue painted pottery.
It was a small question but an intriguing one.
Blue painted pottery
Most Egyptian pottery is undecorated, but during the New Kingdom, the period when Egypt is at the zenith of its power, a variety of pottery was elegantly decorated in a distinctive pale blue.
The pottery has been found at many sites in Egypt, and also in the Middle East and in Sudan.
The largest deposits, however, were found at New Kingdom sites in Egypt, including Malqata (the palace complex of Amenhotep III), Amarna (the remains of the city built by the Akenaten, the famous pharaoh who moved the capital from Thebes and established his own religion), the cemetary at Deir el-Medineh (the village where artisans who worked on the tombs in the Valley of the Kings during the New Kingdom lived), and the Great Temple of Amun (patron of kingship during the New Kingdom).
"Walking over some sites, it is only a matter of minutes before several shards of blue painted pottery or cobalt blue glass or faience can be collected," Hope, who has written extensively about the pottery, says.
Given the restricted use to which the pigment was put and the archeological sites where remnants were found, Hope believes it was probably available only to artisans associated with major royal residences.
The pale blue is distinguishable at a glance from the brilliant blues and blue-greens of the faience glazes common from the 3000 BC onward. Faience, probably most familiar in the form of the small statue of a hippo nicknamed William that is now in the collection of the Metropolitan Museum of Art in New York, was made by adding ground copper to ground quartz to create what ceramists today call Egyptian paste.
But it is difficult to create durable patterns with copper pigment on pottery, says Hope. "Copper-based pigments must be applied in thick layers and were added after firing, so they tended to flake off when an object was handled. Instead of copper, the colorant used on most of the blue painted pottery is cobalt, which was fired onto the pots.
Where did the cobalt-bearing mineral come from? Analysis of the paint showed that the cobalt was accompanied by trace amounts of zinc, nickel and manganese, a mixture of elements distinctive enough to serve as a chemical fingerprint.
The mines of Dakhleh
At the height of its power, the Egyptian administration of the Nile Valley sponsored mineral exploitation of the Valley and surrounding desert regions. As early as 1980, it was suggested that the cobalt might have come from the desert oases at Dakhleh and Kharga.
In the lower foothills of the oasis escarpment at the western end of Dakhleh, four mine shafts were meticulously hand-cut into the rock. Steps carved along the shafts allowed a safe descent. The shafts provided access to horizontal galleries, some as long as 15 meters, that followed horizontal veins of the mineral alum.
A few centimeters thick, the alum veins are fibrous, pale gray to pink in color and slightly astringent.
Alum is both the term for a specific compound and for a class of compounds, all of which contain two negatively charged sulfate groups and two chemical elements or groups bearing a positive charge. The specific compound is hydrated aluminum potassium sulfate but many other elements or groups can substitute for the aluminum and potassium, and cobalt is one of these.
Alum was probably exploited for a variety of purposes in ancient times, some having nothing to do with color. The Egyptians, for example, used alum both to whiten skins during tanning and to prepare cloth to absorb dye.
Alum is still used today in styptic pencils to stem bleeding and in recipes for pickling cucumbers. More recently, it has been in vogue as a "crystal deodorant" that is sold as more natural than older deodorant products.
Was the Dakhleh Oasis alum used as a general-purpose astringent, or did it have the same chemical fingerprint as the blue paint on the pottery?
Analyzing the alum
To find out, Smith needed to sample the alum and analyze its composition.
"I wanted to get relatively unaltered samples," she says, "which is why I was crawling to the end of a gallery. The galleries were small enough you couldn't really crawl on your hand and knees: you had to belly crawl."
Smith brought the samples she collected back to Washington University where she ran them through a variety of sophisticated analytical instruments. "When we characterize a natural mineral," she says, "we want to know two things: its chemical composition and then how the elements that make it up are arranged, or its crystal structure."
In the case of the Dakhleh alum, the crystal structure was of little use because it would have been destroyed in preparing the paint. Only the composition could connect the alum to the pottery.
