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Title: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:15:27 am
Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
December 22, 2009

Large, "lost," or simply unusual, a bevy of prehistoric beasts were brought to life in National Geographic News's most popular paleontology stories of the year.

      10. Biggest Trilobite Sea Beasts Found ... in Swarms

The "remarkable," yard-long, horseshoe crab-like arthropods roamed in swarms of up to a thousand animals, a May study suggests.

Top ten dinosaurs and fossil discoveries picture         9. "Lost World" of Dinosaurs Survived Mass Extinction?

An isolated group of dinosaurs may have outlived their doomed relatives by as much as half a million years, an April study suggested.

Top ten dinosaurs and fossil discoveries picture         8. A Third of Dinosaur Species Never Existed?

Young dinosaurs weren't Mini-Me versions of their parents, evidence presented in October suggests—meaning that up to a third of dinosaur species may be misidentified.

Top ten dinosaurs and fossil discoveries picture         7. Tiny "T. Rex" Found —150-Pound Species Came First

No heavier than a small man, Raptorex was Mini-Me to T. rex's dinosaur Dr. Evil. But in this case, the tiny gave rise to the titanic, researchers said in September.
• See pictures

Top ten dinosaurs and fossil discoveries picture         6. Five "Oddball" Crocs Discovered, Including Dinosaur-Eater

A "saber-toothed cat in armor" and a pancake-shaped predator are among five strange, dinosaur-era crocodile cousins discovered in the Sahara, archaeologists announced in November. Meet BoarCroc, PancakeCroc, DuckCroc, RatCroc, and DogCroc.
• See pictures

Top ten dinosaurs and fossil discoveries picture         5. AUSTRALIA DINOSAUR PICTURES: 3 New Species Found

Fossils of a ferocious predator and two giant plant-eaters, named for an Aussie poet and his creations, have been unearthed in the outback, paleontologists announced in July.

Top ten dinosaurs and fossil discoveries picture         4. NEW FOSSIL PHOTOS: "Graceful Weasel," Jewel Bug, More

A long-legged mammal, a sharp-toothed rodent, and an iridescent beetle are among the more than 6,500 Eocene-epoch fossils unearthed in Germany's Messel Pit, scientists announced in August.
   

Top ten discoveries picture         3. Biggest Snake Discovered; Was Longer Than a Bus
The 60-million-year-old reptile was also heavier than a car, scientists said in February, adding that the fossil could shed light on climate change.
• See pictures

Top ten discoveries picture         2. Oldest Skeleton of Human Ancestor Found
There was never a chimp-like missing link between humans and today's apes, according to an October fossil-skeleton study that could rewrite human evolutionary history. Said one scientist, "It changes everything."
• See pictures

Top ten discoveries picture         1. "Missing Link" Found: Fossil Connects Humans, Lemurs?
The 47-million-year-old, exceptionally preserved primate fossil "Ida," unveiled on May 20, was hailed by some as a major discovery in human evolution.

The publicity frenzy made National Geographic News's brief coverage our most viewed page of the year—and inspired a backlash as some experts, including one here at Nat Geo HQ, suggested Ida was more media event than milestone.

http://news.nationalgeographic.com/news/2009/12/091222-top-ten-dinosaurs-2009-fossils.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:20:46 am
PHOTO: Biggest Trilobite Sea Beasts Found ... in Swarms

(http://news.nationalgeographic.com/news/2009/05/images/090511-giant-trilobites-swarms-picture_big.jpg)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:21:21 am
May 11, 2009—Talk about ruining a good beach day.

Swarms of up to a thousand giant trilobites—extinct marine arthropods such as this 35-inch-long (90-centimeter-long) fossil specimen—roamed shallow prehistoric seas, new fossils show.

The 465-million-year-old fossils, found recently in northern Portugal, are of the largest trilobites ever discovered.

The trilobites may have clustered to mate and molt—shedding old exoskeletons as new ones grew in—as well as avoid predators, scientists say.

The benefits of swarming may explain why these distant relatives of horseshoe crabs were among the most widespread arthropods of the Paleozoic era (542 to 251 million years ago).

(Related: "Horseshoe Crabs Remain Mysteries to Biologists.")

Even so, finding complete specimens bigger than 12 inches (30 centimeters) is rare—making the new find "remarkable," the study authors write in a recent edition of the journal Geology.

The critters lived at high latitudes near Gondwana—a huge southern supercontinent—and close to the South Pole during the Ordovician period (map of Earth during the Ordovician period).

This oxygen-rich, cold-water habitat may have contributed to these trilobites' gigantic sizes, the authors added.

But repeated, sudden, "lethal" influxes of oxygen-starved water may have led to the newfound trilobites' demise millions of years ago.

—Christine Dell'Amore

Photograph courtesy Artur Sá, Geological Society of America

http://news.nationalgeographic.com/news/2009/05/090511-giant-trilobites-swarms-picture.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:22:16 am
"Lost World" of Dinosaurs Survived Mass Extinction?
Brian Handwerk
for National Geographic News

May 1, 2009

An isolated group of dinosaurs somehow survived the catastrophic event that wiped out most of their kind some 65.5 million years ago, a new study suggests.

Dinosaurs of this "lost world," in a remote region of the U.S. West, may have outlived their doomed relatives by as much as half a million years, according to James Fassett, an emeritus scientist with the U.S. Geological Survey in Santa Fe, New Mexico.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:22:41 am
Fassett, who has argued for years that some dinosaurs survived the mass extinction, based his latest work on fossils from the San Juan Basin in what is now Colorado and New Mexico.

There, the bones of hadrosaurs, tyrannosaurs, anklyosaurs, and several other species were found together in a sandstone formation that dates to the Paleocene epoch—the time period after the so-called Cretaceous-Tertiary (K-T) extinction event, which is thought to have killed off the dinosaurs.

As with his past research, Fassett's latest find is likely to continue sparking controversy among paleontologists.

"Every few years someone claims to have [found] Paleocene 'surviving' dinosaurs," said Hans-Dieter Sues, associate director for research and collections at the Smithsonian Institution's National Museum of Natural History.

