Did T. Rex Have Feathers?

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http://www.msnbc.msn.com/id/46954385/ns/technology_and_science-science

The discovery of a giant meat-eating dinosaur sporting a downy coat has some scientists reimagining the look of Tyrannosaurus rex.

With a killer jaw and sharp claws, T. rex has long been depicted in movies and popular culture as having scaly skin. But the discovery of an earlier relative suggests the king of dinosaurs may have had a softer side.

The evidence comes from the unearthing of a new tyrannosaur species in northeastern China that lived 60 million years before T. rex. The fossil record preserved remains of fluffy down, making it the largest feathered dinosaur ever found.

If a T. rex relative had feathers, why not T. rex? Scientists said the evidence is trending in that direction.

"People need to start changing their image of T. rex," said Luis Chiappe, director of the Dinosaur Institute at the Natural History Museum of Los Angeles County, who was not part of the discovery team.

Much smaller dinosaurs with primitive feathers have been excavated in recent years, but this is the first direct sign of a huge, shaggy dinosaur. Scientists have long debated whether gigantic dinosaurs lost their feathers the bigger they got or were just not as extensively covered.

The new tyrannosaur species, Yutyrannus huali, is described in Thursday's issue of the journal Nature. Its name is a blend of Latin and Mandarin, which translates to "beautiful feathered tyrant."

Most dinosaurs were vegetarian, research suggests

http://www.telegraph.co.uk/science/dinosaurs/8214257/Most-dinosaurs-were-vegetarian-research-suggests.html

Most dinosaurs were vegetarian, research suggests
Most dinosaurs were vegetarian rather than meat-eating beasts, research suggests.
Andy Bloxham
21 Dec 2010

While Tyrannosaurus Rex sums up the image of a dinosaur wreaking terror by ripping flesh with powerful jaws, many of its closest relatives were more content nibbling leaves.

A new study of the diet of 90 species of theropod dinosaurs challenged the conventional view that nearly all theropods hunted prey, especially those closest to the ancestors of birds.

Rather it showed that among the most bird-like dinosaurs known as coelurosaurs plant eating was a common way of life.

Their diet may have also helped them survive and exploit new environments becoming the most successful group of dinosaurs throughout the Cretaceous Period, 145-65 million years ago.

Dr Lindsay Zanno of the Chicago Field Museum said: "Most theropods are clearly adapted to a predatory lifestyle, but somewhere on the line to birds, predatory dinosaurs went soft."

Theropods are a group of bipedal dinosaurs colloquially known as "predatory" dinosaurs and include the iconic hunters Tyrannosaurus and Velociraptor.

Among theropod dinosaurs, all modern birds and several groups of their closest extinct relatives belong to a subgroup known as Coelurosauria.

Most were feathered and most intelligent dinosaurs and those with the smallest body sizes also belong to this group.

However researchers have been only left with fossilized bones and teeth to work with and so had to deduce their diets.

For example the bone-crunching teeth and jaws of Tyrannosaurus rex were the tools of a megapredator or that the tooth batteries of Triceratops were used for shearing plant material.

However many coelurosaurian dinosaurs have more ambiguous adaptations such as peg-like teeth at the front of the mouth or no teeth at all so determining their diet has been a challenge.

Dr Zanno added: "These oddball dinosaurs have been the subject of much speculation but until now, we have not had a reliable way to choose between competing theories as to what they ate."

But a small number of fossilized dinosaur dung, stomach contents, tooth marks, the presence of stones within the stomach that serve as a gastric mill for digesting vegetation have been found along with a number of species.

And two dinosaur species preserved locked in the throes of combat have been found to cast light on the mystery of what dinosaurs ate.

The researchers found almost two dozen anatomical features statistically linked to direct evidence of herbivory including a toothless beak.

"Once we linked certain adaptations with direct evidence of diet, we looked to see which other theropod species had the same traits. Then we could say who was likely a plant eater and who was not."

Applying their data on diet, the researchers found that 44 theropod species distributed across six major lineages were eating plants and that the ancestor to most feathered dinosaurs and modern birds had probably already lost its appetite for flesh alone.

