Paleontology news

The outline of an ancient Roman city buried beneath cropland near Venice, Italy, has been mapped in detail for the first time with the aid of aerial photography, a new study says.

In its heyday, the city was fronted by what is now known as the Laguna Veneta, and a "brackish smell" likely filled the air, noted study co-author Paolo Mozzi, a geomorphologist at the University of Padua in Italy.

"You can expect a lot of coming and going, a lot of ships arriving through the lagoon from points in the Adriatic, [and] there were merchants running along the Via Annia," a road that crossed the city, Mozzi said.

Summer was hot and muggy, while winter days were often shrouded in fog.

The findings paint a picture of a sophisticated community with the know-how to thrive in a lagoon environment centuries before Venice and its famous canals emerged, the study authors conclude.

Crop Survey

Today the remains of Altinum lie under fields of maize and soy on the Italian mainland.

For their map, described this week in the journal Science, Mozzi and colleagues took advantage of drought conditions in 2007 to take photographs of the fields in visible and near-infrared light.

Plants growing on top of stone structures such as walls and building foundations suffer greater water stress than plants over canals filled in with sediment, Mozzi explained.

"If you look at it from the air, you see the geometry of these plants, which show underground the geometry of the structure."

Modern-day Venice sits on islands in the Laguna Veneta, which is separated by barrier islands from the Adriatic Sea.

Although it's miles away from Altinum, the study authors consider the mainland city to have been an ancestor of Venice.

Scholars believe that Altinum's residents fled their home during barbarian invasions in the fifth to seventh centuries A.D. and colonized the northern lagoon islands.

Records show, for example, that Altinum's bishop left for the island of Torcello in A.D. 639.

A few centuries later, Venice emerged from the dispersed islands in the central lagoon.

"Our point on the connection between Altinum and Venice is the movement of these people from the mainland out to living in the islands," Mozzi said.

"How can they do that? Because they were already very adapted to the lagoon," which became a safe refuge from less water-savvy attackers.

Venice Ancestor

Experts not affiliated with the research agreed that the new map of Altinum is a tremendous advance for understanding the little-known city.

For instance, the survey offers firm evidence that Altinum was a classic Roman port similar to the nearby ancient cities of Ravenna and Aquileia.

However, several experts emphasized that the city's link to Venice is complex.

Rupert Housley, a geographer at Royal Holloway, University of London, is studying how Venice took root at the heart of a lagoon.

The aerial photography alone can't back up the notion that Altinum was particularly well adapted to lagoon living, Housley said.

"Certainly the residents of Altinum may well have contributed to peopling of the islands, probably along with the other coastal towns," he commented via email.

But from the map there appears to be nothing especially unique about Altinum compared with other nearby Roman ports, he noted.

Albert Ammerman, an archaeologist at Colgate University in Hamilton, New York, said Venice arose organically from migrating residents of several coastal cities, including Altinum.

All of those cities' people, he said, "knew how to live in this aquatic environment. They had all the skills and local knowledge, so it wasn't very difficult for them to go out there" and survive.

credited to news.nationalgeographic.com

The mode of reproduction seen in modern sharks is nearly 400 million years old. That is the conclusion drawn by Professor Per Erik Ahlberg, Uppsala University, from his discovery of a so-called "clasper" in a primitive fossil fish earlier this year. The research results are published today in Nature. In February this year, a paper published in Nature by a team of Australian and British researchers showed that placoderms, a group of ancient fishes that died out more than 350 million years ago, gave birth to live young. Beautifully preserved fossil embryos in the body cavity of the placoderm Incisoscutum showed that these fishes, close to the common origin of all jawed vertebrates, had a mode of reproduction similar to modern sharks. Live birth requires internal fertilisation; sharks achieve this by using a "clasper", an extension of the pelvic fin that functions like a penis. The authors looked for a clasper in their placoderm fossils but couldn't find one, so they were forced to argue that it had been made of soft cartilage and had not been preserved.

Shortly afterwards, Per Erik Ahlberg from Uppsala University visited one of the Australian researchers and spotted a perfectly preserved bony clasper in one of their Incisoscutum fossils.

"It was lying in plain view but had been misinterpreted as part of the pelvis and overlooked," he says.

Together with the original authors he is publishing a short paper in this week's Nature that presents this missing piece of the puzzle and completes the picture of placoderm reproduction from mating to birth.

