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(Bio) Dinosaurs: Near-complete Titanosaurus in Argentina
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PostPosted: Tue Dec 27, 2005 1:07 pm    Post subject: (Bio) Dinosaurs: Near-complete Titanosaurus in Argentina Reply with quote






Near-complete Titanosaurus discovered in Argentina
Mon Dec 26, 3:12 PM ET

BUENOS AIRES (AFP) - Argentine paleontologists have discovered
the largely intact skeleton of a young titanosaurus that lived 71 million
years ago.

"What's extraordinary about this is that the remains were articulated, as
if the animal had fallen or lain down and remained that way. There were
no signs that it was preyed on," local media reported geologist and
paleontologist Bernardo Gonzalez Riga as saying.

Scientists discovered the remains of a foot "with all its toes and claws in
an exceptional state of preservation," as well as the complete rear
bones, tail, "and part of the pelvis," Gonzalez said.

Such finds are rare, said Gonzalez, adding that there are only one or two
titanosauruses in the world with complete feet.

Gonzalez is a professor at Cuyo University, one of two universities with
teams that excavated the remains.

"This now adds to that and brings new data of regional national and
international relevance," he said.

The remains were discovered while German petroleum company
Wintershall Energy was prospecting for oil in Nuequen province, where
many paleontological discoveries have been made.

An initial examination of the remains suggest a small young titanousaurus
about 10 meters (yards) long that weighed about 12 tons. The giant
herbivores, which grew up to 35 meters long, lived during the late
Cretaceous period (83-65 million years ago).

While the skeleton is almost complete from ribs to tale, there is no sign of
the head and neck, which were likely washed away over the millennia,
said Gonzalez.

The fossils were taken to the Lago Barreales Palentological Center in
Neuquen for analysis, the report said.

*************************************************************
Related Lessons (Elementary Level)


http://www.sciencenetlinks.com.....;DocID=358
http://www.sciencenetlinks.com.....;DocID=359

************************************************************
Questions to explore further this topic:

What is a titanosaurus?

http://en.wikipedia.org/wiki/Titanosaurus

What are dinosaurs?

http://www.ucmp.berkeley.edu/d.....osaur.html
http://www.ucmp.berkeley.edu/diapsids/dinolh.html
http://www.fieldmuseum.org/exh.....iassic.htm
http://www.dinodata.net/Kids/introduction.htm
http://www.christiananswers.ne.....rney0.html

What are saurischians?

http://www.ucmp.berkeley.edu/d.....schia.html

What are saurapods?

http://www.ucmp.berkeley.edu/d.....opoda.html

What are the time periods relevant to dinosaurs?

http://internt.nhm.ac.uk/jdsml.....sort=Genus
http://www.bbc.co.uk/schools/g.....rev8.shtml
http://www.dinodata.net/Kids/Timeperiods.htm
http://www.dinodata.net/Dd/Namelist/TIMES.htm

The Triassic Period

http://www.bbc.co.uk/sn/prehis.....mya1.shtml

The Jurassic Period

http://www.bbc.co.uk/sn/prehis.....mya1.shtml
http://www.bbc.co.uk/sn/prehis.....mya1.shtml
http://www.bbc.co.uk/sn/prehis.....mya1.shtml
http://www.bbc.co.uk/sn/prehis.....mya1.shtml
http://www.bbc.co.uk/sn/prehis.....mya1.shtml

How did the dinosaurs die?

http://www.bbc.co.uk/sn/prehis.....mya1.shtml
http://www.bbc.co.uk/sn/tvradi.....mary.shtml

How are dinosaurs classified?

http://www.ucmp.berkeley.edu/diapsids/dinosy.html
http://www.ucmp.berkeley.edu/diapsids/dinomm.html

Here are some paintings of dinosaurs by Artist Joe Tucciarone:

http://www.dinosauria.com/gallery/joe/joe.htm
http://www.dinosauria.com/gallery/joe/joe2.html
http://www.dinosauria.com/gallery/joe/joe3.html
http://www.dinosauria.com/gallery/joe/joe4.html

Here is a virtual trip to a dinosaur museum:

http://www.dinodata.net/Kids/vmus.htm

Here are some animations of dinosaurs:

http://www.dinodata.net/Kids/animation.htm

Here are some videos about dinosaurs:

http://www.dinodon.com/dinovideos.htm
http://www.carnegiemnh.org/car.....t/film.htm

What are fossils?

http://www.bbc.co.uk/sn/prehis.....g_fossils/

Where is Argentina

http://www.cia.gov/cia/publica.....os/ar.html

GAMES

http://www.bbc.co.uk/sn/prehistoric_life/games/


Last edited by adedios on Sat Jan 27, 2007 3:47 pm; edited 3 times in total
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PostPosted: Mon Jan 02, 2006 8:28 am    Post subject: From Mammoth to Modern Elephant Reply with quote

From Mammoth to Modern Elephant

Emily Sohn

Thousands of years ago, an elephant-like creature called the woolly mammoth roamed Earth. Except for fossilized bones and remains found trapped in ice, it's now gone. Scientists have long wondered whether the extinct mammoth is more closely related to today's African elephant or Asian elephant.