But so far, such fossils have eventually turned out to be older remains.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:23:02 am
"Unequivocal Evidence"

In his new study, appearing in the April 2009 issue of the journal Palaeontologia Electronica, Fassett argues that a single hadrosaur fossil helps prove that the San Juan dinos really are from the Paleocene.

After previous "survivor" finds, it was determined that the dinosaurs in question, initially entombed in sand or mud, had their bones exposed again later by natural forces such as river erosion.

The bones were then redeposited in younger rock layers, making them appear to belong to an earlier era.

But paleontologists found a concentration of 34 bones from a single hadrosaur in the San Juan Basin sandstone.

http://news.nationalgeographic.com/news/2009/05/090501-dinosaur-lost-world.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:24:11 am
"That's unequivocal evidence I think," Fassett said. River-washed bones would be widely scattered and also show signs of wear and tear—unlike the current fossils, some of which he describes as "pristine."

Working with colleagues at the USGS in Denver, Fassett also examined the concentrations of uranium and rare-earth metals in the fossil bones.

"I thought if we could determine the trace-element compositions of the bones, we might discover that the [older] Cretaceous bones had a different chemical fingerprint than the [younger Paleocene] bones do," he said, "and indeed that turned out to be the case."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:24:29 am
No Reason Why Not

It's not known why some species, including crocodiles and birds, survived the K-T event while many others did not. The answer could be tied to what exactly caused the mass extinction.

The popular theory is that a killer asteroid struck the Yucatán Peninsula, although experts have argued for massive volcanism, disease, climate change, or some combination of factors.

(Related: "'Dinosaur Killer' Asteroid Only One Part of New Quadruple Whammy Theory.")

Fassett, who supports the asteroid-strike theory, said he can't explain why dinosaurs may have survived longer in some areas but not others.

"One guess is that the survivors lived in the northernmost parts of North America, at the greatest distance from the impact site, and then migrated south," he said.

"But that doesn't explain why [dinosaurs that lived later] haven't been found elsewhere. We don't have an answer for that."

Despite his caution, the Smithsonian's Sues said that the idea of Paleocene dinosaurs can't yet be dismissed.

"There is no a priori reason that dinosaurs could not have survived in some places," he wrote in an email to National Geographic News.

"Indeed, other than in the [U.S.] western interior and in Europe, we have as yet no concrete evidence when dinosaurs vanished."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:24:47 am
http://news.nationalgeographic.com/news/2009/05/090501-dinosaur-lost-world_2.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:25:15 am
(http://news.nationalgeographic.com/news/bigphotos/images/090501-dinosaur-lost-world_big.jpg)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:25:22 am
(http://news.nationalgeographic.com/news/bigphotos/images/090501-dinosaur-lost-world_big.jpg)

An isolated group of dinosaurs somehow survived the catastrophic event that wiped out most of their kind some 65.5 million years ago, an April 2009 study suggests. Above, an asteroid slams into Earth in an artist's conception of the event that is the basis for the leading theory for how the dinosaurs died.

Illustration by Don Davis/NASA


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:26:49 am
A Third of Dinosaur Species Never Existed?
Brian Handwerk
for National Geographic News
October 9, 2009


ON TV Dinosaurs Decoded, airs Sunday, October 11 at 9 p.m. ET/PT on the National Geographic Channel. Preview Dinosaurs Decoded >>

Many dinosaurs may be facing a new kind of extinction—a controversial theory suggests as many as a third of all known dinosaur species never existed in the first place.

That's because young dinosaurs didn't look like Mini-Me versions of their parents, according to new analyses by paleontologists Mark Goodwin, University of California, Berkeley, and Jack Horner, of Montana State University.

Instead, like birds and some other living animals, the juveniles went through dramatic physical changes during adulthood.

This means many fossils of young dinosaurs, including T. rex relatives, have been misidentified as unique species, the researchers argue.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:27:14 am
How T. Rex Became a Terror

The lean and graceful Nanotyrannus is one strong example. Thought to be a smaller relative of T. rex, the supposed species is now considered by many experts to be based on a misidentified fossil of a juvenile T. rex.

The purported Nanotyrannus fossils have the look of a teenage T. rex, Horner said in the new documentary. That's because T. rex's skull changed dramatically as it grew, he said.

The skull morphed from an elongated shape to the more familiar, short snout and jaw, which could take in large quantities of food.

But the smoking gun, Horner said, was the discovery of a dinosaur between the size of an adult T. rex and Nanotyrannus.

Nanotyrannus—actually a young T. rex in Horner's view—had 17 lower-jaw teeth, and an adult T. rex had 12.

The midsize dinosaur had 14 lower-jaw teeth—suggesting that it was also a young T. rex, and that tyrannosaurs gradually traded their smaller, blade-like teeth for fewer bone-crushing grinders in adulthood.

http://news.nationalgeographic.com/news/2009/10/091009-dinosaur-species-never-existed.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:28:20 am
Triceratops Transformation

The paleontologists also amassed a large collection of Triceratops fossils, which had died in various stages of life, from eastern Montana's Hell Creek formation from the late Cretaceous epoch (145.5 to 65.5 million years ago).

The dinosaur skulls, which ranged from dinner plate-size to human-size, came from a range of animals.

When the paleontologists studied the skulls, they found that the youngest animals' tiny, straight horns changed as they got older: Juveniles' horns actually curved backward, whereas adult horns pointed forward.

The animal's distinctive neck frill also changed—the triangular spiked bones surrounding the frill in juveniles became flattened and lengthened into a bony fan-like shield.

"In this ten-year project we were able to collect a very good growth series that no one had ever seen before, and see this transformation that occurs," Goodwin said.

"We could document the extreme changes that occur with growth, [like] the direction that the horns are pointing."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:29:06 am
Birds of a Feather

Clues to why dinosaurs underwent such dramatic physical changes may be found in their closest living relatives—birds experts say.

(Related: "New Feathered Dinosaur Found; Adds to Bird-Dino Theory.")

Hornbills, for example, don't sport their distinctive helmet-like head casque (see hornbill picture) until they are about three-quarters grown.

Like deer antlers, the casque helps other animals discern between mature adults and juveniles.

In the same way, dinosaurs' changing appearances might have also promoted visual communication.