"It provides a pedigree of nearly 400 million years for the "advanced" and seemingly specialised reproductive biology of modern sharks," says Per Ahlberg.

credited to esciencenews.com

After nearly 30 years in the field, archaeologist Leonardo López Luján may be on the verge of the discovery of a lifetime: the only known tomb of an Aztec king.

The animal was found wearing wooden earflaps mounted with turquoise mosaic, a collar of greenstone beads, and golden bells around its four feet.

But López Luján, a senior researcher at the Templo Mayor Museum in Mexico City, remains cool and cautious.

The skeleton could be that of a dog or a Mexican wolf—a question López Luján's team hopes to clear up with DNA testing.

"It would be very important if it turns out to be a dog, as it would tell us that we are close to arriving at a funeral context," he said.

The skeleton "could represent the dog that accompanied the deceased to the other side and helped them to cross a river called Chicnahuapan, one of the dangers before arriving at the ninth and deepest level of the underworld," López Luján said.

Many ancient Mesoamerican cultures, including the Aztec, believed that dogs escorted their masters to the afterlife, he added, and archaeologists have discovered many dog skeletons alongside Mesoamerican human remains.

Unlooted Tomb?

The Templo Mayor canine skeleton was found next to a stone box that contained the remains of a golden eagle, flint sacrificial knives, crustacean shells, and balls of copal resin—tree sap thought to have been used in various substances, such as incense, medicine, and glue.

Recent excavations also uncovered unbroken plaster seals made of lime and sand.

The existence of multiple seals suggests that the tomb, if it's there, could be a collective crypt containing the king and his successors, López Luján said. "Each time they buried a newly deceased [dignitary], they sealed the entrance with a plaster seal," he speculated.

That the seals are unbroken suggests that the potential tomb has not been looted.

If there is a royal tomb behind the seals, López Luján would expect to find the ruler's ashes in stone or ceramic containers as well as the remains of servants, accompanied by personal objects and more offerings from the funeral rites.

The tomb, López Luján says, would not be as large as that of Tutankhamun in Egypt or the Maya funeral chambers of Copán in Honduras, "because the Mexicas [Aztecs] never build arches or vaults. It might be a very small room full of offerings."

Slow Going

Despite rising expectations, the archaeologist said he and his team must be patient.

Only by working slowly and methodically will the team be able to reconstruct the funerary customs and other artifacts that could shed light on the Aztec economy, political system, and religion as it existed before the arrival of the Spanish in the 1500s.

And now the workers must grapple with yet more challenges: the weather and a high water table.

"We have to go very slow," he said, "because now we are in the rainy season."

credited to news.nationalgeographic.com

An ancient fossil crocodile coated in armadillo-like body armor was unveiled yesterday at an environmental museum in Brazil. Dubbed Armadillosuchus arrudai, the newly described species of crocodile roamed the arid interior of Brazil about 90 million years ago, during the late Cretaceous period, scientists said.

Body armor has never been "found in any other fossil or living crocodile species," Ismar de Souza Carvalho, a paleontologist at the Federal University in Rio de Janeiro, said via email.

And "the strangeness did not stop there," Thiago Marinho, a paleontologist with the Federal University, added in an email. "This crocodyliform could [chew] like mammals do, like we do."

Most modern crocs simply use their powerful jaws to clamp down on their prey. But the fossil crocodile could move its lower jaw forward and backward, using its teeth to tear into dried meat, roots, pine branches, and mollusks, Marinho said.

Hot, Dry Climate

Paleontologists found the creature in 2005 in the Bauru region of São Paolo state, an area thought to have been hot and dry about 90 million years ago, noted de Souza Carvalho.

"Rainfall was seasonal, with flash-flood rivers. This is also uncommon to the living crocodiles and alligators that generally live in permanent waters," he said.

Armadillosuchus' arms and hands were likely capable of digging into the soil like those of armadillos.

"This could be a strategy to avoid dehydration in the arid environment—excavating holes in the soil—or to avoid other large crocodyliforms of that time," de Souza Carvalho said.