Smith's results showed that the alum did contain cobalt, although they weren't particularly rich in this element. The cobalt, however, was accompanied by trace amounts of manganese, nickel and zinc, the same mixture of elements found in the blue paint.
Surprised by the low concentration of cobalt, Smith wondered if the ancient artisans hadn't found a way to concentrate it on site. One sample she collected, a crust at the edge of a partially flooded mine shaft, had a higher cobalt content than the others. Because sulphate dissolves easily and the mines were much more likely to have been flooded in the past, she wondered whether the cobalt was mined not by chipping it out of the rock but instead by ladling water out of the mines and collecting the sediment left over when the water evaporated.
"But this is wild arm waving given the amount of data," Smith says.
This small exercise in archeological problem solving left her with a deep respect for the long-vanished miners.
"I look at all these different veins of sulfate and I don't know which are useful for which purposes without doing analyses, but they must have had ways of telling from observable properties which ones to mine. That's impressive," she says.
Thursday, March 18, 2010 | 0 Comments
3,400-Year-Old Statues Unearthed in Egypt
Wednesday, March 17, 2010 | 0 Comments
Rare armor-plated creature discovered in Canada's capital
It was Rudkin who first recognised its scientific significance: "This nifty little specimen first came to my notice when I received a letter from an amateur fossil collector in Nepean, Ontario. In prospecting for fossils in rock from a temporary building excavation he had turned up a small block containing a complete trilobite, but next to it was something else and he sent me a slightly fuzzy but very intriguing photo. The mystery fossil was clearly not another trilobite, and I although couldn't be certain, I thought it might be some sort of annelid worm with broad, flattened scales. James, the collector, generously agreed to lend me the specimen and I realised immediately it was a complete, fully articulated machaeridian! The first I had ever seen."
At that time it was not known that machaeridians were annelids. "James was happy to donate the specimen to the Royal Ontario Museum, in exchange for a promise that I'd someday publish his discovery."
It was not until 2008 that Rudkin's hunch was confirmed, when a team of palaeontologists, including Jakob Vinther, decribed new machaeridian fossils from remote mountain localities in Morocco, revealing their relationship to annelid worms. Rudkin and Vinther agreed to work together to interpret the Ottawa specimen, and it is the results of that collaboration that are published in the current Palaeontology.
Plumulitid machaeridians look like modern bristleworms, with stout walking limbs bearing long bundles of bristles, but on their back they carried a set of mineralized plates. According to Vinther, "the plates themselves were rigid, but they could move relative to one other, providing plumulitids with a protective body armour very similar to the flexible metal armour invented by humans 450 million years later. Machaeridian body armour is unique among annelids, and probably helped them to succeed as ubiquitous components of marine ecosystems for more than 200 million years."
With the publication of this paper Rudkin is finally able to make good on his promise "It's great to be able to acknowledge the collector", says Rudkin, but there is a twist to this tale: the man who found the specimen has now gone missing. "Regrettably, I lost contact with James and numerous enquiries as to his whereabouts have come up empty. I hope he somehow gets wind of all this."
Wednesday, March 17, 2010 | 0 Comments
Pottery leads to discovery of peace-seeking women in American Southwest
Salado pottery dates from the 13th to 15th centuries in which there was major political and cultural conflict in the American Southwest. Brutal executions and possible cannibalism forced thousands of people to abandon their native regions and move to areas of Arizona and New Mexico. Another source of conflict appeared after the female refugees and their children arrived in their new homelands.
"Conflict was defused through the direct action of women who sought to decrease the tensions that threatened to destroy their communities," VanPool said. "The rise of the Salado tradition allowed threatened communities to stabilize over much of modern-day Arizona and new Mexico, altering the course of Southwestern prehistory. Given that the Salado system lasted from 1275 to around 1450, it was most certainly successful."
Friday, March 12, 2010 | 0 Comments
Australian archaeologists uncover 40,000-year-old site
The find came during an archaeological survey ahead of roadworks near Tasmania's Derwent River and soil dating had established the age of the artefacts found there.
