Dinosaur Skin

[Mighty_Emperor]

Rare find: A dinosaur preserved with its skin

Inside Grand Staircase: A group of visitors gets a peek at a fossilized skull protruding from a ridge

By Mark Havnes
The Salt Lake Tribune



CEDAR CITY - The hadrosaur was a big and plentiful dinosaur that once browsed on the lush vegetation on the coastal plain covering southern Utah.

On Saturday, 75 million years later, a handful of people had the opportunity to see the skull of one of the dinosaurs protruding from a ridge in the Grand Staircase-Escalante National Monument. Alan Titus explained the significance of the sight.

"It's a fossilized bag of bones with the guts rotted out," said Titus, a paleontologist for the monument who discovered the fossilized skull in September 2003.

He said the find is significant because of the preservation of the skin, a rare find.

"With skin, we can start putting the animal together," said Titus as the group examined the dimpled texture of what was once the dinosaur's flesh.

After the giant reptile died and before it was torn to pieces by meat-eating dinosaurs, the creature was buried in a river bed. Sand filled its cavity after the softer tissue had decomposed, said Titus. The sand made an impression of the the skin from the inside, then solidified.

Titus said that three weeks ago a near-perfect skull of a similar hadrosaur, found earlier at the monument, was delivered to the Utah Museum of Natural History at the University of Utah.

He said the hadrosaur weighed about three tons, had a length of 25 feet with a skull about 3 1/2 feet long. It is unknown if the skull is still attached to a body, extending deeper into the ridge or if it became separated from the body.

The skull will soon be removed from its rock tomb and sent to a laboratory and prepared for further study by using precision tools to peel away the rock layers surrounding it. Removing the skull and preparing it could take two years.

While discoveries of hadrosaurs have been made in Montana, Titus said the ones found in the monument suggest the possibility that dinosaurs thought to live only in northern areas might have mixed with those living only in southern regions.

"The whole age of dinosaurs is laid out before you here," said Titus, gazing out across the monument, studded with pinyon pine and juniper trees instead of the redwoods, cyprus magnolias and ferns the hadrosaurs once gorged on.

Rita Halfast of Page, Ariz., who visited the skull site Saturday with husband Tim and 8-year-old son, Nicholas, said she has always been interested in dinosaurs.

"They're fascinating," she said. "It was neat to see the fossil of one outside and not in a museum, though its also great what museums do."

"It was cool," said Kayla Shenfeld, 12. "I'm glad I came out here."

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The tour was limited to 70 people. Another tour will be held Oct. 14.

To make reservations, call 435-644-4680.

http://www.sltrib.com/utah/ci_2419563

If anyone is in the area then I'd recommend they go along - it sounds great.

 

[Mighty_Emperor]

This may have some bearing on the finds:

Dinosaurs' 'bulletproof' armour revealed

15:57 16 November 04



An in-depth study of dinosaur armour has revealed an unexpected new level of strength, with some plates having a weave of fibres resembling today’s bulletproof fabrics. The likely strength of such plates makes the dinosaurs studied - ankylosaurs - perhaps the best-protected creatures to have ever stalked the Earth.

Ankylosaurs were massive herbivores that grew up to 10 metres in length during the late Jurassic and Cretaceous periods. The coin-sized plates sported by the ankylosaurs fully covered their back, neck, head and even protected their eyes.

“Their whole lifestyle was connected with this armoured living, which improved defence against predators. Other dinosaurs would have to be really hungry to attack an ankylosaur,” says lead researcher Torsten Scheyer at the University of Bonn, Germany.

Like other armoured animals - such as crocodiles and turtles - the bonelike plates were actually derived from skin and called osteoderms. While scientists have been fascinated with dinosaur armour for years, few studies have looked at the microstructure of their constituent minerals and proteins.


Collagen fibres

Scheyer, along with his doctoral supervisor Martin Sander, took samples of body plates from each of the three groups of ankylosaur species: polocanthids, thought to be the earliest ankylosaurs, nodosaurids and ankylosaurids. For comparison, armour plates from a stegosaur species and an ancient crocodile were also examined.

The researchers viewed thin sections of each plate with polarised light to highlight the mineralised traces left by bone and by fibres of collagen. Collagen is the tough protein that anchors armour plates to skin and also provides a framework on which the plates can grow.

Compared to stegosaurus or crocodile plates, the polocanthids had extra collagen fibres that may have stabilised the edges of individual plates. But in nodosaurids - which also had plates between 2 and 5 centimetres thick, the pattern of collagen fibres was highly organised in three dimensions.