The team described the fossils in the February 2009 issue of the Journal of South American Earth Sciences. The fossils and life-like reconstructions went on display Tuesday at the Museu do Meio Ambiente do Jardim Botânico do Rio de Janiero.

credited to nationalgeographic.com

Prehistoric communities in one part of Peru’s Andes Mountains may have gone from maize to amazingly complex. Bioarchaeologist Brian Finucane’s analyses of human skeletons excavated in this region indicate that people living there 2,800 years ago regularly ate maize. This is the earliest evidence for maize as a staple food in the rugged terrain of highland Peru, he says.

Maize agriculture stimulated ancient population growth in the Andes and allowed a complex society, the Wari, to develop, Finucane contends in the August Current Anthropology. Wari society included a central government and other elements of modern states. It lasted from around 1,300 to 950 years ago and predated other Andes civilizations, including the Inca.

Scientists disagree about when and how civilizations formed in the Andes. One theory holds that complex societies, which perhaps fell short of states with centralized bureaucracies, first appeared at least 3,600 years ago in fishing villages along Peru’s coast and then spread inland. Based on remains of various wild and domesticated plants found at inland sites, other researchers suspect that agriculture had an especially big impact on the establishment of highland societies, beginning roughly 2,500 years ago. Questions also remain about whether prehistoric Andean civilizations depended primarily on maize or on a suite of crops including potatoes and beans.

Previous work has shown that prehistoric societies in the lowland areas of Central and North America depended on maize to grow large enough in numbers to develop state institutions, a pattern that Finucane sees paralleled in the Andes Mountains.

“These new findings indicate that intensive maize agriculture was the economic foundation for the development of the Wari state,” says Finucane, currently a law student at Yale University.

The new data convincingly demonstrate that highland residents relied on maize shortly before the rise of the Wari state, comments archaeologist Daniel Sandweiss of the University of Maine in Orono. A warmer, wetter climate during the Wari period and the spread of terraced cultivation areas may also have spurred maize farming, he suggests.

Not directly addressed by Finucane’s findings is whether ancient fishing villages provided the basis for later Andean civilizations, such as the Wari, says Sandweiss, a proponent of that hypothesis.

Finucane analyzed the chemical composition of bones from 103 individuals excavated by other researchers at six prehistoric sites in Peru’s Ayacucho Valley, one of several Andean regions where early civilizations arose. Ratios of certain chemical isotopes that collect in bone reflect the types of foods that an individual consistently consumed over at least the last decade of life.

Radiocarbon measurements of human bones at each site yielded age estimates that ranged from 2,800 years to 900 years. This time span encompasses three eras of Ayacucho prehistory: the Formative period of small farming villages, the Huarpa period of expanded settlements and irrigated fields, and the Wari period of centralized bureaucracy and state government.

Chemical signatures of substantial maize consumption appeared in the bones of individuals from every Ayacucho site, including three from Formative period sites, Finucane says.

Only a relatively small part of the Andean valley contains soil suitable for maize cultivation. Competition for cropland, he speculates, may account for evidence of considerable warfare during the Huarpa and Wari periods.

Finucane “makes a strong case” for maize as a key food in the Ayacucho Valley by about 1,800 years ago, but not 2,800 years ago as argued in his new paper, remarks Yale University anthropologist Richard Burger, who was not involved in the study. Only one skeleton in Finucane’s sample can be definitively dated to the Formative period, and signs of maize consumption in that specimen remain preliminary, in Burger’s view.

Finucane’s proposal is not out of the question, though. Another recent study of bone isotopes suggests that maize was regularly eaten at highland Andes sites in Argentina beginning around 4,000 years ago, says anthropologist Robert Tykot of the University of South Florida in Tampa. Tykot co-authored that investigation.

Chemical analyses are needed of other human skeletons that have been found at Formative period sites, Burger adds. Investigations of prehistoric diets in Andes valleys located at higher altitudes than Ayacucho will offer additional insights.

credited to sciencenews.org

It has been 400 years since English explorer Henry Hudson mapped the northeast coast of North America, leaving a wake of rivers and towns named in his honor, yet what happened to the famed explorer remains a mystery.

Hudson was never heard from again after a mutiny by his crew during a later voyage through northern Canada. That he died in the area in 1611 is a certainty, and he may have even been killed in cold blood, according to new research.

"The full story of Hudson's saga reveals one of the darker chapters of the European age of discovery," said Mancall, who explores the 1610 voyage in his new book "Fatal Journey: The Final Expedition of Henry Hudson" (Basic Books; 2009).

Before the fatal voyage that took his life, Henry Hudson found great success as a navigator the way many men did during the Age of Exploration — by accident.