Modern elephants and woolly mammoths share a common ancestor that lived about 6 million years ago. Exactly how and when the species split over time, though, hasn't been clear. Now, researchers are using modern techniques to piece together ancient elephant history.

From looking at fossilized bones and other features, scientists had proposed that woolly mammoths are more closely related to Asian elephants than to African elephants. Tiny pieces of evidence from the genetic material DNA, on the other hand, hinted at the opposite conclusion.

Because DNA is often the most reliable way to trace evolutionary links, a team led by scientists at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, set out to document part of the mammoth genome, which is a map of the creature's DNA. Only recently has technology become available to recreate a genome based on old, damaged DNA.

The scientists first took just 200 milligrams of bone from a mammoth that had lived 12,000 years ago in northeastern Siberia. Then, they used a chemical reaction to make many copies of whatever pieces remained of the mammoth's DNA. Many of the pieces overlapped, so the scientists were able to put them together, like a jigsaw puzzle, into a complete whole.

In this study, the researchers focused on a type of DNA called mitochondrial DNA. It's a ring-shaped structure found inside a cell part called the mitochondrion. Analyses showed that the modern Asian elephant shares 95.8 percent of its mitochondrial DNA with the woolly mammoth. The modern African elephant has a slightly smaller overlap, sharing about 95.5 percent of its mitochondrial DNA with the woolly mammoth.

The difference suggests that African elephants were the first modern species to split from the main branch of the elephant family tree. Asian elephants and woolly mammoths branched off about 440,000 years later, the scientists say. In other words, Asian elephants are more closely related to mammoths than are African elephants.

An Asian elephant. The Asian elephant has smaller ears and a smaller forehead (with two big bumps) than the African elephant does. Usually only males have tusks. Its back arches up in the middle.

The findings should be weighed cautiously, some scientists warn, because looking only at mitochondrial DNA can be misleading. Instead, a group of researchers in Canada is using new high-speed machines to analyze every piece of DNA in the nucleus of a mammoth's cell.

Strands of DNA in the cell nucleus are millions of times longer than those in the mitochondrion, so the project may take a couple of years. When it's done, though, we may finally have a clear picture of the elephant family tree.—E. Sohn

http://www.sciencenewsforkids....../Note2.asp

From Science News for Kids Jan. 4, 2006.
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PostPosted: Mon Jan 02, 2006 8:30 am    Post subject: Dino Babies Reply with quote

Dino Babies

Emily Sohn

Some dinosaurs needed babysitters, too
Scientists have recently analyzed the oldest dinosaur eggs ever discovered with embryos still inside. The study suggests that the dinos couldn't take care of themselves when they first hatched, say the researchers, who come from the University of Toronto at Mississauga in Ontario. Just like human babies, the little dinosaurs relied on grown-ups for help.

The study closely examined two of seven eggs that were discovered 30 years ago in South Africa. The 190-million-year-old eggs belonged to a common plant-eating dinosaur called Massospondylus carinatus, the researchers say. Fully grown, the creatures measured about 5 meters (over 16 feet) long.

Six of the eggs held bones and other remains that filled their shells. That fact, plus the highly developed state of the bones, suggests that the baby dinos were nearly ready to hatch.

As big as the two embryos were, all of them had empty tooth sockets except one, which only had a single tooth. That means that M. carinatus babies were probably born without teeth or with teeth that were soft and so not preserved as fossils. The scientists say that the youngest of these dinosaurs wouldn't have been able to bite leaves off of trees. Adults would have had to feed them.

Grown-up M. carinatus walked on two legs. However, the shape of the embryo skeletons made the researchers conclude that the babies traveled on all fours. They had large heads, thick necks, and small pelvic bones, so they would have been awkward and in need of guidance from older, bigger relatives.

Funny enough, dinosaurs that lived later on were built like M. carinatus babies even as adults and grew up to be huge, weighing up to 100 tons and stretching up to 40 meters long. It's possible that these ancient embryos were an early sign of what was yet to come.—E. Sohn


http://www.sciencenewsforkids....../Note3.asp

From Science News for Kids Aug. 10, 2005.
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PostPosted: Thu Feb 09, 2006 7:56 am    Post subject: Early Version of T. Rex Is Discovered Reply with quote

Early Version of T. Rex Is Discovered
By MALCOLM RITTER, AP Science Writer
Wed Feb 8, 10:52 PM ET

Scientists say they've found the earliest known tyrannosaur, shedding light on the lineage that produced the fearsome Tyrannosaurus rex. The discovery comes with a puzzle: Why did this beast have a strange crest on its head?