"When the archaeological report came out it showed that (life there) had gone back longer than any other recorded place anywhere else in Tasmania, dating back to 40,000 years," Mansell told AFP.
Up to three million artefacts, including stone tools, shellfish fragments and food scraps, were believed to be buried in the area, which appeared to have been a meeting ground for three local tribes.
They died out after white settlers arrived in the late 18th century.
"They (settlers) hunted people here to this place and shot them just so they could get the land," said Mansell. "Many others were imprisoned until they died."
"In terms of culture and history this region now represents Tasmania's Valley of the Kings," he added, referring to the world heritage listed Egyptian tombs on the west bank of the Nile.
"When you get something like this that evokes memory of what your people did before we were born and evokes a memory about the legacy that they left us ... it makes the place irreplaceable."
The survey was finished last week and chief archaeologist Rob Paton said he had been surprised at the age of the items found.
"We haven't even done a reading on the bottom sample yet, I was expecting 17,000 (years) for the base of the trench and about 4 or 5,000 (years) for the top," Paton told state radio.
Paton said luminescence readings -- measuring the age of the artefacts based on how much exposure they had received to sunlight -- had been "nice and statistically tight".
"That suggests to me that they're probably correct, giving us a top reading of 28,000 (years old) and certainly seeming to go back another 10,000 (years) at least beyond that," he said.
The readings indicated that "we do have the oldest, most southern site anywhere in the world", said Paton, making it "an important site for anyone and quite exciting for us".
"I think the thing to stress is no matter what the age of the site it's important anyway," he added.
Mansell said the tribes were famous for their defiant stand against the settlers, and so frustrated the authorities they ultimately issued an order that any Aborigine in the area be shot on sight.
He said the dig's findings were merely the "tip of the iceberg" and called for plans to build a bridge over the site to be scrapped.
"The Tasmanian government must immediately declare it a protected site, not just for Aboriginal people but for peoples of the world," said Mansell.
Australia's original inhabitants, with cultures stretching back tens of thousands of years, are believed to have numbered around one million at the time of white settlement.
Thursday, March 11, 2010 | 0 Comments
Half of Earth's life may lie below land, sea
"Earth's habitable zone extends to depths of hundreds or thousands of meters," Katrina Edwards, a microbiologist at the University of Southern California, told a December conference of the American Geophysical Union in San Francisco. "The organisms that live in this environment may collectively have a mass equivalent to that of all of Earth's surface dwellers and may provide keys to solving major environmental, agricultural and industrial problems."
For example, geologists are considering whether to store some of the world's excess carbon dioxide, a major greenhouse gas, in a worldwide network of crevices below the seafloor.
Scientists say research on "intraterrestrial life" complements astronomers' hunt for "extraterrestrial life" around other stars and planets. The search for E.T. starts at home.
"Much that we do in our work to discover and understand the deep biosphere has relevance to the origin and search for life elsewhere in the universe," Edwards said by e-mail. "Fundamentally, this is all about life detection. ... Our inner space is a natural testing ground for outer space."
To advance their understanding of subsurface life, marine geologists are about to launch three drill ship expeditions to punch holes in the seafloor and implant long-term scientific "observatories" linked by cable and satellite to onshore laboratories.
"We'll be sitting in front of a fire hose of data," said Andrew Fisher, a geophysicist at the University of California in Santa Cruz.
Dyed fluids will be pumped into selected places so scientists can follow the flow of water and microbes through a maze of subsurface "plumbing." These deep oceanic aquifers are thought to contain as much water as all the rivers on Earth.
"It'll be like determining how your home plumbing works by sampling the water at the taps," Fisher said.
Subsurface biosphere research may shed light on the origin of life on Earth and the possibility of life on other planets.
"The conditions we see in the sub-seafloor are similar to what conditions may have been on the early Earth," Fisher said. Similar conditions may exist or have existed on Mars or the moons of Jupiter.