For example head knobs or horns, likely paired with color variations, may have created unmistakable visual displays that made sure members of a species recognized one another.

They may also have identified dinosaurs as male or female and marked them as mate-seeking breeders or juveniles in need of protection.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:29:33 am
Exaggerated Conclusion?

Hans-Dieter Sues, a paleontologist at the National Museum of Natural History in Washington, D.C, said that scientists discovered in the 1970s that some duck-billed dinosaur species were in fact animals in different stages of maturity—representing a smaller number of species.

Sues, who was not involved in the new research, agrees that some dinosaur species from the late Cretaceous may prove to be juveniles of other species.

"Many dinosaurs—just like many present-day vertebrates—changed a lot in their appearance as they grew up," he said.

But "some of [these] conclusions are controversial," Sues cautioned, adding that the idea that up to a third of all species may be reclassified is an exaggeration.

In fact, Sues suspects that a second wave of dinosaur extinction is unlikely—unless, that is, fossil hunters hit the jackpot.

"Testing such hypotheses is difficult," he said, because "it requires more fossil material than is currently available."

http://news.nationalgeographic.com/news/2009/10/091009-dinosaur-species-never-existed_2.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:30:10 am
(http://news.nationalgeographic.com/news/bigphotos/images/091009-dinosaur-species-never-existed_big.jpg)

Many fossils of young dinosaurs, including T. rex relatives (above, a computer-generated image of a young T. rex), have been misidentified as unique species, paleontologists said in October 2009.

That means up to a third of all dinosaur species may have never existed, experts say.

Photograph © NGC


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:32:30 am
Tiny "T. Rex" Found -- 150-Pound Species Came First
Rebecca Caroll
for National Geographic News
September 17, 2009


If dinosaur evolution were an Austin Powers movie, T. rex would be Dr. Evil. And today scientists unveiled Mini-Me.

But in this case, it was the tiny terror that gave rise to the larger, more infamous relation.

Raptorex kriegsteini, described this week in the journal Science, likely lived about 125 million years ago, during the Cretaceous period.

That's almost twice as far back as the mighty Tyrannosaurus rex, which first arose about 85 million years ago, according to study leader Paul Sereno of the University of Chicago.

Raptorex has all the main characteristics of its larger descendants such as T. rex—big head, nipping teeth, stubby arms, fast legs—but packed into a 9-foot (3-meter) frame.

This T. rex design in miniature "reveals a spectacular carnivore strategy," according to Sereno, a National Geographic Society explorer-in-residence. (The National Geographic Society owns National Geographic News.)

(Read National Geographic magazine editor Chris Sloan's take on Raptorex.)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:33:02 am
Tiny T. rex "Evolutionarily Staggering"

The 150-pound (70-kilogram) Raptorex "was running things down, dispatching them with its powerful jaws, and clutching them with its two-fingered hands"—the same hunting strategy that apparently worked for 6-ton T. rex, Sereno said.

"That's the pretty evolutionarily staggering thing," he added. Raptorex is T. rex, but "scaled up, almost without change, a hundred times."

The find runs counter to previous theories, which had said that T. rex's stumpy arms were a relatively recent evolutionary development. As tyrannosaurs got larger, their arms simply didn't scale up fast enough, and the limbs eventually became small in relation to the dinosaurs' oversized bodies, the older theories say.

It's still thought, however, that T. rex's earlier ancestors—even before Raptorex—had relatively long arms.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:33:32 am
T. rex-style Arms Not a Liability

The new dinosaur is "a very significant find" for understanding the evolution of tyrannosaurs, said paleontologist Thomas Holtz of the University of Maryland.

"We didn't know where and when in the history of the tyrannosaurs this arm-shortening occurred," said Holtz, who was not part of the study.

"Now the question is going to be, What were they doing [with those small arms]?" Holtz said. "There's not much of a reach," he added, speculating that the tyrannosaurs grabbed prey first with their jaws and then used their arms to help hold onto their quarry.

Study leader Sereno noted that it can be hard for people to appreciate the trade-offs that evolution inevitably entails.

"It would seem to a human that forelimbs are so useful, that only when you got to the size of a tyrannosaur and you could frighten everybody with a growl could you get rid of [forearms]," he said.

"But this common sense type of thinking almost never works with evolution," Sereno said. In the tyrannosaurs, for instance, "long, heavy forelimbs are a significant burden and would seriously curtail agility in the hunt."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:34:01 am
Smuggled T. rex Ancestor Heading Home

The new findings are based on a nearly complete Chinese dinosaur skeleton, which was excavated in secret, smuggled into the United States, and sold at auction to private collector Henry Kriegstein.

Sereno said he convinced Kriegstein to donate the fossil back to science.

Although the exact location the dinosaur came from will never be known, the excavated block containing the dinosaur's skeleton also included fish bones and clamshells that link it to Northern China's Yixian fossil formation.

Raptorex kriegsteini, named after the collector's father, an Auschwitz survivor, will eventually be shipped back to Northern China, where it will be displayed in a museum in Hohhot, the capital of China's Inner Mongolia region.

"Fossils like these should be protected from smugglers, or there's a chance they could disappear forever," Sereno said.

Until that day comes, Sereno hopes the story of this fossil can serve as a model for saving—and learning from—smuggled dinosaurs.

"I think everybody involved with this Raptorex is a winner here," he said.

http://news.nationalgeographic.com/news/2009/09/090917-tiny-t-rex-dinosaur-raptorex.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:35:04 am
(http://news.nationalgeographic.com/news/bigphotos/images/090917-tiny-t-rex-dinosaur-raptorex_big.jpg)

Newfound Raptorex kriegsteini (illustrated above) resembled T. rex in nearly every way, except size, scientists announced in September 2009.

The new dinosaur species lived millions of years before its infamous descendant, and Raptorex's discovery suggests that tyrannosaurs' stumpy arms evolved later than previously thought.

