Fossil Of 'Giant' Shrew Nearly One Million Years Old Found In Spain
Morphometric and phylogenetic analyses of the fossilised remains of the jaws and teeth of a shrew discovered in a deposit in Gran Dolina de Atapuerca, in Burgos, have shown this to be a new species (Dolinasorex glyphodon) that has not previously been described. The extinct animal had red teeth, was large in size compared with mammals of the same family, and was more closely related to Asian than European shrews."To date, all the medium to large-sized Soricidae fossils discovered in the deposits of the Sierra de Atapuerca belonged to Beremendia fissidens, a species of plio-pleistocene shrew that was distributed throughout Europe," said Juan Rofes, lead author of the study that has been published recently in the Zoological Journal of the Linnean Society and a researcher in the Paleontology Department at the UNIZAR.
The morphometric and phylogenetic studies of the new species reveal a close link with the species of eastern Asia, where it could have arisen and evolved before migrating to the Iberian Peninsula.
In addition, analyses of jawbones and individual teeth of Dolinasorex glyphodon, collected between 1991 and 2007 in Atapuerca, have enabled the scientists to develop paleoecological and biogeographical hypotheses, suggesting that the animal lived in an epoch characterised by a warm, wet and relatively stable climate, and that "the origin and initial dispersal of this shrew would have been in and from the Asian continent," adds Rofes.
A shrew with the looks of the devil
Dolinasorex glyphodon was a shrew with red teeth that belonged to the Soricinae sub-family. By using allometric calculations (relating to changes in the size of body parts in comparison with changes in the overall size of the animal), the researchers have described it as "giant". Compared with a modern, large-sized member of the Soricidae family, such as the water shrew (Neomys fodiens), which weighs in at around 14 grams, the body mass of the extinct shrew reached 60 grams.
The study of the fossil remains of this mammal has also made it possible to discover that the shrew injected toxic saliva, in the same way that snakes do, via a "narrow and conspicuous channel" located on the inside surface of its lower incisors. "This was a mechanism very similar to that of the modern solenodons and almiquis, which are close relatives of the shrews and live on the islands of Cuba and Haiti," explains Rofes.
Although the remains of shrews are frequently found in paleontological deposits, their presence is due above all to the feeding habits of birds of prey, which "feed on micro-vertebrates and then regurgitate the skin, hair and bones in conglomerate pellets," adds the expert.
Comparisons with faunal associations from many other European deposits have enabled the discoverers of Dolinasorex glyphodon to describe it as endemic, and it is the first genus of Soricidae to be described on the Iberian Peninsula to date. However, Rofes and his team warn that "the results of this phylogenetic study are only a first step and not at all definitive, but they could be of great interest for more complete studies in the future."
credited to Plataforma SINC (2009, May 18). Fossil Of 'Giant' Shrew Nearly One Million Years Old Found In Spain. ScienceDaily. Retrieved May 19, 2009, from http://www.sciencedaily.com /releases/2009/05/090518103229.htm
Competition May Have Led To New Dinosaur Species In Northwestern Alberta
The discovery of a gruesome feeding frenzy that played out 73 million years ago in northwestern Alberta may also lead to the discovery of new dinosaur species there.Miyashita and Fanti came across a nesting site and found the remains of baby, plant-eating dinosaurs and the teeth of a predator. The researchers matched the teeth to a Troodon, a raptor-like dinosaur about two metres in length. This finding has opened new doors in dinosaur research on this part of the continent: "It established that dinosaurs were nesting at this high latitude," said Miyashita. "It also shows for the first time a significant number of Troodons in the area [who] hunted hatchling dinosaurs."
Over the course of two summers of field work Miyashita and Fanti began building a theory that Grande Prairie is a "missing link" between known dinosaur species that existed much further to the north and south. "Prior to this there were no localities with a variety of dinosaurs and other animals between Alaska and southern Alberta," said Myiashita. The list of new finds for the area includes armoured and thick-headed plant eaters and fossilized freshwater fish and reptiles.
Miyashita says this small pocket of previously undiscovered life could have had interactions that lead to the evolution of new species.
"New dinosaurs weren't created by interbreeding," said Miyashita. "Having a variety of dinosaurs in one area creates new ecological interactions such as competition for food and predation.
"That can lead to the evolution of a new species."