Digging in the badlands of northwestern China that appeared in the movie "Crouching Tiger, Hidden Dragon," researchers found two skeletons of a creature that lived some 160 million years ago. That's more than 90 million years before T. rex came along.

A two-legged meat-eater, the beast was far smaller than T. rex, measuring about 10 feet from its snout to the tip of its tail and standing about 3 feet tall at the hip. It also sported relatively long, three-fingered arms, rather than the two-fingered stubby arms T. rex had. Scientists suspect it had feathers because related dinosaurs did.

The discovery is reported in Thursday's issue of the journal Nature.

The big surprise, said study co-author James Clark of George Washington University in Washington, D.C., was the finding of a narrow, delicate, largely hollow crest on its head. While other dinosaurs have had similar features, this one was unusually large and elaborate for a two-legged meat-eater, Clark and co-authors wrote.

Nobody knows its purpose, but it was probably some kind of display to other members of its own species, said Clark, co-leader of 2002 expedition that found the beast.

The researchers named the creature Guanlong wucaii, from the Chinese words for "crown" and "dragon," referring to the crest, and for "five colors," from the multi-hued badlands where the creature was found.

Because it preserves anatomical features from its ancestors that were lost in T. rex and other tyrannosaurs, the primitive beast helps scientists understand where tyrannosaurs fit in the evolutionary tree, said an expert not involved in the discovery.

"This is the best look so far at the ancestral condition from which the tyrant dinosaurs, T. rex and company, evolved," said the expert, Thomas Holtz Jr. of the University of Maryland.

Along with some other finds, the creature helps illustrate the sequence of anatomical changes that occurred along the way to the later, more specialized tyrannosaurs, said Philip Currie of the University of Alberta in Canada.

Ken Carpenter, curator of lower vertebrate paleontology at the Denver Museum of Nature and Science, said he tentatively accepts the creature as a tyrannosaur but isn't convinced of its age. It could be much younger, he said. Clark said that other data, not yet published, support the proposed age of 160 million years.

___

On the Net:

Nature: http://www.nature.com/nature

Background on tyrannosaurs:

http://www.ucmp.berkeley.edu/d.....ridae.html
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PostPosted: Wed Mar 01, 2006 3:08 pm    Post subject: The Biggest Carnivore: Dinosaur History Rewritten Reply with quote

The Biggest Carnivore: Dinosaur History Rewritten
By Robin Lloyd
Special to LiveScience
posted: 01 March 2006
08:49 am ET

The Age of Dinosaurs ended millions of years ago but paleontologists are still attempting to get a handle on the immense diversity and diverse immensity of these creatures.

Take the report last month that Spinosaurus is now officially the biggest carnivorous dinosaur known to science. This two-legged beast actually strode onto the fossil scene in 1915 when a specimen was described by German paleontologist Ernst Stromer. He figured this theropod (defined as a two-legged carnivore) was bigger than Tyrannosaurus rex, but the original Spinosaurus bones were destroyed by Allied bombs in 1944. So the T. rex reigned as the king size, carnivorous land beast for decades.

Then along came Giganotosaurus 11 years ago.

Now Cristiano Dal Sasso of the Civil Natural History Museum in Milan says Giganotosaurus has been dethroned based on estimates from a new Spinosaurus skull.


Full Article with images

http://livescience.com/animalw.....vores.html
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PostPosted: Mon Mar 06, 2006 4:18 pm    Post subject: Baby Triceratops Skull Suggest Reasons for Horns Reply with quote

Baby Triceratops Skull Suggest Reasons for Horns
By LiveScience Staff

posted: 06 March 2006
02:37 pm ET

A baby Triceratops skull suggests the impressive horns of the beast were for more than just attracting a mate.

The three-horned Triceratops dinosaur weighed up to 10 tons and had one of the largest skulls of any land animal on the planet.

Now the smallest skull of the species suggests what the horns were for.

"The baby Triceratops confirmed our argument that the horns and frill of the skull likely had another function other than sexual display or competition with rivals, which people have often argued, and allows us to propose that they were just as important for species recognition and visual communication in these animals," said paleontologist Mark Goodwin at the University of California at Berkeley.

The young one was about one year old and 3 feet long. As with many young animals, it had a short nose compared to the adults.

The skull is now on display at the university's Valley Life Sciences Building. Goodwin describes it in the March issue of the Journal of Vertebrate Paleontology and the university issued a statement on it today.

Triceratops horridus was a North American dinosaur, though relatives roamed China and Mongolia during the Cretaceous period, 144 million to 65 million years ago. An adult Triceratops could be nearly 10 feet tall and 26 feet long, with a bony frill around the head up to 7 feet across. Two 3-foot horns typically curved forward from the brow. A third horn rose from the nose above a narrow, horny beak.