Because plant eating was found to be so widespread in Coelurosauria, the hypercarnivorous habits of T. rex and other meat eating coelurosaurs like Velociraptor should be viewed "more as the exception than the rule."

Besides identifying diet, the researchers analyzed whether different groups of coelurosaurs followed the same evolutionary pathways toward an herbivorous diet.

They found that over time, species lost their flesh-rending teeth, developing strange tooth types such as peg, wedge, and leaf-shaped teeth, and ultimately, some lost most or all of their teeth altogether and replaced them with a bird-like beak.

The beaks then continued to evolve into a myriad of forms and help support a high degree of dietary diversity in modern birds.

One theory why they were so successful was that the break up of continents and origin of new habitat opened up new dietary niches for coelurosaurs to explore.

Dr Zanno said: "The ability to eat plant materials may have played a pivotal role in allowing coelurosaurian dinosaurs to achieve such remarkable species diversity.

"But more study is needed to understand what role dietary shifts may play in evolutionary processes."

Because ceolurosaurian dinosaurs include the closest extinct relatives of birds, understanding their biology is also extremely important to understanding how, why, and under what conditions birds evolved and first took flight.

"We don't know what drove the ancestors to birds to take flight," she says, "seeking food in the trees is just one of many possibilities."

Using statistical analysis to find correlations between physical traits and diet could offer a new window as to how evolution works.

"Being able to establish diet in extinct animals with confidence will allow us to start tackling even broader questions, such as whether animals tend to increase in body and diversity when they evolve herbivory."

The findings are published in the journal Proceedings of the National Academy of Sciences.

Tyrannosaurus Rex: the cannibal

http://www.telegraph.co.uk/science/dinosaurs/8066416/Tyrannosaurus-Rex-the-cannibal.html

Tyrannosaurus Rex: the cannibal
Tyrannosaurus Rex's reputation as a cold blooded killer just got worse – the prehistoric predators feasted on each other, scientists believe.
Richard Alleyne, Science Correspondent
15 Oct 2010

The seven tonne monsters, which at 13 feet tall and 40 feet long were the largest land predators to ever to stalk the earth, were cannibals, a new study has found.

Paleontologists noticed bite marks on the bones of the dinosaurs, and on examining the huge gouges realised T-Rex was the only carnivore large enough to have caused them.

Scientists are sure that the marks were caused by feeding rather than combat, although it is not clear whether the carcass was scavenged or devoured after a clash with another T-Rex 65 million years ago.

The winner may have eaten the loser, said Yale University researcher Dr Nick Longrich.

He said: "It is the first evidence of cannibalism but in a way it is not surprising. Modern big carnivores like lions and alligators do this all the time.

"It's a convenient way to take out the competition and get a bit of food at the same time. "

The marks seem to have been made after death, suggesting that the predator may have eaten the most accessible meat after the kill before returning to gnaw at the bones.

Dr Longrich said the find was an important clue into the eating habits of T-rex, whose name means tyrant lizard king and unlike today's large carnivores hunted alone rather than in packs.

He said: "These animals were some of the largest terrestrial carnivores of all time, and the way they approached eating was fundamentally different from modern species.

"There's a big mystery around what and how they ate, and this research helps to uncover one piece of the puzzle."

Dr Longrich made the breakthrough while looking through fossil collections for mammal tooth marks, and finding one bone, excavated in western America, with particular large gouges, reports journal PLoS ONE.

He said: "They're the kind of marks that any big carnivore could have made, but T. rex was the only big carnivore in western North America 65 million years ago."

It was only after establishing the bite marks were from a T-Rex that he realised the bone itself was also from the behemoth.

He turned his study to other T-Rex bones and found similar evidence on cannibalism.

He said: "It's surprising how frequent it appears to have been."

Only one other dinosaur species, Majungatholus, is known to have been a cannibal, but Dr Longrich believes further study could show the practice was more widespread than is currently believed.