They had a sets of structural fibres running parallel and perpendicular to the surface, and then further sets at 45° to each of these axes, providing strength in all directions. The fibres of the bulletproof fabric Kevlar are similarly arranged.

This type of arrangement is very strong and helps prevent bone from cracking, says John Currey at York University, UK - an expert in bone structure and mechanics. But he notes that assessing the actual strength of fossilised bone solely from their design is very difficult.


Crushing forces

Ankylosaurids had thinner plates, just 0.5 to 1.0 cm thick, but the undersides were hollowed out, creating a dome shape which may have added strength. But, in contrast to the nodosaurids, the collagen fibres were randomly arranged.

Scheyer and Sander conclude that ankylosaur species evolved progressively better armour plates to withstand the great crushing forces applied by the hungry jaws of its predators.

But Kenneth Carpenter, an armoured dinosaur expert at the Denver Museum of Natural History, US, remains unconvinced by their conclusions. Not all ankylosaurid plates are thin and not all nodosaurid plates are thick, he says.

He adds that the orientation of collagen in a plate is determined largely by its position on the skin, and Scheyer and Sander used plates whose original location on the dinosaurs’ bodies were not known.

However, John Rensberger, who studies the structure of dinosaur bones at the University of Washington in Seattle, US, says the evolution of increasingly strong armour fits with the story of ankylosaurs, who became increasingly massive and slow moving as their amour grew to completely cover their bodies.

“More primitive relatives of ankylosaurs have osteoderms, though not enough to cover their body entirely. But these were longer limbed, faster moving dinosaurs," he says. "There’s probably a co-evolution of the ankylosaurs, acquiring better armour at the expense of their speed.”

http://www.newscientist.com/news/news.jsp?id=ns99996674

 

[punychicken]

Another Utah find

A new species of dinosaur found in Utah has been called one of the weirdest ones ever and may point to how later creatures transformed into herbivores .

Found en masse in a Utah bone yard by a black market fossil dealer (who, incidentally has served 5 months in jail and paid a $15,000 fine for his dealings), the 125-million-year-old fossils are from Falcarius Utahensis (not to be confused with Faldrunkus Kentuckiensis).

Scientists say that though Falcarius may have eaten meat, its teeth and belly show the first signs of a dietary shift to vegetarianism.

"We can see definitive features of eating plants and know its descendents were much more full-time plant-eaters," James Kirkland, a paleontologist at the Utah Geological Survey in Salt Lake City said.

It is also suspected that the creature smelled of Patchouli and often wore hemp necklaces.

Covered in "hairlike" feathers, Falcarius measured 13 feet long and stood at 4.5 feet tall, walking on two legs.

Images here

First noticed by a black market fossil dealer, a new species found in a Utah boneyard may be a missing link in dinosaurs' trend toward vegetarianism. (See pictures of the new dinosaur.)

The 125-million-year-old fossils, from the dinosaur Falcarius utahensis, were discovered in a graveyard of hundreds, if not thousands, of individuals. Though it may have eaten meat, Falcarius's teeth and guts show the first signs of the species's change toward a leafy, green diet, said James Kirkland, a paleontologist at the Utah Geological Survey in Salt Lake City.

"We can see definitive features of eating plants and know its descendents were much more full-time plant-eaters," Kirkland said.

The newly discovered creature was likely cloaked in hairlike feathers and walked on two legs. Adults measured about 13 feet (4 meters) long, head to tail. They stood about 4.5 feet (1.4 meters) tall and had sharp, curved, 4-inch-long (10-centimeter-long) claws.

Kirkland and his colleagues from the University of Utah in Salt Lake City and the George Washington University in Washington, D.C. report the discovery in tomorrow's issue of the science journal Nature.

Bizarre Dinosaur

Falcarius was a member of the therizinosaurs. These feathered dinosaurs with birdlike hips are considered among the weirdest ever discovered.

Until recently, paleontologists argued over where the beasts fit on the evolutionary tree. At first, they were considered giant sea turtles, and then for years they were thought to be long-necked sauropod dinosaurs.

"In the last decade or so we've come to understand that therizinosaurs evolved from a raptorlike group of dinosaurs," said Lindsay Zanno, a graduate student in geology at the University of Utah and a co-author of the new study.

Falcarius, Zanno added, is the most primitive therizinosaur yet discovered and unequivocally demonstrates that the group evolved from Velociraptor-like ancestors.

Velociraptor was the fleet-footed, meat-eating dinosaur popularized in the movie Jurassic Park. The new dinosaur, Falcarius, did not descend directly from Velociraptor. Rather, Kirkland said, they are both descendants of a yet undiscovered common ancestor.

Going Veggie

Paleontologists believe the first dinosaur was a small-bodied, lightly built, fleet-footed predator.