Illustration by Todd Marshall via Science


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:36:38 am
5 "Oddball" Crocs Discovered, Including Dinosaur-Eater
Christine Dell'Amore
National Geographic News
November 19, 2009


ON TV When Crocs Ate Dinosaurs airs Saturday, November 21, at 9 p.m. ET/PT on the National Geographic Channel. Preview Crocs >>

A "saber-toothed cat in armor" and a pancake-shaped predator are among the strange crocodile cousins whose bones have been found beneath the windswept dunes of the Sahara, archaeologists say. (See pictures of BoarCroc, PancakeCroc, DuckCroc, RatCroc, and DogCroc.)

The diverse menagerie of reptiles ruled Gondwana—a landmass that later broke up into the southern continents—about a hundred million years ago, during the Cretaceous period. (See a prehistoric time line.)

"There's an entire croc world brewing in Africa that we really had only an inkling about before," said Paul Sereno, a paleontologist at the University of Chicago and leader of a new study.

"We knew about SuperCroc, the titan of all crocs, but we didn't have quite an idea of what existed in the shadows of the Cretaceous," he said.

Ancient crocodile cousins—called crocodilyforms—were not widespread in the Northern Hemisphere. But the south blossomed with bizarre riffs on the croc theme, added Sereno, also a National Geographic explorer-in-residence.

(The National Geographic Society owns National Geographic News.)

The team found three new species, nicknamed PancakeCroc, BoarCroc, and RatCroc, as well as new skeletons of the previously named DuckCroc and DogCroc. (Meet the strange crocs of the Sahara.)

"There's more to a croc than meets the eye of a living person," Sereno said. "We have crocs here [in what was once Gondwana] that ate plants and galloped and ate dinosaurs and were flat as a board."



Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:37:04 am
Dino-Era Crocs Were "Real Oddballs"

Sereno and colleagues have been scouring the harsh deserts of northern Africa since 2000 for evidence of a "lost world" of crocodilian ancestors.

Crocodilians are a living group that includes crocodiles, alligators, caimans, and more. (See alligator and crocodile pictures.)

Each ancient species evolved unique adaptations to reign over its own corner of the lush, river-carved plains of present-day Niger and Morocco, the study says.

For instance, the rodent-like RatCroc had buckteeth for rooting through the ground after tubers or simple animals.

The flat-bodied PancakeCroc was the "ultimate sit-and-wait predator," Sereno said. The animal would lie motionless and "wait for something stupid" to swim into its rail-thin, 3-foot-long (0.9-meter-long) jaws, which were lined with rows of spiky teeth.

DuckCroc had a long, smooth, sensitive nose to poke through vegetation as well as hook-shaped teeth to snag frogs and small fish in shallow water.

And the plant-eating DogCroc had lanky legs that meant it was likely spry enough to run into the water if threatened.

By far the mightiest of the lot, BoarCroc was a 20-foot-long (6.1-meter-long) "saber-toothed cat in armor" that ate dinosaurs for dinner.

Three sets of fangs—so long they jutted above and below the jaw when shut—handily sliced meat, while a snout reinforced with bonelike armor boosted the animal's ramming power.

"Gondwana had lots of real oddballs," said Hans Dieter-Sues, a paleontologist at the National Museum of Natural History in Washington, D.C., who was not involved in the research.

"For somebody who has studied a lot of fossil crocodilyforms, I'm fascinated by these creatures," Sues said.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:37:39 am
Croc Survivors

Skeletal analysis reveals that many of the Gondwana crocs were surprisingly limber, and some may have been able to gallop like modern saltwater crocodiles in Australia, said study leader Sereno, who has studied crocodile movement.

That crocodilian ancestors could run and swim with equal dexterity may have given them a leg-up on escaping predators—and extinction, Sereno added.

Some ancient crocs must have survived the mass extinction event that wiped out the dinosaurs about 65 million years ago. Being nimble on land and in water suggests the crocodile cousins may have taken refuge from environmental catastrophe in bodies of fresh water, where modern crocodilians still thrive, said Sereno, whose study appears today in the journal ZooKeys.

(Related: "'Lost World' of Dinosaurs Survived Mass Extinction?")

Christopher Brochu, a paleontologist at the University of Iowa, said that it's hard to tell if the ancient crocs really galloped.

Only a small number of modern-day crocodilians gallop, so it's possible the gait evolved among true crocodilians, said Brochu, who was not involved in the study.

"We need to be cautious," he said, "when extending behavior seen in a subgroup of crocodilians to more distant relatives."

He added the new species "are truly beautiful animals" that "really are going to be critical in understanding how the group was so diverse and dominant in the southern continents."

No matter how the ancient crocs moved, there's no denying that some of their traits—passed down via evolution—have helped crocodilyforms as a whole outmaneuver extinction, Sereno said.

"They were a really successful group—they are survivors."

http://news.nationalgeographic.com/news/2009/11/091119-dinosaurs-crocodiles-missions.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Ambrosia on December 24, 2009, 04:40:26 am
(http://news.nationalgeographic.com/news/bigphotos/images/091119-dinosaurs-crocodiles-missions_big.jpg)

BoarCroc (pictured in an artist's illustration) was a 20-foot-long (6.1-meter-long) "saber-toothed cat in armor" that ate dinosaurs for dinner.

The creature is among five ancient crocodile cousins discovered beneath the windswept dunes of the Sahara, archaeologists said in November 2009.

Illustration courtesy © NGT


http://news.nationalgeographic.com/news/2009/12/091222-top-ten-dinosaurs-2009-fossils.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:20:36 am
AUSTRALIA DINOSAUR PICTURES: Three New Species Found

(http://news.nationalgeographic.com/news/2009/07/photogalleries/australia-new-dinosaur-pictures/images/primary/090706-01-new-dinosaurs-matilda_big.jpg)

July 6, 2009--Meet Matilda, or Diamantinasaurus matildae (above, in an artist's depiction), one of two giant, plant-eating dinosaur species recently discovered in Australia.

The fossilized creature, which measures almost 60 feet (18 meters) long, was unearthed in the northeastern outback town of Winton, Queensland, in 2006. A third new species, a carnivorous dinosaur dubbed Banjo, was also found at the site. (Watch a video about Banjo's discovery.)

The dinosaurs were named after famed Australian poet Banjo Paterson and characters from his works.

(Related: "New Dinosaur May Link S. American, Aussie Dinos.")