Hired by the Dutch East India Company to find a new passage to spice-rich Asia by way of the Arctic Ocean, Hudson was ultimately forced by impassable ice to seek another route south. Sailing into what would eventually be named the Hudson River in 1609, he did not find the Northwest Passage he was looking for, but did manage to stake the first loose claim to the territory — including the island of Manhattan — on behalf of The Netherlands.

The value of the land he'd claimed for a foreign power wasn't lost on the rulers of his home country. Upon his return, England's royal council forbid Hudson from ever sailing under another flag, and he was sent back to the New World in 1610 aboard the English ship Discovery.

Hudson's objective was, once again, to find a northern passage to Asia, but he would never return from that trip. The Discovery docked back in London in 1611 without having reached Asia, without the captain aboard and with just eight crew, all of whom were now subject to death by hanging for the murder.

Some facts about the 1610-1611 voyage of the Discovery are certain.

Discovery plied the Canadian bay that also took Hudson's name in the summer of 1610, the captain believing that he'd possibly found the elusive northern passage to the Pacific. The ship was forced to ground itself for the winter, however, with Hudson ordering a return to the route the next spring, despite his crew's wish to return to England. When the ship took to the water again for its return trip in June 1611, Hudson was not aboard.

On trial for Hudson's murder later that year, the remaining crew admitted to cutting the captain and a group of individuals still loyal to him loose on a small lifeboat, according to court documents.

None of the men was convicted of the murder or even punished for the mutiny, and historians generally believe their claims, too. But some physical evidence points to a more violent end for the captain, Mancall believes.

Mancall highlighted evidence that was found and documented after the ship docked in London: blood stains, most damningly, along with letters from another sailor mentioning the growing personal rift between captain and crew. A number of Hudson's possessions were also missing.

Since Hudson's body was never found, however, it will never be known for sure whether the captain was murdered or given a more subtle death sentence, set adrift in the harsh environment of northern Canada.

It was Hudson's steely nature to press on and meet his objective that led to his demise, whatever that may have been, historians agree.

"Hudson was one of the most intrepid and important explorers of his age," said Mancall. "He was not a man who easily gave up."

credited to msnbc.msn.com

Australian palaeontologists say they have discovered three new dinosaur species after examining fossils dug up in Queensland.

Writing in the journal PLOS One, they describe one of the creatures as a fearsome predator with three large slashing claws on each hand.

The other two were herbivores: one a tall giraffe-like creature, the other of stocky build like a hippopotamus.

The fossils date back nearly 100m years to the middle of the Cretaceous period.

They were found in rocks known as the Winton Formation.

Beyond velociraptor

Queensland Museum palaeontologist, Scott Hucknell, said the carnivore, Australovenator wintonensis, was even bigger and more terrifying than velociraptor made famous in the Jurassic Park movies.

"The cheetah of his time, Banjo was light and agile. He could run down most prey with ease over open ground," he told reporters.

The dinosaurs have been named after characters in Australia's famous song, Waltzing Matilda.

The carnivore has been named named after Banjo Patterson, who composed Waltzing Matilda in Winton in 1885, the Sydney Morning Herald newspaper explained.

Clancy, Witonotitan wattsi, was a tall slender animal, while Matilda, Diamantinasaurus matildae, was more stocky and hippo-like.

These two plant-eating, four-legged sauropod species are new types of titanosaurs - the largest animals ever to walk the earth.

Banjo and Matilda - possibly predator and his prey - were found buried together in a 98m year old billabong, or stagnant pond.

Breakthrough

The find was published in the public access journal Public Library of Science One, and was announced by Queensland Premier Anna Bligh at the Australian Age of Dinosaurs Museum of Natural History in Winton.

She said the discoveries were a major breakthrough in the scientific understanding of prehistoric life in Australia.

Museum Victoria palaeontologist, John Long, said the finds were "amazing".

The newspaper quoted him saying that the finds put Australia back on the international map of big dinosaur discoveries for the first time since 1981, when the discovery of Muttaburrasaurus, a large four-legged herbivore that could rear up on two legs, was announced.

The new species will be part of the Australian Age of Dinosaurs Museum of Natural History under construction in Winton. This aims to house the world's largest collection of Australian dinosaur fossils when it is completed in 2015.

credited to news.bbc.co.uk

New Zealand's best known palaeontologist, self-taught Havelock North fossil hunter Joan Wiffen, has died aged 87.