The baby's skull, along with a few vertebrae, teeth and bony tendons, were discovered by amateur fossil hunter Harley Garbani in 1997 in Montana's Hell Creek Formation.

The surface of the skull shows grooves were blood vessels used to be, perhaps to nourish a fingernail-hard covering of keratin similar to the thicker layer that covers an adult skull. Such horny coverings are often brightly colored in birds, which are thought to be descendents of dinosaurs. That suggests Triceratops may have been colorful, too.

The two brow horns are straight and about an inch long in the baby.

The brain casing had not yet fused in the young beast.

"The baby skull shows us how the bones that make up the skull actually grew and fit together, because we see the sutures and sutural surfaces, which were completely obliterated in the adults," Goodwin said.
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PostPosted: Mon Mar 20, 2006 8:05 pm    Post subject: Streeeetch! Long-neck Dinosaur Sets New Standard Reply with quote

Streeeetch! Long-neck Dinosaur Sets New Standard
By Bjorn Carey
LiveScience Staff Writer
posted: 20 March 2006
02:02 pm ET

Scientists have identified a new dinosaur species that had one of the longest necks relative to body length ever measured.

A typical neck bone in this creature was about the size of two loaves of bread.

The species, Erketu ellisoni, belongs to the group of massive four-legged herbivorous dinosaurs called Sauropoda, the largest land animals ever to walk on Earth. This giant group also includes Brachiosaurus, Diplodocus, and the largest of them all, the 120-foot long Argentinasaurus.

E. ellisoni had an extremely elongated neck. A single neck vertebra measures nearly two feet long, longer than the same vertebrae of the much larger Diplodocus carnegii.

"If you compare the index of elongation—how long vertebrae are compared to how long or tall the dinosaur is—to Diplodocus carnegii, [E. ellisoni's] vertebrae are longer, but even more stretched out from front to back," said study co-author Dan Ksepka, a graduate student at Columbia University who studies at the American Museum of Natural History in New York City.

The discovery was announced today.

Based on the specimen's partial remains, researchers estimate the neck was more than 24 feet long all together. However, estimates of body size, based on limb bones and not including tail, indicate the body was probably about half as long as the neck. This gives E. ellisoni one of the longest necks relative to body size of all sauropods.

Researchers also recovered a chest plate, two lower leg bones, and a potato-sized ankle bone in Bor Guve in Mongolia's Gobi Desert in 2002. The bones were found among rocks deposited in a floodplain 120 million to 100 million years ago.

Museums and movies have long reconstructed sauropods in postures similar to a giraffe—with their heads held high, grazing hard-to-reach leaves. But based on how vertebrae fit together, recent studies and computer modeling suggest that these dinosaurs may actually have walked with their necks and heads held parallel to the ground.

"Based on what we know about other sauropods and what skeletal remains we do have, it looks like [E. ellisoni] had a similar posture," Ksepka told LiveScience.

That doesn't mean that they couldn't lift their heads, Ksepka said, just that this is how it probably was in a relaxed pose.

The giant vertebrae also shed light on how sauropods managed life with the burden of such long necks. The sides of the bones feature large concavities where air sacs would have existed, and scans reveal that the bones are not solid, but filled with numerous small pneumatic chambers that would reduce weight.

Also, unlike human vertebrae, the spines along the top of some vertebrae are split in two parallel tracks rather than one. This space may have been carved out for a ligament that helped support the neck.

"It's not acting to lift the head up, though," Ksepka said. "It's acting like a bungee cord to provide support to keep the neck held in horizontal position without having to fire muscles."

This track arose independently in several species of sauropods, but this is the first time it has been observed in a Titanosauria, a subgroup of Sauropoda of which E. ellisoni is a member.
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PostPosted: Thu Jun 08, 2006 11:05 am    Post subject: Dwarf Dinosaur Discovered Reply with quote

Dwarf Dinosaur Discovered

By Bjorn Carey
LiveScience Staff Writer
posted: 07 June 2006
01:00 pm ET



Scientists have unearthed what they consider to be a dwarf species of dinosaur. The beast was still bigger than a horse.

On a dig in northern Germany, researchers recovered bones from 11 individuals of a new dinosaur species. The specimens belonged to the dinosaur family Sauropoda, which includes some of the largest beasts ever to walk the planet. This giant group also includes Brachiosaurus, Diplodocus, and the largest of them all, the 120-foot long Argentinasaurus.


For the full article:

http://www.livescience.com/ani....._dino.html
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PostPosted: Tue Jul 11, 2006 10:29 am    Post subject: Big Dinosaurs Were Hot, Study Suggests Reply with quote

Big Dinosaurs Were Hot, Study Suggests

By Bjorn Carey
LiveScience Staff Writer
posted: 10 July 2006
08:06 pm ET



A new study helps answer a longstanding dinosaur mystery by revealing that the largest dinosaurs could likely maintain warm body temperatures while their smaller cousins were probably more similar to modern cold-blooded reptiles.