One Grande Prairie dinosaur the researchers suspect is a new species is the Duck bill. Miyashita says unlike the Duck bill found further north in Alaska, the Grande Prairie has a visible bump or crest on its forehead. The pair will go back to Grande Prairie area in 2010 to focus on finding other dinosaur species in the area.
credited to University of Alberta (2009, May 15). Competition May Have Led To New Dinosaur Species In Northwestern Alberta. ScienceDaily. Retrieved May 18, 2009, from http://www.sciencedaily.com /releases/2009/05/090512134657.htm
Giant Dinosaurs Stuck Their Necks Out, Not Up?
Long-necked dinosaurs didn't graze treetops, according to new research that suggests the prehistoric animals were better off holding their necks horizontal, not upright.Since long-necked modern animals, such as giraffes, tend to browse on leaves in tall trees, paleontologists have assumed that sauropods—whose necks could be as long as 30 feet [9 meters]—must have done the same.
But Roger Seymour, of the University of Adelaide in Australia, found that sauropods would have spent as much as 75 percent of their bodies' energy to keep their heads held high.
Most mammals use about 10 percent of their energy to circulate blood through their bodies. Giraffes use about 18 percent of their energy to keep blood moving through their long, upright necks.
"Would the increased availability of food in tall trees be worth the cost? This seems doubtful," Seymour said. "It would probably make more energetic sense for [sauropods] to feed with their necks close to horizontal."
By moving their necks side-to-side horizontally, sauropods would have been able to feed on a very large area of plant material without having to move their bodies.
That may not seem like a much of an energy-saving tactic. But in animals that may have weighed 30 to 40 tons, the energetic difference between taking a few steps and not taking a few steps may have been as huge as the animals themselves.
Expensive Treats
Still, some scientists not involved with Seymour's research argue that, in extreme cases, it may have been worth it for saurpods to spend the extra energy to lift their necks.
The bones and joints in some of these animals show that they could lift their necks between 30 and 60 degrees above horizontal, paleontologist Martin Sander, of the University of Bonn in Germany, said.
When food availability at low and medium heights became scarce, the cost of raising the head to get valuable resources may have been worth it, Sander said.
Richard Cowen, of the University of California, Davis, noted that other animals sometimes expend enormous amounts of energy on food.
Cheetahs, for example, sprint after prey, even though the big cats only make the catch one time in four. Likewise, whales use massive amounts of energy to dive deep into cold water, and migratory birds burn heaps of energy flying thousands of miles.
All of these behaviors could be viewed as incredible energy sinks, but we know they are not because the animals gain something significant in return that makes the energy expenditure worth it, Cowen explained.
"It would be reasonable for sauropods to browse occasionally with heads high, as long as the payoff was also high," Cowen said.
Ancient Elite Island With Pyramid Found in Mexico
An island for ancient elites has been found in central Mexico, archaeologists say. Among the ruins are a treasury and a small pyramid that may have been used for rituals."If you would paddle up to the island [during the time], you would see a number of buildings, some temples with smoke coming out of them from rituals, and a small village of specialized people—priests, elites," Fisher said.
The Purépecha people—named Tarascan by the Spanish—were formidable enemies with their neighbors, the Aztec. From their powerful capital city and religious center Tzintzuntzan, the Tarascans successfully thwarted every attack by the Aztec.
Tarascan people valued such products as honey, cotton, feathers, and salt, and they often expanded into neighboring lands in search of these goods.
Ritual Center
Fisher and colleagues found a square structure with a formal entrance that is believed to have been an imperial treasury.
Adjacent to the treasury is a small pyramid, which has large, open rooms that would have been suitable for ritual activity. Pipe fragments were also found near the treasury.
The pipe discoveries may bear out ritual descriptions on a previously found ancient Spanish scroll.
The scroll shows people smoking pipes and drinking pulque—a drink made of agave, a crucial crop used for alcoholic drinks, such as tequila, and syrup, Fisher said.
The scroll also describes ritual treasury caches dedicated to specific gods.
"These caches were also used to finance activities like warfare," said Fisher, who has submitted a report describing his as yet unpublished research to Mexico's National Institute of Anthropology and History.
Toward the end of the island's Tarascan occupation, the area was a "ritual center" where people of elite status lived and worked, he added.
The team identified a colonial-era chapel from the early 1500s, built in the first 20 years of the Spanish conquest.
Evidence of crop cultivation also suggests that humans continuously occupied the site for 2,000 years, Fisher said.
The entire island was covered in agricultural terraces, possibly to grow agave.
People created the terraces by digging sections of land about 6.6 feet (2 meters) wide, with earthen walls and a ditch on either side.