"It is highly likely that if Mars supports life, it will also be in a deep biosphere where temperatures are high enough to allow liquid water," John Parnell, a geologist at the University of Aberdeen, Scotland, told a conference of planetary scientists last week in The Woodlands, Texas.
Steven D'Hondt, an oceanographer at the University of Rhode Island, will lead the expedition to the South Pacific Gyre. The JOIDES Resolution will drive seven holes in the seafloor to study microbial life there.
One objective will be to determine whether deep sea chemicals, such as hydrogen and sulfur, that don't depend on energy from the sun on Earth's surface can nourish subsurface microbes.
Wednesday, March 10, 2010 | 0 Comments
Khirbet Qeiyafa identified as biblical 'Neta'im'
American scholar Prof. William Albright, a leading archaeologist, proposed associating Neta'im with Khirbet En-Nuweiti', which is also located near the Elah Valley, based on the phonological similarity between the two names. Archaeological surveys at Khirbet En-Nuweiti', however, revealed that it was only inhabited during Hellenistic and Roman-Byzantine times, and not during the Iron Age.
Prof. Galil's identification of Khirbet Qeiyafa with Neta'im is based on the proximity of Khirbet Qeiyafa to biblical Gederah/Khirbet Ğudraya; on the archaeological findings – including impressive fortifications - dating from the time of King David's rule and indicating that this was an administrative center; and on the preserved name of nearby Khirbet En-Nuweiti'.
"The archeological findings at this site, the discovery of the earliest and most important Hebrew inscription to be found to date, and the understanding, based on the biblical text, that members of the Tribe of Judah inhabited the town and worked in the king's service, testify to Khirbet Qeiyafa – Neta'im – being an important administrative center in the border region of the Kingdom of Israel during the time of King David's reign. The existence of this fortified administrative center relatively far from the center of the kingdom testifies to a conflict that broke out between the Israelites the Philistines after David was victorious over the House of Saul and all of the Tribes of Israel were unified under his leadership. It is further proof of a large and powerful kingdom during the days of King David," Prof. Galil concludes.
Tuesday, March 09, 2010 | 0 Comments
Utah paleontologist part of international team to discover oldest known dinosaur relative
Fossil bones of at least 14 individuals were recovered from a single bone bed in southern Tanzania making it possible to reconstruct nearly the entire skeleton, except portions of the skull and hand. The individuals stood about 1.5 to 3 feet (0.5 to 1 meter) tall at the hips and were 3 to 10 feet (1 to 3 meters) long. They weighed about 22 to 66 pounds (10 to 30 kilograms), walked on four legs, and most likely ate plants or a combination of plants and meat.
"The crazy thing about this new dinosaur discovery is that it is so very different from what we all were expecting, especially the fact that it is herbivorous and walked on four legs, said Irmis, who was involved in the researching the discovery over the past three years.
Asilisaurus kongwe is part of a newly recognized group known as silesaurs. "We knew that there were a number of species from the Triassic that were similar to Asilisaurus," said Irmis, "but we were only able to recognize that they formed this group called silesaurs with the new anatomical information from Asilisaurus." Members of the silesaur group were distributed across the globe during the Triassic, when all of the continents were together in a supercontinent called Pangaea.
Silesaurs are the closest relatives of dinosaurs, analogous to the close relationship of humans and chimps. Even though the oldest dinosaurs discovered so far are only 230 million years old, the presence of their closest relatives 10 million to 15 million years earlier implies that silesaurs and the dinosaur lineage had already diverged from a common ancestor by 245 million years ago. Silesaurs continued to live side by side with early dinosaurs throughout much of the Triassic Period (between about 250 million and 200 million years ago). The researchers conclude that other relatives of dinosaurs, such as pterosaurs (flying reptiles) and small forms called lagerpetids, might have also originated much earlier than previously thought.