Scientists have debated the body temperature of dinos for years, mainly whether the beasts were cold-blooded ectotherms, like reptiles, or warm-blooded endotherms, like mammals and birds.


For the full article:

http://www.livescience.com/ani.....ature.html
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PostPosted: Mon Sep 25, 2006 7:37 pm    Post subject: Myth Busted: Dinosaur Not a Cannibal Reply with quote

Myth Busted: Dinosaur Not a Cannibal

By Ker Than
LiveScience Staff Writer
posted: 25 September 2006
01:00 pm ET



A dinosaur species long accused of cannibalism and infanticide is finally having the charges against it dropped and its reputation restored.

Researchers re-examining the anatomy of a Coelophysis fossil at the American Museum of Natural History (AMNH) found that bones in the rib-cage of the small upright dinosaur are not of its own kind, but of a primitive crocodile.

In a separate example, it was shown that the remains of a juvenile Coelophysis were actually located outside of another adult. The adult dinosaur probably crushed the juvenile when it died, the researchers say, and when the flesh decayed, the overlapping bones created the illusion that one dinosaur ate the other.

"Our research shows that the evidence for cannibalism in Coelophysis is non-existent," said study team member Sterling Nesbitt of the AMNH and Columbia University's Lamont-Doherty Earth Observatory in New York.

For the full article:

http://www.livescience.com/ani.....nibal.html
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PostPosted: Wed Dec 20, 2006 10:43 am    Post subject: Dinosaurs -- stones did not help with digestion Reply with quote

University of Bonn
20 December 2006

Dinosaurs -- stones did not help with digestion

Sauropods did not have a 'gastric mill.' How they processed their food without molars remains unclear
The giant dinosaurs had a problem. Many of them had narrow, pointed teeth, which were more suited to tearing off plants rather than chewing them. But how did they then grind their food? Until recently many researchers have assumed that they were helped by stones which they swallowed. In their muscular stomach these then acted as a kind of 'gastric mill'. But this assumption does not seem to be correct, as scientists at the universities of Bonn and Tübingen have now proved. Their research findings can be found in the current issue of the journal Proceedings of the Royal Society (doi:10.1098/rspb.2006.3763).

What do you do if you do not have good teeth, and food is hard to digest? Some herbivorous birds which have a toothless beak, such as ostriches, solve the problem with what is known as a gastric mill. Their muscular stomach is equipped with a layer of horn and contains stones which help to break up, crush and thereby also to digest food.

Giant dinosaurs from the Jurassic and Cretaceous period (200 million to 65 million years ago) such as Seismosaurus and Cedarosaurus must have had similar digestive problems. The animals, some of which weighed more than 30 tonnes, were the largest herbivores which have ever existed. Many of them had a very small head, in relation to the size of their body, and narrow, pointed teeth, which were more suited to tearing off plants rather than chewing them. At the same time, they had to digest enormous amounts of food for their rapid growth and the metabolism of their gigantic bodies. Smoothly polished stones, which were found in several cases at excavations involving skeletons of sauropods, are also interpreted as gastric stones.

However, Dr. Oliver Wings from the Institute of Earth Sciences at the University of Tübingen, and Dr. Martin Sander from the University of Bonn have shown that this cannot at least be a gastric mill such as birds, today's relatives of the dinosaurs possess. Among these the ostrich is the largest herbivore. For their investigations, the scientists therefore offered stones such as limestone, rose quartz and granite as food to ostriches on a German ostrich farm.

After the ostriches had been slaughtered, the scientists investigated the gastric stones. It became clear that they wore out quickly in the muscular stomach and were not polished. On the contrary, the surface of the stones, which had been partly smooth, became rough in the stomachs during the experiments. The mass of the stones then corresponded on average to one per cent of the body mass of the birds.

'Whereas occasionally stones were found together with sauropod skeletons, we don't think they are remains of a gastric mill such as occurs in birds,' Dr. Sander comments. In that kind of gastric mill the stones would have been very worn and would not have a smoothly polished surface. Apart from that, gastric stones are not discovered regularly at sauropod sites. When present, their mass is, in relation to the body size, much less than with birds. 'In comparing these we extrapolate over four orders of magnitude, from an ostrich weighing 89 kilograms to a sauropod weighing 50,000 kilograms. This may seem a bit daring. However, within birds the range of body weight and corresponding masses of gastric stones also spans four orders of magnitude, from the 17 gram robin to the ostrich,' says Oliver Wings, who moved from Bonn University to Tübingen only recently.

Yet what else were the dinosaurs' gastric stones used for? The researchers presume that they were accidentally eaten with their food or could have been swallowed on purpose to improve the intake of minerals. But if the stones did not help to crush vegetable food, the sauropods' digestive system must have used other methods, since the decomposition of large amounts of material which is difficult to digest requires the assistance of bacteria in the digestive system. The smaller the pieces are, the better they can break down the food. Possibly, the scientists conclude, the intestines of the sauropods were formed in such a way that the food was retained there for a very long time, in order to improve the digestive process.