Filling in Gaps
"The discovery fills in gaps in the Lake Pátzcuaro basin's chronology," said Helen Perlstein Pollard, professor of anthropology at Michigan State University who has worked with Fisher in Mexico's Tarascan region.
"He discovered the basic sequence of occupation, the repeated use of this island over time, and the way the use of the island has shifted over time," Perlstein Pollard said.
Now, archaeologists can begin to examine the relationship between settlement patterns and the economic and political structures on the islands.
"We can now begin to ask the interesting questions," she said.
credited to news.nationalgeographic.com
Will We Ever Find Atlantis?
The story endures as a classic in the genre of lost worlds long vanished, the ruins and treasures of which are surely somewhere out there yet to be found. Legends, though, are often mirages, forever shimmering out of reach, yet exerting an attractive power beyond reason.
Sometimes the pursuit of legends leads to unforeseen knowledge.
In the 12th century A.D., the legend of Prester John, a rich and powerful Christian monarch somewhere in Asia, drew intrepid seekers, eventually including Marco Polo, who opened Western eyes to the wonders of the East. When no one found Prester John in Asia, the legend did not go away; its locale shifted to Africa.
The golden city of El Dorado eluded hellbent adventurers, whose frustrated quest nonetheless put much of South America on the map.
The fabled Seven Cities of Cibola, castles in the air that proved to be nothing more than humble Indian pueblos, drew Europeans across tortured miles and years of discovery in what is now the Southwestern United States.
The tale of the lost continent has sent respected classical scholars to their texts for corroboration that Atlantis was more than fantasy. Archaeologists, geologists and divers have plumbed ocean depths where the island supposedly sank out of sight thousands of years ago. Not a scrap of compelling evidence supporting the legend has ever turned up.
Such a negative discovery might be conclusive enough for most legends to pass from rock-hard belief to literary artifacts of prescientific cultures living in a world of limited horizons and boundless mystery. But true believers, complaining that scientists have got it all wrong, continue the search.
Generations of adventurers, writers, mystics and cranks have satisfied themselves of the legend's reality. Their ''solutions'' fill more than 2,000 books and countless articles. The lost continent also inspired works by authors as diverse as Francis Bacon and Arthur Conan Doyle, and Hollywood has weighed in with any number of forgettable movies.
Richard Ellis, author of ''Imagining Atlantis,'' thinks the legend is fantasy. ''Atlantis lives on in people's minds largely because you cannot prove it doesn't exist,'' he said recently. ''You can't search every inch of the ocean bottom, and so the hope remains alive and the promise of finding treasures in sunken palaces.''
The sole source of the Atlantis story is by no means obscure. In two dialogues, the ''Critias'' and the ''Timaeus,'' Plato in the fourth century B.C. described a resplendent island empire in the Atlantic Ocean beyond the Pillars of Hercules (the Strait of Gibraltar). ''This dynasty, gathering its whole power together,'' Plato wrote, ''attempted to enslave, at a single stroke, your country and ours.''
Even after disbelief in ancient gods undercut literal acceptance of the legend, medieval maps were sprinkled with imaginary islands in the Atlantic, including Antillia. Some experts suspect this preserves in garbled form the name of Atlantis and a lingering belief that its remnants may still exist. The maps encouraged navigators in their quests, among them Columbus.
The 20th century was hard on Atlantis dreams. Detailed mapping of the sea floor and the new theory of plate tectonics made it clear, geophysicists say, that land masses resembling Atlantis never existed in the Atlantic.
Undeterred, ardent believers went looking elsewhere: in Scandinavia, the Bahamas and the Aegean Sea. Huge blocks of stone submerged off Cuba were recently proclaimed possible ruins of the lost empire.
A more plausible hypothesis, some scholars think, places Atlantis at Crete. The accomplished Minoan civilization there collapsed in the middle of the second millennium B.C., presumably destroyed by a volcanic eruption on nearby Thera, modern Santorini.
Was this in Plato's mind? Or he might have been inspired by an event in his own time, the earthquake in 373 B.C. that brought the Greek city of Helike, as ancient writers said, crashing into the sea.
The unknown fires the imagination. Whether the starry night or extraterrestrial beings, the mystery of life itself or life after death or any of the uncertain boundaries between reality and resolute yearning, it is unknowns that populate history with gods and heroes, monsters of the deep and chimeric islands, lost paradises and the elusive El Dorado at the end of greed's rainbow, not to mention Martians.
Some mysteries will be solved, but never all of them. As for Atlantis, another Greek philosopher delivered the verdict that has yet to be contradicted.