Biggest Dinosaurs Grew Huge by Not Chewing

http://news.nationalgeographic.com/news/2008/10/081009-dinosaur-big.html

Biggest Dinosaurs Grew Huge by Not Chewing Their Food
Kate Ravilious
for National Geographic News
October 9, 2008

Dinosaurs known as sauropods—the largest land animals that ever lived—grew huge and were an evolutionary success in part because they didn't bother to chew their food, new research suggests.

Sauropods weighed up to 88 tons (80 metric tons)—ten times more than an African elephant—and measured as high as 23 feet (7 meters).

The group of dinosaurs, which included the brachiosaurus and diplodocus, loomed over the animal kingdom for more than 140 million years until the late Cretaceous period, 65 million years ago. (See a brachiosaurus herd.)

Scientists think the animals evolved to be so large to discourage big predators, like Tyrannosaurus rex, from eating them. But how they maintained such massive body sizes has remained mysterious.

The herbivores, or plant-eaters, had hardly any teeth and are thought to have swallowed their food whole—an entire bush in one gulp, for example. They browsed large areas, barely moving and consuming vast quantities in short periods of time.

So they needed long necks to reach food high in trees and a huge gut to process and break down their unchewed meals, said Martin Sander, a palaeontologist at the University of Bonn in Germany and co-author of the study, published tomorrow in the journal Science.

"You can only have this long neck if you don't chew your food, otherwise your head would be full of teeth and too heavy to support," he said.

Paul Upchurch, an expert on sauropods from University College London, said that "most palaeontologists agree that feeding is the key to understanding sauropod gigantism."

Survival Strategies

To outgrow their predators, sauropods didn't just need lots of food. They also needed to develop fast, so they could attain their full size before being eaten, experts said.

Sauropod bones show that they did indeed grow swiftly. A 22-pound (10-kilogram) hatchling could become a 220,000-pound (100,000-kilogram) grown-up in about 20 to 30 years—quick by dinosaur time.

"This tells us that they must have been warm-blooded and had a high metabolic rate compared to cold-blooded creatures," said the University of Bonn's Sander.

Like all dinosaurs, sauropods laid nestfuls of eggs. By producing so many young at a time, "a population could recover quickly, even after a big catastrophe," Sander said.

Large modern mammals, such as elephants, give birth to far fewer offspring, raising their chances of extinction should a disaster occur.

So why don't we see gigantic elephants and crocodiles roaming around today?

Experts think that reptiles, such as crocodiles, still maintain the egg-laying advantage, but their cold blood prevents them from growing fast enough to reach a great size.

Mammals have warm blood, but can't grow as big as sauropods due to their slow reproductive strategy and the need to chew their food.

Huge Flying Reptiles Ate Dinosaurs

http://www.livescience.com/animals/080527-giant-reptile.html

Huge Flying Reptiles Ate Dinosaurs
By Jeanna Bryner, Senior Writer
27 May 2008

A group of flying reptiles called Quetzalcoatlus may have strolled along a fern prairie eating baby dinosaurs for lunch.

With a name like T. rex, you'd expect to be safe from even the fiercest paleo-bullies. Turns out, ancient, flying reptiles could have snacked on Tyrannosaurus Rex babies and other landlubbing runts of the dinosaur world.

A new study reveals a group of flying reptiles that lived during the Age of Dinosaurs some 230 million to 65 million years ago did not catch prey in flight, but rather stalked them on land.

Until now, paleontologists pictured the so-called "winged lizards" or pterosaurs as skim-feeders. In this vision, the creatures would have flown over lakes and oceans grabbing fish from the water's surface, much as gulls do today.

The new findings, detailed this week online in the journal PLoS ONE, don't ground the animals totally.

"In our hypothesis, flight is primarily a locomotive method," said co-researcher Mark Witton of the University of Portsmouth in England. "They're just using it to get from point A to point B. We think the majority of their lives, when they're feeding and reproducing, that's all being done on the ground rather than in the air."