There is another group of dinosaurs, however, whose remains of gastric stones can be linked up with a birdlike gastric mill, according to Oliver Wings' research. From these dinosaurs known as theropods today's birds developed. The gastric mill could therefore have developed in the ancestral line of birds.
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PostPosted: Wed Jan 31, 2007 7:51 am    Post subject: Europe's First Stegosaurus Discovered Reply with quote

Europe's First Stegosaurus Discovered

By Ker Than
LiveScience Staff Writer
posted: 31 January 2007
06:27 am ET

A Stegosaurus fossil has been discovered in Europe, marking the first time the famous plated dinosaur has been found outside of North America.

The find supports a widely accepted idea that the two continents were once connected by a series of temporary land bridges which surfaced when sea levels dipped, allowing dinosaurs to cross.

“Both coasts were very close and the basins between them could emerge occasionally,” said study leader Fernando Escaso of the University of Autonoma in Madrid, Spain.

During the first half of dinosaurs’ 185-million-year reign on Earth, all of the world’s continents were clumped together into one giant landmass called Pangaea. At the end of the Jurassic Period, about 150 million years ago, the supercontinent began slowly splintering: North America, Europe and Africa began to drift apart, and in the widening rift between them, the Atlantic Ocean was born.


For the full article:

http://www.livescience.com/ani.....aurus.html
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PostPosted: Thu Mar 08, 2007 9:35 am    Post subject: Dino Bones Reveal DNA Surprise Reply with quote

Dino Bones Reveal DNA Surprise

By Robin Lloyd
LiveScience Senior Editor
posted: 07 March 2007
01:04 pm ET

The distinction between birds and the dinosaurs from which they evolved is getting even murkier. The genomes (complete DNA sequences) of both groups are short, researchers now say.

Scientists used to think that relatively shorter genomes were associated with flight. Birds have short genomes compared to other vertebrates, or animals with backbones—the average bird genome length is a measly 1.45 billion base pairs. Bats also have short genomes—about 2.25 billion base pairs. Humans genomes are another billion base pairs longer. Also, flightless birds tend to have longer genomes than flying birds.

But the new finding by Chris Organ of Harvard University and his colleagues complicates this thinking and shows that the shorter genomes of birds originated in saurischian dinosaurs, the group of dinosaurs from which birds evolved and that includes Tyrannosaurus rex. So rather than being a characteristic of birds or flying animals, short genomes should be thought of as a characteristic of dinosaurs, including the killer theropod dinosaurs, he said.

For the full article:

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PostPosted: Fri Mar 23, 2007 2:22 pm    Post subject: Dinosaurs Dug Deep, Possibly to Survive Catastrophe Reply with quote

Dinosaurs Dug Deep, Possibly to Survive Catastrophe

By Charles Q. Choi
Special to LiveScience
posted: 23 March 2007
12:09 pm ET

An underground den of dinosaurs now reveals the first evidence that at least one species of “terrible lizards” could burrow.

The findings, detailed in the March 21 issue of the journal Proceedings of the Royal Society B, suggest dinosaurs could have endured extremes of heat or cold by finding shelter within dens of their own making. They also hint that such burrowing dinosaurs could have even survived the initial brunt of whatever eventually killed most of them off in the so-called K-T extinction some 65 million years ago.

The new dinosaur species is dubbed Oryctodromeus cubicularis, or “digging runner of the lair,” explained researcher David Varricchio, a paleontologist at Montana State University. The herbivore possessed a snout that could have shoveled away dirt, as well as large shoulder bones for powerful muscles and strong hips to support the body—all traits possibly evolved for digging.

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PostPosted: Fri Apr 13, 2007 9:52 am    Post subject: T. Rex Related to Chickens Reply with quote

T. Rex Related to Chickens

By Jeanna Bryner
LiveScience Staff Writer
posted: 12 April 2007
02:10 pm ET

An adolescent female Tyrannosaurus rex died 68 million years ago, but its bones still contain intact soft tissue, including the oldest preserved proteins ever found, scientists say.

And a comparison of the protein’s chemical structure to a slew of other species showed an evolutionary link between T. rex and chickens, bolstering the idea that birds evolved from dinosaurs.

The collagen proteins were found hidden inside the leg bone of the T. rex fossil, according to two studies published in the April 13 issue of the journal Science. Collagen is the main ingredient of connective tissue in animals and is found in cartilage, ligaments, tendons, hooves, bones and teeth. It yields gelatin and glue when boiled in water.