Mrs Wiffen, who became known as the Dinosaur Lady, died suddenly in Hastings Hospital on Tuesday.

Her dig at Maungahouanga in Hawke's Bay was the first known site where dinosaurs lived in New Zealand.

Mrs Wiffen was the author and co-author of more than a dozen scientific papers and wrote of her achievements in her book Valley of the Dragons.

Born in 1922 and brought up in the King Country and Hawke's Bay during the 1930s Depression, Mrs Wiffen later recalled marvelling at the presence of sea shells high in the hills.

But she had only a brief secondary education – her father believed higher education was wasted on girls and she was expected to get married and have a family.

She served in the Women's Auxiliary Air Force during World War 2 and worked for six years as a clerk before marrying Pont Wiffen in 1953.

The couple raised their two children at Haumoana near Hastings, and the family hobby was rock collecting – they gathered minerals and fossils from throughout New Zealand and Australia.

Her husband enrolled in night classes in geology, and when he was ill, she went in his place and recalled being "green with envy" when someone found a fossil shell in mudstone.

"I knew what I wanted – to collect fossils," she said later.

Following an old geological map indicating reptilian bones in the Te Hoe Valley, she found the tail bone of a theropod dinosaur in the Maungahouanga valley in northern Hawke's Bay in 1975.

Mrs Wiffen went on to find bones from half a dozen other dinosaurs, including an armoured ankylosaur, a hypsilophodont, as well as a pterosaur flying reptile, and marine reptiles, such as mosasaurs and plesiosaurs.

In 1999, she found bone from one of the largest known dinosaurs, a titanosaurid: "I saw a partly exposed concretion (sedimentary rock) about the size of a rugby ball in the stream bank. I dug it out and asked a colleague to break it open with a hammer," she said afterwards.

"I immediately saw a bone structure inside that looked different from the bone of a marine reptile."

Friends and family helped her recover heavy sandstone rock from which she extracted the fossils with painstaking cutting and grinding and use of acid baths.

In 1994, she received an honorary doctorate from Massey University and the following year a CBE.

In 2004, she accepted the Morris Skinner Award from the United States-based Society of Vertebrate Palaeontology for outstanding and sustained contributions to scientific knowledge.

Her fossil finds are held in the palaeontology collection of GNS Science, with some on loan to Te Papa.

A spokesman at GNS said her scientific endeavours spanned arduous field work, painstaking fossil preparation, taxonomic description and palaeontological interpretation.

"Her contributions were extremely important nationally and give New Zealand geographic position, internationally," the institute said.

She also promoted palaeontology through contributions to popular books and articles, public lectures and school presentations.

Mrs Wiffen is survived by her son and daughter and a stepson and their families.

credited to stuff.co.nz

A Princeton University geoscientist who has stirred controversy with her studies challenging a popular theory that an asteroid wiped out the dinosaurs has compiled powerful new evidence asserting her position. Gerta Keller, whose studies of rock formations at many sites in the United States, Mexico and India have led her to conclude that volcanoes, not a vast meteorite, were the more likely culprits in the demise of the Earth's giant reptiles, is producing new data supporting her claim.

Keller, a Princeton professor of geosciences, and several co-authors lay out the case in a paper published April 27 in the Journal of the Geological Society of London. Examinations at several new sites have produced "biotic evidence" -- the fossilized traces of plants and animals tied to the period in question -- indicating that a massive die-off did not occur directly after the strike but much later.

In addition, Keller and other researchers have found "aftermath" sediments that remained undisturbed and showed signs of active life, with burrows formed by creatures colonizing the ocean floor. This would quash a theory advanced by some that a massive tsunami followed the impact, Keller said.

"Careful documentation of results that are reproducible and verifiable will uncover what really happened," Keller said. "This study takes an important step in that direction."

Much of the new data comes from a trench dug out of low-lying hills in northeastern Mexico at a site called El Peñon. A group of Princeton undergraduates accompanying Keller on a field trip to Mexico in 2004 excavated the area and uncovered the new evidence. Keller and her team have been analyzing that evidence for the last several years.

Understanding what caused the dinosaurs to disappear remains a great mystery. Theories attempting to explain it include asteroid or cometary impacts, volcanoes, global climate change, rising sea levels and supernova explosions. Scientists know that at a point about 65 million years ago, some phenomenon triggered mass extinctions on the land and oceans.