To uncover these feeding habits, Witton and Portsmouth colleague Darren Naish analyzed fossils of a group of toothless pterosaurs called azhdarchids, which are much larger on average than other pterosaurs. For example, one of the largest azhdarchids, Quetzalcoatlus, weighed about 550 pounds (250 kilograms) with a wingspan of more than 30 feet (10 meters) and a height comparable to a giraffe.

Witton and Naish learned that more than 50 percent of the azhdarchid fossils had been found inland. Other skeletal features, including long hind limbs and a stiff neck, also didn't fit with a mud-prober or skim-feeder.

"All the details of their anatomy, and the environment their fossils are found in, show that they made their living by walking around, reaching down to grab and pick up animals and other prey," Naish said.

A skim-feeder, such as a gull, trawls its lower jaw through the water, eventually smacking into a fish or shrimp and pulling it from the water. "Regardless of what they hit, the impact force drives the head and neck underneath the body and into the water, thus requiring a hugely flexible neck," Witton said.

This is the case with gulls and pelicans (which are considered plunge divers), but azhdarchid's neck, despite potentially reaching nearly 10 feet (3 meters) in length, was super stiff. "Whatever these animals were doing, it had to involve minimal neck action," Witton said.

Their tiny feet also ruled out wading in the water or probing the soft mud for food. "Some of these animals are absolutely enormous," Witton told LiveScience. "If you go wading out into this soft mud, and you weigh a quarter of a ton, and you've got these dinky little feet, you're going to just sink in."

The reptile's head also was pretty lengthy, up to 10 feet (3 meters). So Witton said an azhdarchid would only have to dip its head part way to the ground, enough for the tip of its jaws to touch down, to hunt and feed on terrestrial prey. Back before they went extinct 65 million years ago during the event that also killed off non-avian dinosaurs, these pterosaurs could lunch on animals ranging from small bird-like Velicoraptors to T. rex babies to amphibians.

Tests Confirm T. Rex Kinship With Birds

http://www.nytimes.com/2008/04/25/science/25dino.html

April 25, 2008
Tests Confirm T. Rex Kinship With Birds
By JOHN NOBLE WILFORD

In the first analysis of proteins extracted from dinosaur bones, scientists say they have established more firmly than ever that the closest living relatives of the mighty predator Tyrannosaurus rex are modern birds.

The research, being published Friday in the journal Science, yielded the first molecular data confirming the widely held hypothesis of a close dinosaur-bird ancestry, the American scientific team reported. The link was previously suggested by anatomical similarities.

In fact, the scientists said, T. rex shared more of its genetic makeup with ostriches and chickens than with living reptiles, like alligators. On this basis, the research team has redrawn the family tree of major vertebrate groups, assigning the dinosaur a new place in evolutionary relationships.
Similar molecular tests on tissues from the extinct mastodon confirmed its close genetic link to the elephant, as had been suspected from skeletal affinities.

“Our results at the genetic level basically agree with what has been seen in skeletal data,” John M. Asara of Harvard said in a telephone interview. “There is more than a 90 percent probability that the grouping of T. rex with living birds is real.”

Dr. Asara and Lewis C. Cantley, both of Beth Israel Deaconess Medical Center and Harvard Medical School, processed the proteins from tissue recovered deep in bones of a 68 million-year-old T. rex excavated in 2003 by John R. Horner of Montana State University. Mary H. Schweitzer of North Carolina State University discovered the preserved soft tissues in the bones.
For the molecular study, Dr. Asara and Chris L. Organ, a researcher in evolutionary biology at Harvard, compared the dinosaur protein with similar protein from several dozen species of modern birds, reptiles and other animals.

Dr. Organ was the lead author of the journal report, which concluded that the molecular tests confirmed the prediction that extinct dinosaurs “would show a higher degree of similarity with birds than with other extant vertebrates.” The researchers said they planned to extend their investigations to include comparisons of T. rex protein with more species of birds, reptiles and other dinosaurs.

Dinosaur paleontologists were not surprised by the findings. An accumulation of fossil evidence in recent years had given them increasing confidence in their contention that birds descended from certain dinosaurs.

