Image: Vertebrae and child
Some of the fossil vertebrae from the Argentinosaurus, found in Argentina's Patagonia region, are bigger than a child.
By Alan Boyle Science editor
msnbc.com

It was the shoulder blade that really got to Bill Bevil — a synthesized bone that’s bigger than a Volkswagen.

“When you actually see it, it’s quite stunning,” said Bevil, exhibit manager for Atlanta’s Fernbank Museum of Natural History.

And that’s the whole point behind the museum’s effort to transform one of the world’s biggest dinosaur finds from a smattering of bones into a 100-foot-long skeletal spectacle: Now the entire world is able to see it.

Bevil and other staff members from the Fernbank Museum traveled to Argentina to see the transformation for themselves. Working from the fossilized remains and assisted by 3-D visualization software, paleontologists and sculptors re-created the full skeleton of Argentinosaurus, a 100-ton, 100-foot-long plant-eater that is considered the most massive dinosaur species yet documented.

The 85-million-year-old creature, part of the sauropod branch of the dinosaur family tree, had a small head atop a long neck that could rise to a height of three or four stories, and backbones that measured up to 5 feet in width.

The first fossilized traces of the creature were found in 1987 in Argentina’s Patagonia region, which has emerged as the world’s hottest spot for finding the biggest dinosaurs. The current record-holder among meat-eaters, 45-foot-long Giganotosaurus, was found in the same area, as were the remains of what promises to be an even bigger carnivore.

All these creatures lived during the Cretaceous period, when the present-day Patagonian desert was a lush paradise for dinosaurs with big appetites.

No one can say why dinosaurs grew so large in South America, said Rodolfo Coria, a paleontologist who played a part in most of the biggest finds. However, the fact that the continent was cut off from other land masses during the Cretaceous period helps explain why South America’s species were so distinctive, he told MSNBC.com in a telephone interview.

“Being isolated for so long, the fauna evolved in their own way, and the evolution produced some forms which are not recorded in other parts of the world because of this biogeographical isolation,” he said from Plaza Huincul, where he is director of the Carmen Funes Municipal Museum.

Although just 5 percent of the Argentinosaurus’ skeleton has been excavated so far, Coria said researchers are already learning a lot about the limits of dinosaurian physiology. He said the behemoth’s bones exhibited “very interesting adaptations,” including backbones that interlocked in a special way.

“The whole back of the animal worked like a bridge of bone, strong enough for supporting the weight of the animal, but light enough to produce such a big animal,” he said.

The bones were also hollow, which is unusual for sauropods but may have served as another evolutionary strategy for maximizing size and strength in relation to weight.

An unprecendented view
While paleontologists continue to excavate and study the bones themselves, copies have been made of some of them — but until now, no one has had the wherewithal to mount an entire Argentinosaurus skeleton. Fernbank’s $1 million-plus effort is the first.

“This project is a very expensive project, and Fernbank Museum has been the first museum with enough funding for this project. ... The budget for building this monster was completely out of our possibilities,” Coria said.

There were other hurdles besides sheer cost: For one thing, paleontologists have so far recovered only 5 percent of the skeleton, primarily vertebrae and the hip bone. The rest of the frame had to be reconstructed virtually, based on fossils from similar but smaller dinosaurs.

Cross-sections of each bone were sculpted out of slabs of plastic foam. The layers were sandwiched together, smoothed down, coated with a thin veneer of clay, then texturized to look like the real thing.

Each ersatz bone was covered with silicone plastic to produce a mold, then that mold is used to cast the finished set of hollow plastic bones. “After the mold is made, you basically can toss out the original prototype,” Bevil said.

Image: Museum
An artist's conception shows how Giganotosaurus and Argentinosaurus are displayed at Atlanta's Fernbank Museum of Natural History.
After months of work, the lightweight plastic bones were assembled in Fernbank’s 72-foot-high great hall in early 2001, joining a menacing Giganotosaurus display that was erected a year earlier. In Fernbank’s staging of the dino-drama, Argentinosaurus plays the role of prey, with a flock of pterosaurs flying overhead and a path of dinosaur tracks, cast from Patagonian trackways, stretching away from the dinosaurs’ feet.

Although you’ll have to visit the museum to get the full effect, you can also get a sense of the project over the Internet, courtesy of Fernbank’s “Dino Cam.” (Click on “Live Cameras” from this page.)

Now that the molds have been made, Coria hopes other museums eventually will be able to cast additional copies of the Argentinosaurus skeleton — serving as a means to bring extra income to his own museum for further research.

Scientific speculation
Bevil acknowledged that there was a lot of speculation involved in putting together the display. For example, the Giganotosaurus fossil unearthed in Argentina is thought to be 10 million years older than the Argentinosaurus specimen.

“However, scientists can surmise that because the dinosaurs lived in the same region, and because that’s a fairly close time period, there probably were predators that were either very similar to or maybe even the same as Giganotosaurus at the same time as Argentinosaurus,” Bevil said.

Bevil is also including a strain of pterosaur found only in coastal sediments in Brazil, known as Anhanguera santanae.

“We debated whether or not to show Anhanguera. ... We actually were interested in speculating on the idea that maybe dinosaurs migrated, that maybe sometimes pterosaurs may have traveled inland,” he said. “So in a way, as long as you point out that you did it intentionally, and you can talk about why you’re trying to show this and make people think, then it works.”

The display may be tweaked in the future to reflect the latest findings about how dinosaurs lived, said Anita Kern, the museum’s director of external programming.

“As the science changes, we’ll of course change our content,” she said. “We’re really concerned to present the thought process as well as the facts ... the idea that not everything is totally known.”

The hunt continues
Meanwhile, Coria and others are continuing the big-dino hunt in Argentina. In 1999, there were reports about a “Rio Negro Giant” that surpassed Argentinosaurus in size, but Coria contends that the whole affair “was an overestimated finding.” The size of the bones was in line with those attributed to other sauropods, and the bones were so damaged that “they’re completely useless,” he said.

No research has yet been published on the discovery, and the fossilized creature has not been granted a formal scientific name.

“This thing, in terms of paleontological research, never happened,” he said.

At the same time, Coria says size isn’t everything. His main focus is learning how different species evolved and lived together during the age of the dinosaurs.

“Most of the ecosystems of Patagonia are incompletely known, so our goal is to try to bring more pieces of this puzzle, in order to have a good view of the whole picture,” he said.

And if someone else finds another dinosaur species that turns out to be truly larger than Argentinosaurus, Coria said that would be just fine with him.

“It would be a great advance in our knowledge to know that Argentinosaurus is not showing the size limit for dinosaurs,” he said. “But so far it hasn’t happened.”

This is an updated version of a report that was originally published in September 2000.

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