This event defines the boundary between the older Mesozoic Era, the "Age of Reptiles," and the modern Cenozoic Era, the "Age of Mammals." On a finer geological scale, the disappearances occurred between the Cretaceous (K) period and the Tertiary (T) period. As a result, scientists refer to this time as the K-T boundary.

At many locations, the K-T boundary is clearly visible in rock formations, which contain a thin layer of clay rich in the element iridium. Because iridium is more common in asteroids and comets than on Earth, scientists proposed in 1980 that an asteroid or comet must have struck Earth just at the boundary and caused the mass extinction of dinosaurs and many other animals. They thought they had found the culprit when they discovered the Chicxulub impact crater in Mexico's northern Yucatan.

Keller began studying the K-T boundary in 1984 -- the year she arrived at Princeton. She discovered that the evidence for the asteroid theory was not so clear. In field investigations, she and her team of students and collaborators found populations of Cretaceous age foraminifera, one-celled ocean organisms that evolved rapidly during select geological periods, living on top of the impact fallout from Chicxulub. The fallout from the asteroid that struck Chicxulub is visible as a layer of glassy beads of molten rock that rained down after the impact. If this impact caused the mass extinction, then the foraminifera above the impact glass beads should have been the newly evolved species of the Tertiary age.

Using these fossil remains to construct a timeline, she and her team were able to date the surrounding geologic features and begin to piece together proof that the impact occurred 300,000 years before the great extinction.

Over the years, Keller's group has amassed evidence for as many as four major events widely separated in time in that area of Mexico as well as in Texas. The oldest of the four events is the Chicxulub impact, seen by the fallout of glass beads. The second is about 150,000 years later and seen in a layer of sandstone with Chicxulub impact glass beads that were transported from shallow shore areas into deep waters during a sea level fall and was commonly interpreted as a tsunami generated by the Chicxulub impact. About 100,000 to 150,000 years later, the third event struck at the time of the K-T boundary with its iridium layer and mass extinction. This event may represent a second large impact or massive volcanism. The fourth event is possibly a smaller impact as evidenced by another iridium layer about 100,000 years after the mass extinction.

Advocates of the Chicxulub impact theory suggest that the impact crater and the mass extinction event only appear far apart in the sedimentary record because an earthquake or tsunami caused slumps and mixing of sediments surrounding the Gulf of Mexico. To date no evidence of major disturbance has been found in the sediments.

Keller says her team's newest research, however, confirms what she has found in earlier studies -- that the sandstone complex that overlays the impact layer was not deposited over hours or days by a tsunami but over a long time period. From El Peñon in Mexico and other sites listed in the new study, the scientists were able to calculate that between 13 and 30 feet of sediments were deposited at a rate of about an inch per thousand years after the impact. These sediments separating the impact layer from the sandstone complex and the overlying mass extinction were formed by normal processes. There is evidence of erosion and transportation of sediments in the sandstone layers, but no evidence of structural disturbance, Keller said.

Also at El Peñon, the researchers found 52 species present in sediments below the impact layer and counted all 52 still present in the layer above it, indicating that the impact has not had the devasting biotic effect on species diversity as has been suggested. "Not a single species went extinct as a result of the Chicxulub impact," Keller said.

In contrast, she noted, at a nearby site known as La Sierrita where the K-T boundary, iridium anomaly and mass extinction are recorded, 31 out of 44 species disappeared from the fossil record at the K-T boundary.

"Keller and colleagues continue to amass detailed stratigraphic information supporting new thinking about the Chicxulub impact and the mass extinction at the end of the Cretaceous," said Richard Lane, program director in the National Science Foundation's division of earth sciences, which funded the research. "The two may not be linked after all."

Keller suggests that the massive volcanic eruptions at the Deccan Traps in India may be responsible for the extinction, releasing massive amounts of dust and gases that could have blocked sunlight, altered climate and caused acid rain. The fact that the Chicxulub impact seems to have had no effect on biota, she said, despite its 6-mile-in-diameter size, indicates that even large asteroid impacts may not be as deadly as imagined.

She regards the latest evidence as sufficiently convincing and compelling to allow her to move on and investigate further the evidence for Deccan volcanism as being at the root of dinosaur extinction. But she does not expect her teams' present work will stop the raging debate at the heart of this controversy.

