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A thick rain of volcanic ash sends a rat-size mammal, Gobiconodon zofiae, and three Dilong paradoxus dinosaurs fleeing for their lives in this artist's depiction. To delete this file, click the file name with your mouse, then right-click and scroll down the menu to the "delete" option. To remove the photo permanently from the desktop, locate the photo on the hard drive and drag it to the trash. See how science has changed the art of dinosaur illustrationa€”from the addition of feathers to, as of today, the discovery of dinosaur pigment. In 1996 the scientific world was stunned to learn that a fossil dinosaur with feathers had been found in China.
The fossil of Sinosauropteryx revealed in 1996, above, was so well preserved that hairlike structures were apparent all over its body.
A detail of the hairlike structures in the fossil of Sinosauropteryx gives the impression that they were soft and downlike. This illustration of an adult Oviraptor feeding its young, which appeared in National Geographic magazine in 1996, was prepared just before the discovery of feathers on dinosaurs. As more and more evidence piled up to support the idea that dinosaurs were not only related to birds but had feathers, artists and scientists began to feel more comfortable creating scenes including feathery dinosaurs like the hatchling Tyrannosaurus rex in this 1999 National Geographic magazine illustration.There were two main reasons why National Geographic commissioned this art despite the fact that, as of 1999, no tyrannosaur had been found with feathersa€”that would come later, in 2004. The first fossil of Archaeopteryx was a lone feather found fossilized in a limestone quarry in Germany in 1860 (left). The discovery of melanosomes in fossil birds and dinosaurs, announced in January 2010, may help determine some colors in prehistoric feathersa€”such as the the speculative blacks and browns on this 1996 model of the feathered dinosaur Caudipteryx zoui.But not all feather color is produced by melanosomes. This feathery scene created in the late 2000s shows what look like giant turkeys facing off against a menacing meat-eater.
Harmless snakes can strike their prey just as quickly as venomous vipersa€”putting a legendary Wild West tale to rest. Peek at Jupiter through binoculars and you should also see its icy moon Europa, thought to host a global ocean that may support life. Before Chicxulub, people had some odd theories about what caused the demise of the dinos, including low libido and caterpillars run amok.
With its rock-hard horns, shieldlike head plate, and massive torso, Triceratops horridus—"three-horned face"—must have been an intimidating presence in the late Cretaceous period. A bizarre gallery of Mesozoic monsters prompts John Updike to ask: What has evolution wrought? A newly identified species of spiky-headed dinosaur that roamed Canada 78 million years ago is the oldest known large, horned reptile ever discovered in North America. Like its more famous cousin Triceratopsa€”which lived 15 million years later, during the dinosaurs' last daysa€”Xenoceratops had long spearlike horns thrusting from its brow and a shieldlike frill extending back from its skull.
The new dinosaur is known from fragments of fossilized skull and horn found in Alberta, Canada. Measuring approximately 20 feet (6 meters) long and more than 2 tons, Xenoceratops was average-size for a horned dinosaura€”African elephant-size Triceratops was half again as large. Living alongside Xenoceratops would have been predators related to Tyrannosaurus rex as well as duck-billed dinosaurs and ankylosaursa€”dinosaurs resembling giant armadillos with big club tails. In the late Cretaceous period, they all would have known a very different Alberta from the current, cool Canadian province, Ryan said. Today, the area around Foremost is prairie country, he said, and inhabited by the modern analog of horned dinosaurs: cattle. Xenoceratops' flamboyant frill reveals that horned dinosaurs evolved intricate cranial ornaments very early in their lineagea€”adornments that got only more elaborate with time, scientists say. Moreover, it appears that Xenoceratops and Triceratops' different scientific subfamiliesa€”Centrosaurinae and Chasmosaurinae, respectivelya€”didn't look all that different from one another early in their evolution. With the discovery of the burials at Gobero, striking evidence is coming to light about the Kiffian and Tenerian cultures that lived in the now hyperarid Tenere desert.