'Monster' Arctic Reptile Remains Found

http://apnews.myway.com/article/20071204/D8TAUFR80.html

'Monster' Arctic Reptile Remains Found
Dec 4, 2007

OSLO, Norway (AP) - Remains of a bus-sized prehistoric "monster" reptile found on a remote Arctic island may be a new species never before recorded by science, researchers said Tuesday.

Initial excavation of a site on the Svalbard islands in August yielded the remains, teeth, skull fragments and vertebrae of a reptile estimated to measure nearly 40 feet long, said Joern Harald Hurum of the University of Oslo.

"It seems the monster is a new species," he told The Associated Press.

The reptile appears be the same species as another sea predator whose remains were found nearby on Svalbard last year. His team described those 150-million-year-old remains as belonging to a short-necked plesiosaur measuring more than 30 feet - "as long as a bus ... with teeth larger than cucumbers."

The short-necked plesiosaur was a voracious reptile often compared to the Tyrannosaurus rex of the oceans.

Mark Evans, a plesiosaur expert at the Leicester City Museums in Britain, said he not know enough about the Norwegian find to comment on it specifically. But he said new types of the sea reptiles are being found regularly.

"We are regularly seeing new species of plesiosaurs popping up - in a way because, in the past 10 or 15 years, there has been what we call a renaissance in plesiosaur research," Evans said by telephone.

Hurum said the team had only managed to excavate a 3-meter (yard) area of the find. The Norwegian-led team plans to present more detailed findings early next year, and return to Svalbard, 300 miles north of Norway's mainland, to excavate further next year.
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On the Net:

http://www.nhm.uio.no/pliosaurus/index.html

T-rex versus Beckham? Sorry, David, you're lunch

http://news.yahoo.com/s/nm/20070822/ts_nm/dinosaur_speed_dc

T-rex versus Beckham? Sorry, David, you're lunch
By Michael Kahn
Tue Aug 21, 2007

The smallest dinosaur could reach speeds of nearly 40 mph (64 kph) and even the lumbering Tyrannosaurus rex would have been able to outrun most modern-day sportsmen, according to research published on Wednesday.

Scientists using computer models calculated the top speeds for five meat-eating dinosaurs in a study they say can also illustrate how animals cope with climate change and extinction.

The velociraptor, whose speed and ferocity was highlighted in the film "Jurassic Park," reached 24 mph while the T-rex could muster speeds of up to 18 mph, the study published in the Royal Society's Biological Sciences showed.

"Our research, which used the minimum leg-muscle mass T-rex required for movement, suggests that while not incredibly fast, this carnivore was certainly capable of running and would have little difficulty in chasing down footballer David Beckham, for instance," said Phil Manning, a paleontologist at the University of Manchester, who worked on the study.

The smallest dinosaur -- the Compsognathus -- could run nearly 40 mph, about 5 mph faster than the computer's estimate for the fastest living animal on two legs, the ostrich.

A top human sprinter can reach a speed of about 25 mph.

The researchers used a computer model to calculate the running speeds of the five dinosaurs that varied in size from the 3-kg (6.6 pound) Compsognathus to a six-tonne Tyrannosaurus.

They fed information about the skeletal and muscular structure of the dinosaurs into the computer and ran a simulation tens of millions of times to see how fast the animals moved, said William Sellers, a zoologist at the University of Manchester, who led the study.

They checked their method by inputting data of a 70-kg human with the muscle and bone structure of a professional sportsman and found the computer accurately spat out a top running speed just behind T-rex's pace.

"People have estimated speeds before but they have always been indirect estimates and hard to verify," Sellers said. "What we found is they were all perfectly capable of running."

Looking at how these ancient animals lived and died out is also important in trying to predict how modern day species may cope with future climate change, Sellers added.

This study helps to build a biological picture that scientists can use to better understand how dinosaurs adapted to changes in the weather just before they went extinct some 65 million years ago, he said.

"Knowing how these animals coped over the past millions of years will give us clues to what is going to happen over the next thousand years," he said. "That is why there has been more recent interest in biology of these animals."