"The decades-old controversy over the cause of the K-T mass extinction will never achieve consensus," Keller said. But consensus, she added, is not a precondition to advancing science and unraveling truth. "What is necessary is careful documentation of results that are reproducible and verifiable," she said.

credited to esciencenews.com

Scientists have performed the first DNA-based reconstruction of the giant extinct moa bird, using prehistoric feathers recovered from caves and rock shelters in New Zealand.

The giant birds – measuring up to 2.5 metres and weighing 250 kilograms – were the dominant animals in New Zealand’s pre-human environment but were quickly exterminated after the arrival of the Maori around 1280AD.

PhD student Nicolas Rawlence from the University’s Australian Centre for Ancient DNA says until now, the scientific community has not known what the 10 different species of moa looked like. ”By using ancient DNA we have been able to connect feathers to four different moa species,” he says.

The researchers compared the feathers to others found in the sediments from red-crowned parakeets that are still living today, determining they had not faded or changed in colour. They then reconstructed the appearance of the stout-legged moa, heavy-footed moa, upland moa and the South Island giant moa.

“The surprising thing is that while many of the species had a similar, relatively plain brown plumage for camouflage, some had white-tipped feathers to create a speckled appearance,” Mr Rawlence says.

A co-author of the study, Dr Jamie Wood from Landcare Research, says it is likely that the drab colouring was driven by selection to avoid predation by the extinct Haast’s eagle, the largest and most powerful eagle in the world.

The research team also demonstrated that it is possible to retrieve DNA from all parts of the ancient feathers, not just the tip of the quill, as previously thought.

“This important finding opens the way to study DNA from museum bird skins while causing almost no damage to these valuable specimens, just by clipping a small part of a single feather,” says Dr Kyle Armstrong from the Australian Centre for Ancient DNA (ACAD).

ACAD Director Professor Alan Cooper says this finding suggests it may be possible to reconstruct the appearance of other extinct birds using feathers from fossil deposits.

“There are so many enigmatic extinct species that it would be great to see ‘clothed’," Professor Cooper says.

credited to University of Adelaide (2009, June 30). Giant Moa Rebuilt Using Ancient DNA. ScienceDaily. Retrieved July 1, 2009, from http://www.sciencedaily.com­ /releases/2009/06/090630215938.htm

By scanning a 54-million-year-old skull roughly the size of a walnut, scientists have created the first virtual 3-D model of an early primate brain, a new study says. Surprisingly, the model suggests that primates (such as lemurs, monkeys, apes, and humans, among others) might have evolved larger brains as a result of the need to move quickly from tree to tree—not, as commonly assumed, to hunt for fruit or navigate within a single tree.

Discovered in Wyoming roughly 25 years ago, the fossil "is the most complete early primate skull known," said study co-author Jonathan Bloch, a vertebrate paleontologist at the University of Florida.

Due to its completeness and age, the skull gives us the clearest idea yet what early primates were like, the researchers argue. Even so, they say more early-primate fossils are needed to test the study's conclusions.

Doing More With Less

After taking more than 1,200 detailed X-ray images of the skull, researchers combined them to help create a 3-D model of Ignacius' brain.

The model showed a brain just one-half to two-thirds the size of the smallest modern primate brain, the study says.

And yet that seems to have been enough for tree dwelling and fruit seeking. Ignacius' teeth, for example, suggest it had a fruit diet, while the animal's claws and flexible joints hint at tree dwelling.

The finding therefore reopens the question of what triggered the evolution of large brains in later primate species, if not branch living or fruit eating?

The Eyes Didn't Have It

One activity Ignacius seems unsuited for is jumping from tree to tree, as opposed to simply climbing branches. In primates, this type of leaping generally requires long hind limbs, large inner-ear organs linked to balance—and strong visual processing.

Instead of a robust center of vision, Ignacius' brain had large lobes dedicated to smelling, the model suggests.

The prehistoric primate "was mostly a nose-first animal that relied on smell instead of sight, unlike modern primates, which have far more developed visual processing areas," explained lead study author Mary Silcox, a vertebrate paleontologist at the University of Winnipeg.

For primates, "stepping up vision would have been key for leaping safely," she surmised. But that apparently would have to wait until the time—and the brain—was right.

credited to news.nationalgeographic.com