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PostPosted: Mon Apr 30, 2007 9:26 am    Post subject: How to look at dinosaur tracks Reply with quote

University of Chicago Press Journals
30 April 2007

How to look at dinosaur tracks

A new study appearing in the May issue of The Journal of Geology provides fascinating insight into the factors geologists must account for when examining dinosaur tracks. The authors studied a range of larger tracks from the family of dinosaurs that includes the T. Rex and the tridactyl, and provide a guide for interpreting the effects of many different types of erosion on these invaluable impressions.

“Well-preserved vertebrate tracks in the rock record can be an invaluable source of information about foot morphology, soft tissue distribution, and skin texture,” write Jesper Milàn (Geological Institute, University of Copenhagen) and David B. Loope (Department of Geosciences, University of Nebraska, Lincoln). “However, in most instances, the tracks are less than perfectly preserved, and sometimes they can be barely recognizable as tracks at all.”

With this in mind, Milàn and Loope sought to describe and categorize different levels of preservation. For example, dinosaur tracks may still exist as true tracks, that is, the original prints left in the ground by the dinosaur. True tracks preserve many of the anatomical details of the foot, such as number of digits and impressions of claws.

However, the true tracks may be filled with sediment or the original tracked surface may have eroded away. In the latter case, erosion may expose prominent layers of concentric circles extending from the former location of the true track. These “undertracks” reveal the squishing and displacement of sand when the heavy dinosaur took a step.

“The tracks and undertracks of large theropods found in the [Middle Jurassic] Entrada Sandstone at the studied locality come in a wide range of morphologies, mainly as a result of present-day erosion that has exposed the track-bearing surfaces at different depths,” the researchers explain. “[They] demonstrate that great care should be taken when describing fossil footprints that have been exposed to subaerial erosion, because the shape, dimensions, and general appearance of the footprint become seriously altered by erosion.”

Geologists also must account for whether the step was taken on a sloped surface or on a horizontal surface, and whether it was taken during dry season or wet season.

For example, estimating foot length from tracks can be inaccurate without these considerations – the more erosion that has occurred, the larger the apparent dimensions of the track. Applications of this apparently larger foot size derived from an undertrack may lead to calculations of higher estimated hip length, and, as the authors point out, may also lead to slower speed estimates.

###
One of the oldest journals in geology, The Journal of Geology has since 1893 promoted the systematic philosophical and fundamental study of geology. The Journal of Geology publishes research on geology, geophysics, geochemistry, sedimentology, geomorphology, petrology, plate tectonics, volcanology, structural geology, mineralogy, and planetary sciences.

Jesper Milàn and David B. Loope, “Preservation and Erosion of Theropod Tracks in Eolian Deposits: Examples from the Middle Jurassic Entrada Sandstone, Utah, U.S.A.” The Journal of Geology: 115, p. 375-386.
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PostPosted: Fri May 04, 2007 1:22 pm    Post subject: Huge Titanosaur Fossils Found Reply with quote

Huge Titanosaur Fossils Found

By The Associated Press

posted: 04 May 2007
03:48 pm ET

BRISBANE, Australia — Scientists unveiled bones from two 82-foot behemoths they said were the largest dinosaurs ever found in Australia.

Fossilized bones from the two titanosaurs were found in 2005 and 2006 by ranchers near the town of Eromanga, 600 miles west of the Queensland state capital, Brisbane.

They were put on display for the first time at the Queensland Museum on Thursday after a long period of excavation and scientific identification.

“These are the largest bones ever discovered in Australia,'' museum curator Scott Hocknull told reporters. The biggest of the bones — a humerus, from a foreleg — measures 5 feet long and weighs 220 pounds.

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PostPosted: Wed May 09, 2007 11:32 am    Post subject: How to Spot T. Rex Footprints Reply with quote

How to Spot T. Rex Footprints
By Charles Q. Choi, Special to LiveScience

posted: 09 May 2007 08:38 am ET

The largest predators to ever stride the earth-T. rex and its kin-often left indelible footprints with their massive steps, and some of their tracks are still evident millions of years after the dinosaurs perished.

In most cases, dinosaur footprints are less than ideally preserved, and many times are barely recognizable as tracks. Now a field guide of sorts amassing research on how such footprints can get eroded could help identify these tracks, no matter their state. This could help reveal details about dinosaur anatomy and locomotion otherwise lost to history.

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PostPosted: Mon May 21, 2007 8:26 pm    Post subject: T. Rex's Secret Weapon Discovered Reply with quote

T. Rex's Secret Weapon Discovered
By Jeanna Bryner, LiveScience Staff Writer

posted: 18 May 2007 12:49 pm ET

A paleo-bully of sorts, a Tyrannosaurus rex could chomp down on prey with the force needed to lift a semi-trailer, tearing apart a victim's bones. Now researchers have discovered the dino's secret weapon: it was hard-headed.

"Fused, arch-like nasal bones are a unique feature of tyrannosaurids," said lead scientist Eric Snively of the University of Alberta. "This adaptation, for instance, was keeping the T. rexes from breaking their own skull while breaking the bones of their prey."