Silesaurs have triangular teeth and a lower jaw with a beak-like tip, suggesting that they were specialized for an omnivorous and/or herbivorous diet. These same traits evolved independently in at least two dinosaur lineages (ornithischians and sauropodomorphs). In all three cases, the features evolved in animals that were originally meat-eaters. Although difficult to prove, it's possible that this shift conferred an evolutionary advantage. The researchers conclude that the ability to shift diets may have lead to the evolutionary success of these groups.
"The research suggests that at least three times in the evolution of dinosaurs and their closest relatives, meat-eating animals evolved into animals with diets that included plants," said Irmis. "These shifts all occurred in less than 10 million years, a relatively short time by geological standards, so we think that the lineage leading to silesaurs and dinosaurs might have had a greater flexibility in diet, and that this could be a reason for their success."
This new species (Asilisaurus) is found along with a number of primitive crocodilian relatives in the same fossil beds in southern Tanzania. The presence of these animals together at the same time and place suggests that the diversification of the relatives of crocodilians and dinosaurs was rapid, and happened earlier than previously suggested. It sheds light on a group of animals that later came to dominate terrestrial ecosystems throughout the Mesozoic Era (250 million to 65 million years ago).
"This new research suggests that there are more groups of animals yet to be discovered in this early period of dinosaur relatives," said Irmis. "It's very exciting because the more we learn about the Triassic Period, the more we learn about the origin of the dinosaurs and other groups."
Monday, March 08, 2010 | 0 Comments
30 years later, what killed the dinosaurs is revisited
In that year, father and son researchers Luis and Walter Alvarez first proposed the notion that an asteroid impact killed off the dinosaurs. They had discovered that high levels of iridium, an element rare on Earth but common on extraterrestrial objects like meteors, were uniformly present in sedimentary samples that could be dated back to the extinction event, which marked the transition between two geologic periods.
At the time, they did not know where on Earth that impact might have taken place. It would be another 11 years before researchers Alan Hildebrand and Glen Penfield suggested that a crater left behind by an asteroid impact was buried on the Yucatan peninsula. With the crater nearly 200 kilometers (125 miles) in diameter, the impact was one large enough to have caused the mass extinction in agreement with the Alvarez hypothesis.
The force of the impact itself — there is evidence of giant earthquakes and tsunami waves more than 1,000 feet tall being generated in the immediate aftermath — and the following profound atmospheric changes combined to make the planet uninhabitable for between 40 and 70 percent of all life forms on Earth.
But rival explanations, though outside the mainstream, have continued to proliferate in high-profile fashion. One theory that has gained widespread attention attributes the mass extinction to a volcanic event in India that took place at roughly the same time as the impact. Another faction of researchers acknowledges that the asteroid did strike but that its effects were not enough to cause the mass extinction.
Norris notes that an inspection of ancient layers of seafloor sediment around the world show a clear record of the event contained in a red or green band composed of materials ejected from the blast. These include pieces of rock like those on the Yucatan, glassy droplets that represent melted rock, microscopic diamonds made under the very high pressures produced by the impact and meteoric debris.
"There are also monster submarine landslides along the entire East Coast of the U.S. from the massive earthquake triggered by the impact," he said.
Norris points to several pieces of evidence from the deep sea that support a tight link between the impact and the mass extinction. In most places in the deep ocean, the impact debris layer is associated with an abrupt decrease in the size of fossils — the appearance of a dwarfed "disaster" fauna. Abrupt environmental changes throughout history such as the impact tend to favor smaller organisms that have more rapid lifecycles and fewer resource needs than larger organisms. Biological productivity plummets in many parts of the oceans immediately after the impact. The drop in productivity is partly reflected by a change in the color of deep-sea sediments — from creamy white to brown or grey — as light-colored fossil shells abruptly decreased in number.
Individually, the decrease in fossil size, the appearance of a "disaster fauna" and the plummet in ocean productivity are unusual, and together with an impact debris layer, are unique in the deep-sea sediment record.
"This is not a 'smoking gun,'" said Norris, "it's a 'smoking cannon.'"