The 98-million-year-old Matilda is the first new sauropod to be described in Australia in 75 years, said team member Scott Hocknull, a paleontologist and senior curator of geosciences at Queensland Museum in Brisbane.

The fossils, described recently in the journal PLoS One, were unveiled at the Australian Age of Dinosaurs Museum of Natural History in Winton on July 3, 2009.

--Carolyn Barry in Sydney, Australia
—Images courtesy Travis R. Tischler, Australian Age of Dinosaurs

http://news.nationalgeographic.com/news/2009/07/photogalleries/australia-new-dinosaur-pictures/


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:23:51 am
(http://news.nationalgeographic.com/news/2009/07/photogalleries/australia-new-dinosaur-pictures/images/primary/090706-02-new-dinosaur-teeth-banjo_big.jpg)

The ferocious-looking carnivore Australovenator wintonensis (above, in an artist's impression) is one of three new dinosaurs recently unearthed in the Australian outback town of Winton.

The 16.5-foot-long (5-meter-long), 6.5-foot-tall (2-meter-tall) meat-eater is the most complete theropod—a group of two-legged dinos related to birds—ever found in Australia and maybe even in the world, Hocknull said in July 2009.

Nicknamed Banjo, the velociraptor-like dinosaur had three slashing claws on both hands and larger arms than its cousin, Tyrannosaurus rex.
—Image courtesy Travis R. Tischler, Australian Age of Dinosaurs


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:25:01 am
(http://news.nationalgeographic.com/news/2009/07/photogalleries/australia-new-dinosaur-pictures/images/primary/090706-03-new-huge-dinosaur-clancy_big.jpg)

The discovery of Clancy, a huge plant-eating sauropod (seen above in an illustration), confirms that giant dinosaurs existed in what is now Australia, paleontologists said in July 2009.

The 60-foot-long (18-meter-long) dinosaur roamed the region's vast fern-filled plains 98 million years ago in the mid-Cretaceous period, just before the island broke away from Gondwanaland, an ancient supercontinent.

—Images courtesy Travis R. Tischler, Australian Age of Dinosaurs


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:26:30 am
(http://news.nationalgeographic.com/news/2009/07/photogalleries/australia-new-dinosaur-pictures/images/primary/090706-04-new-australian-dinosaurs-bones_big.jpg)

Paleontologist Hocknull examines a huge bone from Matilda, the most complete sauropod skeleton ever found in Australia, in an undated photograph.

Fossils of "strange pythonlike lizards with limbs, crocodiles, turtles, [and] armored dinosaurs" are among the skeletons also uncovered near Matilda's remains in the outback town of Winton, Hocknull said.

Hundreds of bones not yet analyzed will likely reveal more new species, he said. "There's [also] tantalizing evidence in the south of Queensland of really, really big sauropods—perhaps twice the size of Matilda and Clancy," he added.

"We don't have the T. rex yet, but there's every likelihood that we'll find [it]."
—Photograph courtesy Australian Age of Dinosaurs Museum of Natural History


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:27:24 am
(http://news.nationalgeographic.com/news/2009/07/photogalleries/australia-new-dinosaur-pictures/images/primary/090706-05-new-huge-dinos-dig-site_big.jpg)

Paleontologists uncover two rib bones from the newly discovered plant-eating dinosaur Matilda in the Australian outback town of Winton in 2008.

Skeletons of Matilda and a carnivorous dinosaur dubbed Banjo were found buried together in an ancient billabong, or oxbow lake.

The intermingling of their bones suggests the two dinosaurs died at the same time, Hocknull said, and few disturbances to the site over millions of years kept the fossils well preserved.
—Photograph courtesy Australian Age of Dinosaurs Museum of Natural History


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:28:16 am
NEW FOSSIL PHOTOS: "Graceful Weasel," Jewel Bug, More
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-01-messel-pit_big.jpg)

August 21, 2009--This newfound fossil in the Masillamys genus--a group of extinct rodents with chisel-like incisors--is among the exceptionally well-preserved species recently unearthed from the Messel Pit, a paleontological site in Germany.

Although today Messel lies about 12 miles (20 kilometers) southeast of Frankfurt, around 47 million years ago the pit was at the same latitude as modern-day Sicily, where a wetter, warmer climate supported a rich diversity of plants and animals (see a map of Europe).

Annual digs conducted by the Senckenberg Research Institute in Frankfurt have uncovered thousands of fossils of primeval rodents, reptiles, insects, and hoofed mammals that lived in or around Messel during the Eocene epoch, about 55.8 to 33.9 million years ago. At that time the now grassy pit was a volcanic lake surrounded by dense forest.

Some of the artifacts are now on display at the research institute's museum.
— Photograph courtesy Senckenberg Research Institute

http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:29:05 am
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-02-skulls_big.jpg)

Between 2007 and 2008, researchers found more than 6,500 fossils embedded in shale from Germany's Messel Pit, including an ancient ungulate, or hoofed mammal, called Kopidodon macrognathus, whose skull is seen above. Researchers think this animal was a young male, based on its bony head crest and still-developing teeth in its upper jaw.

Despite its long canines, the animal's flat molars, specialized hip joints, and the strong grip of its front limbs suggest the creature was a tree-dwelling fruit-eater, not a predator. The scientists hope that analysis of the animal's preserved stomach contents will reveal more about its lifestyle during the Eocene.
— Photograph courtesy Senckenberg Research Institute


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:29:56 am
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-03-messel-pit_big.jpg)

Seeming to crawl from under a blanket of shale, the fossil of a well-preserved lizard found in Germany has been shown to be an ancient relative of venomous Gila monsters. Modern day Gila monsters are found only in the deserts of the U.S. Southwest and northern Mexico.

The fossil reptile lived about 47 million years ago near a volcanic lake surrounded by a rich diversity of wildlife. Researchers with the Senckenberg Research Institute in Frankfurt, who examined the fossil, say that canals in its teeth suggest the primitive creature was already producing venom.
— Photograph courtesy Senckenberg Research Institute


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:30:40 am
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-04-bumblebee_big.jpg)

An ancient leafcutter bee, Friccomelissa schopowi, was among the more than 1,400 fossil insects found in the Messel Pit site near Frankfurt, Germany, between 2007 and 2008.