Early on in dinosaur evolution, two major groups shifted to plant-based diets. But the fossil record of how dinosaurs went vegetarian, until now, was scant. Also, the plant-eaters' relationship to their meat-eating ancestors was unknown.

Thomas Holtz is a paleontologist at the University of Maryland in College Park. He said the Falcarius fossils are a clearer window into the shift from meat eating to plant eating than is available for equivalent transitions within other dinosaur groups. Prior to the Falcarius discovery, the likely intermediate forms between meat eaters and plant eaters "are either not yet discovered or are very fragmentary and so not recognized as such," Holtz said. That's what makes Falcarius so rare.

The Falcarius fossils show this transition in action among a group of dinosaurs, the birdlike meat-eating dinosaurs of the late Cretaceous period (about 140 million years ago). The finding allows paleontologists insight into long-nagging questions of evolution.

"If you're going to take a Velociraptor-type dinosaur and make a large-bodied, lumbering, bizarre-looking plant eater, what is it you need to do? What parts of the body need to change and how?" Zanno said.

Among the evidence for a dietary transition are teeth that look like tiny birch or elm leaves, a shape good for shredding plant material and shared with all other plant-eating dinosaurs, Kirkland said. In addition, the pelvis bone is expanded toward the side, a sign consistent with the larger gut size required to digest leafy greens.

"To digest plants is more difficult than to digest meat," Kirkland said. "Plant eaters have big digestive systems to process plant material."

Later therizinosaurs, Zanno said, had shorter tails that balanced their more upright posture for eating leaves off trees. They also had shorter legs that better supported their heavier frames and shoulder joints that allowed the arms to reach branches above the head.

But why go vegetarian? Kirkland said paleontologists can only speculate. But the dietary shift represented by Falcarius coincides with the appearance of the first flowering plants in the fossil record, she said.

Origin Rethink

Paleontologists working in China and Mongolia have been excavating therizinosaurs for about 50 years, accounting for a dozen species. Then in the late 1990s Kirkland, with Douglas Wolfe of Arizona's Mesa Southwest Museum, discovered the first recognized therizinosaur in North America, a species named Nothronychus.

Nothronychus, which was found in New Mexico, was dated to about 90 million years ago—significantly younger than the oldest therizinosaurs from Asia. Paleontologists reasoned that the group originated in Asia and used a land bridge between Alaska and Siberia to populate North America.

Falcarius, however, is 125 million years old, as old as Beipiaosaurus, the oldest known therizinosaur from Asia, which was preserved with feathers. According to Zanno, Falcarius is also more primitive than Beipiaosaurus. Also, some evidence suggests that 125 million years ago the land bridge with Alaska did not exist.

"We have to change our thinking," Zanno said. "It's possible [that therizinosaurs] may have evolved in North America and spread through Europe to Asia."

According to Kirkland, "anywhere in the whole Northern Hemisphere is up for grabs, and Europe is clearly the migratory route versus Alaska. People have a hard time remembering Alaska didn't exist" 125 million years ago.

Holtz agreed that this discovery suggests that early therizinosaurs migrated through Europe instead of over the land bridge between Alaska and Siberia. "I would suspect that Falcarius, or a dinosaur very similar to it, might one day be found in England," he said.

Fossil Trove

Kirkland and colleagues have excavated more than 1,700 Falcarius fossils at a previously overlooked, 2-acre (0.8-hectare) site at the base of the Cedar Mountain rock formation in east central Utah.

The site was discovered by a fossil hunter who was selling the bones illegally on the black market. After he discovered parts of Falcarius's distinctive neck, he realized he had something important and turned over the site to paleontologists for further research.

"We're very fortunate he came forward. We've all benefited from that," Kirkland said. "But he did spend five months in jail and paid a [U.S.] $15,000 fine. He may be the first person to ever go to jail for fossil theft on public land."

A second mass mortality site was discovered in the area by Celina and Marina Saurez, twins who are geology graduate students at Temple University in Philadelphia. The pair believes both sites are associated with a spring.

Kirkland said several explanations could explain the mass mortality at the springs, including drought, toxic gases, or botulinum (a bacterial toxin). The dinosaurs congregated in large numbers at the springs, at least periodically.

Regardless of how the dinosaurs died, Zanno, the University of Utah graduate student, said the site—which contains the bones of babies, juveniles, and adults—will likely be the best place for therizinosaur research for centuries to come.

"We'll be able to do really cool stuff, like determine how fast the animals grew, see at what age they reached maturity. Are there physical differences between babies and adults, differences between males and females? How much variation is there in the species," she said. "These are future research questions."