Friday, March 05, 2010 | 0 Comments
Dinosaurs might be older than previously thought
Asilisaurus is part of a sister group to dinosaurs known as silesaurs. Silesaurs are considered dinosaur-like because they share many dinosaur characteristics but still lack key characteristics all dinosaurs share. The relationship between silesaurs and dinosaurs is analogous to the close relationship of humans and chimps. Even though the oldest dinosaurs discovered so far are only 230 million years old, the presence of their closest relatives 10 million years earlier implies that silesaurs and the dinosaur lineage had already diverged from common ancestors by 240 million years ago. Silesaurs continued to live side by side with early dinosaurs throughout much of the Triassic Period (between about 250 and 200 million years ago).
This is the first dinosaur-like animal recovered by archaeologists from the Triassic Period in Africa.
Fossil bones of at least 14 individuals were recovered from a single bone bed in southern Tanzania making it possible to reconstruct a nearly entire skeleton, except portions of the skull and hand. The individuals stood about 0.5 to 1 meter (1.5 to 3 feet) tall at the hips and were 1 to 3 meters (3 to 10 feet) long. They weighed about 10 to 30 kilograms (22 to 66 pounds). Asilisaurus walked on four legs and most likely ate plants or a combination of plants and meat. They lived about 240 million years ago.
Silesaurs have triangular teeth and a lower jaw with a beak like tip which suggest that they were specialized for an omnivorous and/or herbivorous diet. These same traits evolved independently in at least two dinosaur lineages. In all three cases, the features evolved in animals that were originally meat-eaters. Although difficult to prove, it's possible that this shift conferred an evolutionary advantage. An ecosystem can support far more plant eaters than meat eaters. So being able to eat plants might have opened up a broader range of habitats. Not counting modern birds, dinosaurs survived for about 180 million years.
This new species is found along with a number of primitive crocodilian relatives in the same fossil bed in southern Tanzania. The presence of these animals together at the same time and place suggests that the diversification of the relatives of crocodilians and birds was rapid and happened earlier than previously suggested. It sheds light on a group of animals that later came to dominate the terrestrial ecosystem throughout the Mesozoic (250 to 65 million years ago).
"Everyone loves dinosaurs," said Nesbitt. "But this new evidence suggests that they were really only one of several large and distinct groups of animals that exploded in diversity in the Triassic, including silesaurs, pterosaurs, and several groups of crocodilian relatives."
Silesaurus, the first known member of the silesaur group was discovered in 2003. In just 7 short years, specimens of 8 other members have been unearthed from Triassic rocks across the globe.
"This goes to show that there are whole groups of animals out there that we've never even found evidence of that were very abundant during the Triassic," said Nesbitt. "It's exciting because it means there is still so much chance for discovery."
The name Asilisaurus kongwe is derived from asili (Swahili for ancestor or foundation), sauros (Greek for lizard), and kongwe (Swahili for ancient).
Thursday, March 04, 2010 | 0 Comments
Recently analyzed fossil was not human ancestor as claimed, anthropologists say
"Many lines of evidence indicate that Darwinius has nothing at all to do with human evolution," says Chris Kirk, associate professor of anthropology at The University of Texas at Austin. "Every year, scientists describe new fossils that contribute to our understanding of primate evolution. What's amazing about Darwinius is, despite the fact that it's nearly complete, it tells us very little that we didn't already know from fossils of closely related species."
His co-authors are anthropologists Blythe Williams and Richard Kay of Duke and evolutionary biologist Callum Ross of the University of Chicago. Williams, Kay and Kirk also collaborated on a related article about to be published in the Proceedings of the National Academy of Sciences that reviews the early fossil record and anatomical features of anthropoids – the primate group that includes monkeys, apes, and humans.
Last spring's much-publicized article on Darwinius was released in conjunction with a book, a History Channel documentary, and an exhibit in the American Museum of Natural History. At a news conference attended by New York Mayor Michael Bloomberg, the authors unveiled the nearly complete fossil of a nine-month-old female primate that had been found at the site of Messel in Germany.
But other anthropologists were immediately skeptical of the conclusions and began writing the responses that are being published this month.