Unlike its modern relatives, though, the Messel bee apparently didn't build its nest with disks cut from planet leaves, according to researchers with the Senckenberg Research Institute in Frankfurt who analyzed the fossil.
— Photograph courtesy Senckenberg Research Institute


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:31:13 am
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-05-messel-pit_big.jpg)

Seemingly frozen mid-hop, this fossil of a juvenile Leptictidium was unearthed in Germany's Messel Pit in September 2008. The animal, whose scientific name means "graceful weasel," was a small, carnivorous mammal with a long nose similar to that of an elephant shrew, researchers say.

The scientists aren't sure if the extinct Eocene animal walked on two legs or hopped like a kangaroo, but further examination of its spine might help solve the puzzle.
— Photograph courtesy Senckenberg Research Institute


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:32:02 am
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-06-jeweled-beetle_big.jpg)

About 47 million years after it died, this jewel beetle, found in Germany's Messel Pit, still displays a shimmering metallic coloration.

Both ancient and modern jewel beetles sport their iridescent exteriors thanks to the way different layers in their outer body coverings refract light.
— Photograph courtesy Senckenberg Research Institute


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:32:44 am
(http://news.nationalgeographic.com/news/2009/08/photogalleries/new-fossils-messel-pit-pictures/images/primary/090821-07-wasp_big.jpg)

This drowned weaver ant queen fell to her death around 47 million years ago as she flew over Lake Messel, an ancient volcanic lake that once filled the Messel Pit near modern-day Frankfurt, Germany.

Modern members of the Oecophylla ant genus can be found in the tropics of Africa and Southeast Asia, where they are famed for weaving nests of plant material using silk from their larvae.
— Photograph courtesy Senckenberg Research Institute


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:33:24 am
Biggest Snake Discovered; Was Longer Than a Bus
John Roach
for National Geographic News
February 4, 2009


The world's biggest snake was a massive anaconda-like beast that slithered through steamy tropical rain forests about 60 million years ago, says a new study that describes the ancient giant.

(See pictures of the ancient giant and other huge snakes and watch video.

Fossils found in northeastern Colombia's Cerrejon coal mine indicate the reptile, dubbed Titanoboa cerrejonesis, was at least 42 feet (13 meters) long and weighed 2,500 pounds (1,135 kilograms).

"That's longer than a city bus and … heavier than a car," said lead study author Jason Head, a fossil-snake expert at the University of Toronto Mississauga in Canada and a research associate with the Smithsonian Institution.

Previously the biggest snake known was Gigantophis garstini, which was 36 to 38 feet (11 to 11.6 meters) long. That snake lived in North Africa about 40 million years ago.

Hans-Dieter Sues, associate director for research and collections at the Smithsonian's National Museum of Natural History, was not involved with the study but has seen the snake fossils.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:33:37 am
Sues noted that humans would stand no chance against one of these giants, which killed their prey by slow suffocation.

"Given the sheer size—the sheer cross-section of that snake—it would be probably like one of those devices they use to crush old cars in a junkyard," Sues said.

In addition, the snake's heft indicates that it lived when the tropics were much warmer than they are today, a find that holds potential implications for theories of once and future climate change.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:33:58 am
Biggest Snake Needed the Heat

Scientists know there's a link between a snake's body size, how fast it uses and produces energy, and climate.

(Related: "World's Smallest Snake Discovered, Study Says" [August 3, 20008].)

http://news.nationalgeographic.com/news/2009/02/090204-biggest-snake-fossil.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:34:43 am
"We were able to use the snake, if you will, as a giant fossil thermometer," study author Head said.

His team found that, for Titanoboa to reach its epic proportions, mean year-round temperatures would have been about 90 degrees Fahrenheit (32 degrees Celsius)—significantly hotter than today's tropics.

This supports the idea that tropical temperatures spike as the rest of the world heats up due to global warming, the study authors say.

The competing theory is that, during bouts of warming, the tropics stay about the same average temperatures as they are today while areas north and south of the Equator heat up.

James Zachos, an expert on ancient climates at the University of California, Santa Cruz, who was not involved in the study, agreed.

As the biggest known snake, Titanoboa supports the idea of "much hotter tropics during extreme greenhouse periods," Zachos said.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:35:07 am
Big Reptiles on the Horizon?

Study co-author Jonathan Bloch is a vertebrate paleontologist at the University of Florida's Museum of Natural History in Gainesville.

The same Colombian coal mine that contained the biggest snake also yielded massive turtles and crocodiles, he said.

"You can think about it as an ecosystem dominated by giants, I think, and these are probably giants that got large because of the warmer mean annual temperature," he said.

The findings, detailed in this week's issue of the journal Nature, paint a picture of what the future might hold if supercharged global warming takes place.

According to some models, global temperatures could approach the same levels that gave rise to the biggest snake by the end of this century.

If current greenhouse gas emissions continue apace, there's a chance snakes the size of Titanoboa could return, Bloch said.

"Or maybe snakes would go extinct in the tropics," he said. "In other words, the warming could happen so rapidly that they wouldn't have time to adapt."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:37:24 am
(http://news.nationalgeographic.com/news/images/thumbs/090204-biggest-snake-fossil_170.jpg)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:38:15 am
http://news.nationalgeographic.com/news/bigphotos/37952536.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:38:58 am
Oldest Skeleton of Human Ancestor Found
Jamie Shreeve
Science editor, National Geographic magazine
October 1, 2009


Move over, Lucy. And kiss the missing link goodbye.

Scientists today announced the discovery of the oldest fossil skeleton of a human ancestor. The find reveals that our forebears underwent a previously unknown stage of evolution more than a million years before Lucy, the iconic early human ancestor specimen that walked the Earth 3.2 million years ago.

The centerpiece of a treasure trove of new fossils, the skeleton—assigned to a species called Ardipithecus ramidus—belonged to a small-brained, 110-pound (50-kilogram) female nicknamed "Ardi." (See pictures of Ardipithecus ramidus.)

The fossil puts to rest the notion, popular since Darwin's time, that a chimpanzee-like missing link—resembling something between humans and today's apes—would eventually be found at the root of the human family tree. Indeed, the new evidence suggests that the study of chimpanzee anatomy and behavior—long used to infer the nature of the earliest human ancestors—is largely irrelevant to understanding our beginnings.