As noted by the British classicist J. V. Luce, Aristotle considered Atlantis a poetic fiction invented by Plato as a warning of the fate that befalls the arrogant and decadent. Plato placed Atlantis beyond the then known world and sank it to the ocean floor to preserve the power of the mystery.
''The man who dreamed it up made it vanish'' was Aristotle's solution to the mystery of Atlantis.
credited to nytimes.com
Biggest Trilobite Sea Beasts Found ... in Swarms
Talk about ruining a good beach day. Swarms of up to a thousand giant trilobites—extinct marine arthropods such as this 35-inch-long (90-centimeter-long) fossil specimen—roamed shallow prehistoric seas, new fossils show.The trilobites may have clustered to mate and molt—shedding old exoskeletons as new ones grew in—as well as avoid predators, scientists say.
The benefits of swarming may explain why these distant relatives of horseshoe crabs were among the most widespread arthropods of the Paleozoic era (542 to 251 million years ago).
Even so, finding complete specimens bigger than 12 inches (30 centimeters) is rare—making the new find "remarkable," the study authors write in a recent edition of the journal Geology.
The critters lived at high latitudes near Gondwana—a huge southern supercontinent—and close to the South Pole during the Ordovician period (map of Earth during the Ordovician period).
This oxygen-rich, cold-water habitat may have contributed to these trilobites' gigantic sizes, the authors added.
But repeated, sudden, "lethal" influxes of oxygen-starved water may have led to the newfound trilobites' demise millions of years ago.
credited to news.nationalgeographic.com
Rise Of Oxygen Caused Earth's Earliest Ice Age
Geologists may have uncovered the answer to an age-old question - an ice-age-old question, that is. It appears that Earth's earliest ice ages may have been due to the rise of oxygen in Earth's atmosphere, which consumed atmospheric greenhouse gases and chilled the earth."We can now put our hands on the rock library that preserves evidence of irreversible atmospheric change," said Kaufman. "This singular event had a profound effect on the climate, and also on life."
Using sulfur isotopes to determine the oxygen content of ~2.3 billion year-old rocks in the Transvaal Supergroup in South Africa, they found evidence of a sudden increase in atmospheric oxygen that broadly coincided with physical evidence of glacial debris, and geochemical evidence of a new world-order for the carbon cycle.
"The sulfur isotope change we recorded coincided with the first known anomaly in the carbon cycle. This may have resulted from the diversification of photosynthetic life that produced the oxygen that changed the atmosphere," Kaufman said.
Two and a half billion years ago, before the Earth's atmosphere contained appreciable oxygen, photosynthetic bacteria gave off oxygen that first likely oxygenated the surface of the ocean, and only later the atmosphere. The first formed oxygen reacted with iron in the oceans, creating iron oxides that settled to the ocean floor in sediments called banded iron-formations - layered deposits of red-brown rock that accumulated in ocean basins around the worldwide. Later, once the iron was used up, oxygen escaped from the oceans and started filling up the atmosphere.
Once oxygen made it into the atmosphere, Kaufman's team suggests that it reacted with methane, a powerful greenhouse gas, to form carbon dioxide, which is 62 times less effective at warming the surface of the planet. "With less warming potential, surface temperatures may have plummeted, resulting in globe-encompassing glaciers and sea ice" said Kaufman.
In addition to its affect on climate, the rise in oxygen stimulated the rise in stratospheric ozone, our global sunscreen. This gas layer, which lies between 12 and 30 miles above the surface, decreased the amount of damaging ultraviolet sunrays reaching the oceans, allowing photosynthetic organisms that previously lived deeper down, to move up to the surface, and hence increase their output of oxygen, further building up stratospheric ozone.
"New oxygen in the atmosphere would also have stimulated weathering processes, delivering more nutrients to the seas, and may have also pushed biological evolution towards eukaryotes, which require free oxygen for important biosynthetic pathways," said Kaufman.
The result of the Great Oxidation Event, according to Kaufman and his colleagues, was a complete transformation of Earth's atmosphere, of its climate, and of the life that populated its surface. The study is published in the May issue of Geology.
credited to sciencedaily.com
Some Dinosaurs Survived the Asteroid Impact
The great splat of an asteroid that might have wiped out the dinosaurs apparently didn't get all of them. New fossil evidence suggests some dinosaurs survived for up to half a million years after the impact in remote parts of New Mexico and Colorado.Scientists recently analyzed dinosaur bones found in the Ojo Alamo Sandstone in the San Juan Basin. Based on detailed chemical investigations of the bones, and evidence for the age of the rocks in which they are found, the researchers think some dinosaurs outlived the crash that occurred 65 million years ago and stuck around for a while.