On October 13, 2000, a small team of paleontologists led by Paul Sereno of the University of Chicago clambered out of three battered Land Rovers, filled their water bottles, and scattered on foot across the toffee-colored sands of the Tenere desert in northern Niger.
Sereno, a National Geographic Society explorer-in-residence and one of the world's most prolific dinosaur hunters, had led his first expedition into the Tenere five years earlier, after negotiating agreements with both the leader of a Tuareg rebel force and the Niger Ministry of Defense, allowing him safe passage to explore its fossil-rich deposits. Mike Hettwer, a photographer accompanying the team, headed off by himself toward a trio of small dunes. New insights about the asteroid thought to have killed off the dinosaurs suggest it may have just been the final blow, and that the reptiles were already suffering from a finicky climate prompted by volcanic eruptions long before the meteorite struck. The research, detailed in the February 8 issue of the journal Science, adds to the ongoing scientific debate over what exactly killed off the dinosaurs. That debate, which once revolved around the question of whether the culprit was an asteroid or volcano-induced climate changes, has evolved to consider the possibility that perhaps multiple environmental factors were involved. Using a high-precision dating technique on tektitesa€”pebble-sized rocks formed during meteorite impactsa€”from Haiti that were created during the event, the team concluded that the impact occurred 66,038,000 years agoa€”slightly later than previously thought. When error limits are taken into account, the new date is the same as the date of the extinction, the team says, making the events simultaneous.
Renne said the new findings should lay to rest any remaining doubts about whether an asteroid was a factor in the dinosaurs' demise.
That is not to say, however, that the asteroida€”which carved out the so-called Chicxulub cratera€”was the sole cause of the dinosaurs' extinction. Evidence now suggests massive volcanic eruptions in India that predated the asteroid strike also played a part, triggering climate changes that were already killing off some dinosaur groups. The idea that volcanism was responsible for the dinosaurs' demise actually predates the impact theory, and it fits well with what is known about Earth's other mass extinction events.
But in the 1980s, father-son team Luis and Walter Alvarez, a physicist and planetary scientist, respectively, presented a bold new theory. After discovering that a layer of clay that's found throughout the world and that coincided with the end of the Cretaceous period is enriched in iridiuma€”an element rare on Earth but common in space rocksa€”they proposed that a meteorite wiped out the dinosaurs. The crater's size indicated that whatever created it was roughly 6 miles (10 kilometers) in diameter. The once-abandoned volcanism theory has seen a revival of sorts in recent years, however, as a result of fresh insights about a period of sustained ancient volcanic activity in India and the discovery that dinosaur diversity may have already been declining before the asteroid strike. Renne belongs to the camp that thinks a series of volcanic eruptions in India that produced ancient lava flows known as the Deccan Traps caused dramatic climate variations, including long cold snaps, that may have already been culling the dinosaurs before the asteroid struck. The new hybrid theory still has some major questions it must answer, however, like precisely how much the Indian volcanic eruptions affected the dinosaurs. Knowing the timing of the eruptions is important, Pälike added, because if they were happening close to the end of the Cretaceous, it's more likely they played a role in the dinosaurs' extinction than if most of the eruptions happened two million years before. Pinning down the cause of the dinosaurs' extinction isn't just of academic interest, said Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History at the University of Florida. Whatever your interest, you'll be entertained and educated with our collection of best-selling DVDs.
Based on the features of a 125-million-year-old fossil preserved by such ashfalls, these tyrannosaurs exhibit a downy covering of protofeathers, the first found among their family.
These showed up as dark areas, particularly along the back and tail.Researchers assumed that the whole animal had been covered in these short filaments. It was only later that many specimens of the crow-size Archaeopteryx were found with fossilized bones and preserved impressions of feathers, such as this full-body fossil (right) found nearby in 1861.Many very birdlike feathered dinosaurs have since been discovered in the 131- to 120-million-year-old Jehol Group sediments of China since 1996, when Sinosauropteryx was reported. Some colorsa€”such as the pink in flamingo feathers and the bright yellow of canariesa€”are produced by the food animals eat.So far, there's no proven way of detecting signs of those types of colors in fossils.