Ardi instead shows an unexpected mix of advanced characteristics and of primitive traits seen in much older apes that were unlike chimps or gorillas (interactive: Ardi's key features). As such, the skeleton offers a window on what the last common ancestor of humans and living apes might have been like.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:39:17 am
Announced at joint press conferences in Washington, D.C., and Addis Ababa, Ethiopia, the analysis of the Ardipithecus ramidus bones will be published in a collection of papers tomorrow in a special edition of the journal Science, along with an avalanche of supporting materials published online.

"This find is far more important than Lucy," said Alan Walker, a paleontologist from Pennsylvania State University who was not part of the research. "It shows that the last common ancestor with chimps didn't look like a chimp, or a human, or some funny thing in between." (Related: "Oldest Homo Sapiens Fossils Found, Experts Say" [June 11, 2003].)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:39:37 am
Ardi Surrounded by Family

The Ardipithecus ramidus fossils were discovered in Ethiopia's harsh Afar desert at a site called Aramis in the Middle Awash region, just 46 miles (74 kilometers) from where Lucy's species, Australopithecus afarensis, was found in 1974. Radiometric dating of two layers of volcanic ash that tightly sandwiched the fossil deposits revealed that Ardi lived 4.4 million years ago.

Older hominid fossils have been uncovered, including a skull from Chad at least six million years old and some more fragmentary, slightly younger remains from Kenya and nearby in the Middle Awash.

While important, however, none of those earlier fossils are nearly as revealing as the newly announced remains, which in addition to Ardi's partial skeleton include bones representing at least 36 other individuals.

"All of a sudden you've got fingers and toes and arms and legs and heads and teeth," said Tim White of the University of California, Berkeley, who co-directed the work with Berhane Asfaw, a paleoanthropologist and former director of the National Museum of Ethiopia, and Giday WoldeGabriel, a geologist at Los Alamos National Laboratory in New Mexico.

"That allows you to do something you can't do with isolated specimens," White said. "It allows you to do biology."

(Related: Rediscover the earliest Ardipithecus.)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:40:31 am
Ardi's Weird Way of Moving

The biggest surprise about Ardipithecus's biology is its bizarre means of moving about.

All previously known hominids—members of our ancestral lineage—walked upright on two legs, like us. But Ardi's feet, pelvis, legs, and hands suggest she was a biped on the ground but a quadruped when moving about in the trees.

Her big toe, for instance, splays out from her foot like an ape's, the better to grasp tree limbs. Unlike a chimpanzee foot, however, Ardipithecus's contains a special small bone inside a tendon, passed down from more primitive ancestors, that keeps the divergent toe more rigid. Combined with modifications to the other toes, the bone would have helped Ardi walk bipedally on the ground, though less efficiently than later hominids like Lucy. The bone was lost in the lineages of chimps and gorillas.

According to the researchers, the pelvis shows a similar mosaic of traits. The large flaring bones of the upper pelvis were positioned so that Ardi could walk on two legs without lurching from side to side like a chimp. But the lower pelvis was built like an ape's, to accommodate huge hind limb muscles used in climbing.

Even in the trees, Ardi was nothing like a modern ape, the researchers say.

Modern chimps and gorillas have evolved limb anatomy specialized to climbing vertically up tree trunks, hanging and swinging from branches, and knuckle-walking on the ground.

While these behaviors require very rigid wrist bones, for instance, the wrists and finger joints of Ardipithecus were highly flexible. As a result Ardi would have walked on her palms as she moved about in the trees—more like some primitive fossil apes than like chimps and gorillas.

"What Ardi tells us is there was this vast intermediate stage in our evolution that nobody knew about," said Owen Lovejoy, an anatomist at Kent State University in Ohio, who analyzed Ardi's bones below the neck. "It changes everything."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:41:16 am
Against All Odds, Ardi Emerges

The first, fragmentary specimens of Ardipithecus were found at Aramis in 1992 and published in 1994. The skeleton announced today was discovered that same year and excavated with the bones of the other individuals over the next three field seasons. But it took 15 years before the research team could fully analyze and publish the skeleton, because the fossils were in such bad shape.

After Ardi died, her remains apparently were trampled down into mud by hippos and other passing herbivores. Millions of years later, erosion brought the badly crushed and distorted bones back to the surface.

They were so fragile they would turn to dust at a touch. To save the precious fragments, White and colleagues removed the fossils along with their surrounding rock. Then, in a lab in Addis, the researchers carefully tweaked out the bones from the rocky matrix using a needle under a microscope, proceeding "millimeter by submillimeter," as the team puts it in Science. This process alone took several years.

Pieces of the crushed skull were then CT-scanned and digitally fit back together by Gen Suwa, a paleoanthropologist at the University of Tokyo.

In the end, the research team recovered more than 125 pieces of the skeleton, including much of the feet and virtually all of the hands—an extreme rarity among hominid fossils of any age, let alone one so very ancient.

"Finding this skeleton was more than luck," said White. "It was against all odds."


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:42:09 am
Ardi's World

The team also found some 6,000 animal fossils and other specimens that offer a picture of the world Ardi inhabited: a moist woodland very different from the region's current, parched landscape. In addition to antelope and monkey species associated with forests, the deposits contained forest-dwelling birds and seeds from fig and palm trees.

Wear patterns and isotopes in the hominid teeth suggest a diet that included fruits, nuts, and other forest foods.

If White and his team are right that Ardi walked upright as well as climbed trees, the environmental evidence would seem to strike the death knell for the "savanna hypothesis"—a long-standing notion that our ancestors first stood up in response to their move onto an open grassland environment.


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:42:40 am
Sex for Food

Some researchers, however, are unconvinced that Ardipithecus was quite so versatile.

"This is a fascinating skeleton, but based on what they present, the evidence for bipedality is limited at best," said William Jungers, an anatomist at Stony Brook University in New York State.

"Divergent big toes are associated with grasping, and this has one of the most divergent big toes you can imagine," Jungers said. "Why would an animal fully adapted to support its weight on its forelimbs in the trees elect to walk bipedally on the ground?"