"This is a controversial conclusion, and many paleontologists will remain skeptical," said David Polly, one of the editors of the journal Palaeontologia Electronica, in which the research was published today.
Lead researcher Jim Fassett of the U. S. Geological Survey in Santa Fe, New Mexico went to great lengths to establish when the bones originated.
"The great difficulty with this hypothesis — that these are the remains of dinosaurs that survived — is ruling out the possibility that the bones date from before the extinction," he said. "After being killed and deposited in sands and muds, it is possible for bones to be exhumed by rivers and then incorporated into younger rocks."
To try to eliminate that scenario, Fassett investigated the rocks surrounding the bones and studied date indicators, such as their magnetic polarity. He said the evidence "independently indicate[s] that they do indeed post-date the extinction."
He also found that the dinosaur bones from the Ojo Alamo Sandstone have distinctly different concentrations of rare earth metal elements than the deeper, older rocks that date from the time of the impact. This suggests that it's unlikely the bones originated in that older rock and were somehow relocated to the more recent, higher level of sediment.
Another piece of evidence seems to support the claim, too. The fossil remains include a group of 34 hadrosaur bones lying together, which Fassett said are "doubtless from a single animal." If the bones had been exhumed from the older rock by a river, they would have likely been scattered in several locations, and wouldn't be clustered together as they are.
Even if the dinosaur bones do turn out to belong to disaster survivors, there probably were very few of them compared to their population before the crash.
"One thing is certain," Polly said. "If dinosaurs did survive, they were not as widespread as they were before the end of the Cretaceous and did not persist for long."
Whale Fossil Found in Kitchen Counter
After a factory had found a 40-million-year-old whale fossil in a limestone kitchen counter, researchers investigated the stone's fossil-packed Egyptian quarry, which could shed light on the origins of African wildlife.
New Blow Against Dinosaur-killing Asteroid Theory, Geologists Find
The enduringly popular theory that the Chicxulub crater holds the clue to the demise of the dinosaurs, along with some 65 percent of all species 65 million years ago, is challenged in a paper to be published in the Journal of the Geological Society on April 27, 2009.When spherules from the impact were found just below the Cretaceous-Tertiary (K-T) boundary, it was quickly identified as the "smoking gun" responsible for the mass extinction event that took place 65 million years ago.
It was this event which saw the demise of dinosaurs, along with countless other plant and animal species.
However, a number of scientists have since disagreed with this interpretation.
The newest research, led by Gerta Keller of Princeton University in New Jersey, and Thierry Adatte of the University of Lausanne, Switzerland, uses evidence from Mexico to suggest that the Chicxulub impact predates the K-T boundary by as much as 300,000 years.
"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," says H. Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research. "The two may not be linked after all."
From El Penon and other localities in Mexico, says Keller, "we know that between four and nine meters of sediments were deposited at about two to three centimeters per thousand years after the impact. The mass extinction level can be seen in the sediments above this interval."
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 of earthquake or tsunami disturbance that resulted from the impact of the asteroid.
"The problem with the tsunami interpretation," says Keller, "is that this sandstone complex was not deposited over hours or days by a tsunami. Deposition occurred over a very long time period."
The study found that the sediments separating the two events were characteristic of normal sedimentation, with burrows formed by creatures colonizing the ocean floor, erosion and transportation of sediments, and no evidence of structural disturbance.
The scientists also found evidence that the Chicxulub impact didn't have the dramatic impact on species diversity that has been suggested.
At one site at El Penon, the researchers found 52 species present in sediments below the impact spherule layer, and counted all 52 still present in layers above the spherules.
"We found that not a single species went extinct as a result of the Chicxulub impact," says Keller.
This conclusion should not come as too great a surprise, she says. None of the other great mass extinctions are associated with an impact, and no other large craters are known to have caused a significant extinction event.
Keller suggests that the massive volcanic eruptions at the Deccan Traps in India may be responsible for the extinction, releasing huge amounts of dust and gases that could have blocked out sunlight and brought about a significant greenhouse effect.
credited to National Science Foundation (2009, April 28). New Blow Against Dinosaur-killing Asteroid Theory, Geologists Find. ScienceDaily. Retrieved May 5, 2009, from http://www.sciencedaily.com /releases/2009/04/090427010803.htm