It also shows how far paleoartists have come in their depictions of birdlike dinosaurs.The turkey-like creature is actually the giraffe-size oviraptor, Gigantoraptor, whose discovery was announced in 2007. But this giant was an herbivore, preying only on the vegetation of western North America.Fossil evidence shows that Triceratops was about 30 feet (9 meters) long and 10 feet (3 meters) tall and weighed 4 to 6 tons.

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Ryan and his team recently found 78-million-year-old bones during a dig, and that led them to search the collection of the Canadian Museum of Nature in Ottawa for other fossils from the same time period. The museum fossils dated to the same period as Ryan's team's bones, and appeared to belong to the same unidentified species of dinosaur. The Tenere, on the southern flank of the Sahara, easily ranks among the most desolate landscapes on Earth. That initial foray was followed by others, and each time his team emerged from the desert with the remains of exotic species, including Nigersaurus, a 500-toothed plant-eating dinosaur, and Sarcosuchus, an extinct crocodilian the size of a city bus. The evolutionary precursors of true feathers, protofeathers were hairlike and probably developed for insulation. Many paleontologists suggested the structures were protofeathers, the evolutionary precursors to the type of feathers seen commonly on birds today.Some researchers weren't convinced and suggested that the structures were the fossilized remains of collagen that was originally inside the dinosaur's body, not outside, as feathers would be.
Rex Cousin Had Feathers.")First, tyrannosaurs were evolutionarily more "modern" than Sinosauropteryxa€”so if Sinosauropteryx had feathers, so could T. These new specimens have raised important questions about the origins of feathers, birds, and flight.With the January 2010 announcement that melanosomes have been found in fossil feathers, many museum drawers around the world will be opened to check for fossilsa€”perhaps including Archaeopteryx fossilsa€”that might have fossilized pigment. In the future, however, that may be possible as efforts to study the chemical compositions of fossils continue.
Stout limbs supported Triceratops's girth, but it was unlikely the dinosaur could move very quickly.Like a modern-day rhinoceros, Triceratops probably spent much of its time grazing on plant matter.
As soon as I saw them, I recognized it as being different from every other horned dinosaur," said Ryan, who heads the vertebrate paleontology division of the Cleveland Museum of Natural History in Ohio.
The Tuareg, turbaned nomads who for centuries have ruled this barren realm, refer to it as a "desert within a desert"—a California-size ocean of sand and rock, where a single massive dune might stretch a hundred miles, and the combination of 120-degree heat and inexorable winds can wick the water from a human body in less than a day. The 2000 expedition, however, was his most ambitious—three months scouring a 300-mile arc of the Tenere, ending near Agadez, a medieval caravan town on the western lip of the desert. Future studies may also reveal the colors of other melanin-containing coverings, such as skin and hair, and perhaps even the color of eyes. This is a reflection of the fact that long, filamentous feathers are being found on larger and larger dinosaurs, such as Beipiaosaurus (see picture), suggesting that feathers had other functions in nonflying dinosaurs than keeping the little ones warm.Even though the color is guesswork, illustrations like this, showing very birdlike, colorful dinosaurs, are now mainstream. It used its beaklike mouth and powerful jaws lined with rows of sharp cheek teeth to shred and grind cycads, ferns, and other low-lying vegetation.Triceratops's head was its most imposing feature.
The harsh conditions, combined with intermittent conflict between the Tuareg and the Niger government, have kept the region largely unexplored. Already, his team members had excavated 20 tons of dinosaur bones and other prehistoric animals.
Second, since most of the feathered dinosaurs that had been found thus far were small, the function of feathers may have been to keep small dinosaurs, like baby tyrannosaurs, warm.
It used its horns—a short one above its mouth and two long ones above its eyes—to charge predators, such as T.
It may have acted as a radiator, helping Triceratops regulate its body temperature.This ceratopsian, or horned dinosaur, was one of the last dinosaurs in the late Cretaceous period.

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