"Just because it's a complete and well-preserved fossil doesn't mean it's going to overthrow all our ideas," says Williams, the lead author. "There's this enormous body of literature that has built up over the years. The Darwinius research completely ignored that body of literature."
That literature centers on the evolution of primates, which include haplorhines (apes, monkeys, humans, tarsiers) and strepsirrhines (lemurs, lorises). The two groups split from each other nearly 70 million years ago.
The fossil group to which Darwinius belongs – the adapiforms – have been known since the early 1800s and includes dozens of primate species represented by thousands of fossils recovered in North America, Europe, Asia and Africa. Some adapiforms, like North American Notharctus, are known from nearly complete skeletons like that of Darwinius. Most analyses of primate evolution over the past two decades have concluded that adapiforms are strepsirrhines, and not direct ancestors of modern humans.
The most recent such analysis, published last year in the journal Nature, concluded that Darwinius is an early strepsirrhine and a close relative of the 39-million-year- old primate Mahgarita stevensi from West Texas.
Nevertheless, the scientists who last year formally described Darwinius concluded that it was an early haplorhine, and even suggested that Darwinius and other adapiform fossils "could represent a stem group from which later anthropoid primates evolved."
For example, they note that Darwinius has a short snout and a deep jaw – two features that are found in monkeys, apes, and humans.
However, Kirk, Williams and their colleagues point out that short snouts and deep jaws are known to have evolved multiple times among primates, including several times within the lemur/loris lineage. They further argue that Darwinius lacks most of the key anatomical features that could demonstrate a close evolutionary relationship with living haplorhines (apes, monkeys, humans, and tarsiers).
For instance, haplorhines have a middle ear with two chambers and a plate of bone that shields the eyes from the chewing muscles.
"There is no evidence that Darwinius shared these features with living haplorhines," says Kirk. "And if you can't even make that case, you can forget about Darwinius being a close relative of humans or other anthropoids."
Wednesday, March 03, 2010 | 0 Comments
'Anaconda' meets 'Jurassic Park': Study shows ancient snakes ate dinosaur babies
The fossils were first found in 1987 by dinosaur egg expert Dhananjay Mohabey from the Geological Survey of India, in rocks of the Lameta Formation in Gujarat, a state in western India known for its rich fossil record of dinosaurs and their eggs. Originally identified as a hatchling dinosaur, the fossils were recognized to include a snake by dinosaur paleontologist Jeff Wilson from the University of Michigan and Mohabey in 2001.
"I saw the characteristic vertebrae of a snake beside the dinosaur eggshell and larger bones, and I knew it was an extraordinary specimen ... even if I couldn't put the whole story together at that point. I just knew we needed to examine it further," said Wilson. They invited snake specialist Head and geologist Shanan Peters from the University of Wisconsin-Madison, to collaborate on the study of the fossils, including field and lab work in India, the U.S.A., and Canada.
Sanajeh indicus, which means "ancient gape from India", is represented by a nearly complete skull and lower jaws along with vertebrae and ribs coiled around a crushed titanosaur egg, next to the remains of a 0.5-metre-long titanosaur hatchling. These dinosaurs, part of a larger group called sauropods, were long-necked, four-legged plant-eaters that grew to weigh up to 100 tonnes, and Wilson says they likely grew quickly in their first year, beyond the reach of predators like Sanajeh.
The findings—along with two other similar snake-egg pairings, suggest that snakes fed on titanosaur hatchlings when they emerged from their eggs. "The eggs were laid in loose sands and covered by a thin layer of sediment. We think that the hatchling had just exited its egg, and its movement attracted the snake," explains Mohabey. "It would have been a smorgasbord," says Head. "Hundreds or thousands of defenseless baby sauropods could have supported an ecosystem of predators during the hatching season."
The remains capture a moment in Cretaceous time. "Burial was rapid and deep," says Peters. "Probably a pulse of slushy sand and mud released during a storm caught them in the act."
Tuesday, March 02, 2010 | 0 Comments