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PostPosted: Thu May 24, 2007 11:34 am    Post subject: Tracks Reveal Dinosaurs Swam Reply with quote

Tracks Reveal Dinosaurs Swam
By Jeanna Bryner, LiveScience Staff Writer

posted: 24 May 2007 09:07 am ET

Newly discovered fossilized claw marks paint a picture of a carnivorous dinosaur pedaling its hind legs as it swam against a strong current and struggled to maintain a straight path.

The fossils, part of a 125 million-year-old trackway, are the most compelling evidence to date that some non-avian theropod dinosaurs could swim, scientists say in the June issue of the journal Geology.

A team led by Ruben Ezquerra of the Foundation Patrimonio Paleontológico spotted the 50-foot-long trackway of 12 consecutive S-shaped prints in La Virgen del Campo in La Rioja, Spain-a track site known for its abundance of non-aquatic dinosaur prints, too.

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PostPosted: Sat May 26, 2007 2:13 pm    Post subject: Stegosaurus Babies Made Tracks Reply with quote

Stegosaurus Babies Made Tracks
By Eric W. Bolin, Associated Press

posted: 25 May 2007 10:08 am ET

MORRISON, Colo. — Researcher Matt Mossbrucker believes four small dinosaur tracks found within sight of the skyscrapers of downtown Denver were made by two stegosaur babies, a find he says would be “incredibly rare.”

Some other researchers agree the tracks were left by stegosaur toddlers, but still others have their doubts.

Mossbrucker, director of the Morrison Natural History Museum, said the half-dollar-size tracks were discovered in the foothills just west of Denver last year, but it took time and digging for him to conclude they were made by stegosaur babies.

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PostPosted: Wed Jun 06, 2007 1:40 pm    Post subject: Terrible T. Rex Was a Slowpoke Reply with quote

Terrible T. Rex Was a Slowpoke
By LiveScience Staff

posted: 06 June 2007 09:17 am ET

T. rex was no slacker. But the popular image of a nimble predator turning on a dime and chasing down prey with lightning speed is fiction, new computer models show. The terrifying tyrannosaur was actually a slowpoke.

Previous studies have looked at the movements of birds, the direct descendents of dinosaurs, and fossilized footprints to judge how Tyrannosaurus rex would have moved.

To get a better estimate of the giant’s movement, the new study modeled a typical complete T. rex skeleton, which probably weighed between about 13,000 and 17,000 pounds, and estimated its center of mass and the inertia, or resistance to movement, that it would have had when the animal turned or pivoted.

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PostPosted: Sun Jun 10, 2007 2:38 pm    Post subject: Dinosaurs Died Agonizing Deaths Reply with quote

Dinosaurs Died Agonizing Deaths
By LiveScience Staff

posted: 09 June 2007 10:07 am ET

Fossilized dinosaurs often have wide-open mouths, heads thrown back and tails that curve toward the head. Paleontologists have long assumed the dinosaurs died in water and the currents drifted the bones into that position, or that rigor mortis or drying muscles, tendons and ligaments contorted the limbs.

"I'm reading this in the literature and thinking, 'This doesn't make any sense to me as a veterinarian,'" said Cynthia Marshall Faux, a veterinarian-turned-paleontologist at the Museum of the Rockies.

Faux and a colleague say brain damage and asphyxiation are the more likely culprits.

A classic example of the posture, which has puzzled paleontologists for ages, is the 150-million-year-old Archaeopteryx, the first-known example of a feathered dinosaur and the proposed link between dinosaurs and present-day birds.

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PostPosted: Thu Jun 14, 2007 9:22 am    Post subject: Huge Bird-Like Dinosaur Discovered Reply with quote

Huge Bird-Like Dinosaur Discovered
By Jeanna Bryner, LiveScience Staff Writer

posted: 13 June 2007 11:15 am ET

A gigantic bird-like dinosaur weighing as much as a car towered over its relatives about 70 million years ago, a new finding suggests.

The unearthed beaked dinosaur was not full-grown, yet it tipped the scales at more than 3,000 pounds. Paleontologists who discovered its remains estimate the behemoth was just 11 years old when it perished.

Chinese scientists unearthed the skeletal remains of the dinosaur, now named Gigantoraptor erlianensis, in the Erlian Basin of Inner Mongolia, China.

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PostPosted: Sat Jun 16, 2007 6:09 am    Post subject: Big and Birdlike: Chinese dinosaur was 3.5 meters tall Reply with quote

Week of June 16, 2007; Vol. 171, No. 24 , p. 371

Big and Birdlike: Chinese dinosaur was 3.5 meters tall
Sid Perkins

Paleontologists have unearthed the remains of an immense, fast-growing dinosaur whose body proportions don't match those predicted by the evolutionary trends that characterize its more diminutive kin.

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http://sciencenews.org/articles/20070616/fob1.asp
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