One provocative answer to that question—originally proposed by Lovejoy in the early 1980s and refined now in light of the Ardipithecus discoveries—attributes the origin of bipedality to another trademark of humankind: monogamous sex.

Virtually all apes and monkeys, especially males, have long upper canine teeth—formidable weapons in fights for mating opportunities.

But Ardipithecus appears to have already embarked on a uniquely human evolutionary path, with canines reduced in size and dramatically "feminized" to a stubby, diamond shape, according to the researchers. Males and female specimens are also close to each other in body size.

Lovejoy sees these changes as part of an epochal shift in social behavior: Instead of fighting for access to females, a male Ardipithecus would supply a "targeted female" and her offspring with gathered foods and gain her sexual loyalty in return.

To keep up his end of the deal, a male needed to have his hands free to carry home the food. Bipedalism may have been a poor way for Ardipithecus to get around, but through its contribution to the "sex for food" contract, it would have been an excellent way to bear more offspring. And in evolution, of course, more offspring is the name of the game (more: "Did Early Humans Start Walking for Sex?").

Two hundred thousand years after Ardipithecus, another species called Australopithecus anamensis appeared in the region. By most accounts, that species soon evolved into Australopithecus afarensis, with a slightly larger brain and a full commitment to a bipedal way of life. Then came early Homo, with its even bigger brain and budding tool use.

Did primitive Ardipithecus undergo some accelerated change in the 200,000 years between it and Australopithecus—and emerge as the ancestor of all later hominids? Or was Ardipithecus a relict species, carrying its quaint mosaic of primitive and advanced traits with it into extinction?

Study co-leader White sees nothing about the skeleton "that would exclude it from ancestral status." But he said more fossils would be needed to fully resolve the issue.

Stony Brook's Jungers added, "These finds are incredibly important, and given the state of preservation of the bones, what they did was nothing short of heroic.

But this is just the beginning of the story."

Look for comprehensive coverage of Ardipithecus ramidus in a future issue of National Geographic magazine.

More From National Geographic Magazine
• Fossil Ape: Human Ancestor?
• Childhood Origins
• Human Evolutionary Highway

More Human Evolution News Coverage
• Humans, Chimps Not as Closely Related as Thought? (September 24, 2002)
• Chimps Belong on Human Branch of Family Tree, Study Says (May 23, 2003)
• Oldest Human Fossils Identified (February 16, 2005)
• Chimps, Humans 96 Percent the Same, Gene Study Finds (August 31, 2005)
• Human Genome Shows Proof of Recent Evolution, Survey Finds (March 8, 2006)
• Human, Chimp Ancestors May Have Mated, DNA Suggests (May 17, 2006)
• Human Evolution Speeding Up, Study Says (December 11, 2007)
• "MISSING LINK" FOUND: New Fossil Links Humans, Lemurs? (May 19, 2009)
• Orangutans May Be Closest Human Relatives, Not Chimps (June 23, 2009)


http://news.nationalgeographic.com/news/2009/10/091001-oldest-human-skeleton-ardi-missing-link-chimps-ardipithecus-ramidus.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:43:03 am
(http://news.nationalgeographic.com/news/images/thumbs/091001-oldest-human-skeleton-ardi-missing-link-chimps-ardipithecus-ramidus_170.jpg)


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:44:27 am
http://news.nationalgeographic.com/news/bigphotos/85209423.html


Title: Re: Top Ten Dinosaur and Fossil Finds: Most Viewed of 2009
Post by: Tyrannosaurus Rex on December 28, 2009, 06:45:25 am
"MISSING LINK" FOUND: New Fossil Links Humans, Lemurs?

(http://news.nationalgeographic.com/news/2009/05/images/090519-missing-link-found_big.jpg)

May 19, 2009—Meet "Ida," the small "missing link" found in Germany that's created a big media splash and will likely continue to make waves among those who study human origins.

In a new book, documentary, and promotional Web site, paleontologist Jorn Hurum, who led the team that analyzed the 47-million-year-old fossil seen above, suggests Ida is a critical missing-link species in primate evolution (interactive guide to human evolution from National Geographic magazine).

(Among the team members was University of Michigan paleontologist Philip Gingerich, a member of the Committee for Research and Exploration of the National Geographic Society, which owns National Geographic News.)

The fossil, he says, bridges the evolutionary split between higher primates such as monkeys, apes, and humans and their more distant relatives such as lemurs.

"This is the first link to all humans," Hurum, of the Natural History Museum in Oslo, Norway, said in a statement. Ida represents "the closest thing we can get to a direct ancestor."

Ida, properly known as Darwinius masillae, has a unique anatomy. The lemur-like skeleton features primate-like characteristics, including grasping hands, opposable thumbs, clawless digits with nails, and relatively short limbs.

"This specimen looks like a really early fossil monkey that belongs to the group that includes us," said Brian Richmond, a biological anthropologist at George Washington University in Washington, D.C., who was not involved in the study, published this week in the journal PLoS ONE.

But there's a big gap in the fossil record from this time period, Richmond noted. Researchers are unsure when and where the primate group that includes monkeys, apes, and humans split from the other group of primates that includes lemurs.

"[Ida] is one of the important branching points on the evolutionary tree," Richmond said, "but it's not the only branching point."

At least one aspect of Ida is unquestionably unique: her incredible preservation, unheard of in specimens from the Eocene era, when early primates underwent a period of rapid evolution. (Explore a prehistoric time line.)

"From this time period there are very few fossils, and they tend to be an isolated tooth here or maybe a tailbone there," Richmond explained. "So you can't say a whole lot of what that [type of fossil] represents in terms of evolutionary history or biology."

In Ida's case, scientists were able to examine fossil evidence of fur and soft tissue and even picked through the remains of her last meal: fruits, seeds, and leaves.

What's more, the newly described "missing link" was found in Germany's Messel Pit. Ida's European origins are intriguing, Richmond said, because they could suggest—contrary to common assumptions—that the continent was an important area for primate evolution.

MORE: National Geographic magazine's Chris Sloan on the controversy over the "missing link" and its media blitz >>

http://news.nationalgeographic.com/news/2009/05/090519-missing-link-found.html