Their Land Before Ours

The Discovery Channel documentary “When Dinosaurs Roamed America” introduces newly discovered dinosaur species--a well as flora and fauna-- from the Cretaceous Gap, a period some 75 million to 105 million years ago, from which no dinosaur species previously had been found.

As with Discovery’s popular “Walking With Dinosaurs” broadcast last year, this new two-hour documentary, showing Sunday, uses state-of-the-art computer imagery to bring to life the vast array of dinosaurs that roamed across America for 150 million years.

Among the new dinos featured are a two-legged, meat-eating member of the Coelurosaur species, yet unnamed, and Nothronychus, a bizarre, long-necked plant-eater that lumbered like a bear and was related to such theropod dinosaurs as the Tyrannosaurus rex.

The special also animates Zuniceratops, which made headlines in 1999 when it was discovered by the 9-year-old son of Doug Wolfe, the principal investigator and director of the Zuni Basin Paleontological Project. Boasting unique horns and frills, the Zuniceratops were small--about 10 to 12 feet in length--and were the first animal to have horns over its eyes. It also lacked any nose horn.

The computer animators relied heavily on scientists to show them how these dinosaurs moved and behaved.

“One of the things that has happened recently is that paleontologists have been able to look at the bones and reconstruct in a computer environment how they would be put together,” says producer John Copeland. “They were able to give us a crash course in how these guys move and possibly held themselves at rest.”

Jim Kirkland, state paleontologist of Utah with Utah Geological Survey, actually walked like a dinosaur for the animators. “He acted like a big, giant plant-eater,” says Copeland. “He spent two four-hour sessions [with the animators].”

Thomas Holtz, vertebrate paleontologist and lecturer at the University of Maryland, was impressed with the animators’ willingness to work with the scientists.

“When I was up in Montreal at the animation studio consulting at one point, I found a few things I would disagree with,” he says.

“They went back and modified it. But, of course, paleontologists deal with lots of question marks. If we don’t have the top of the skull of a dinosaur--sometime we may find it--we can use dotted lines. But when you are doing these animated reconstructions, you can’t use dotted lines, so we help to fill in the gaps to complete the animals and the same sort of thing with their behaviors.”

“When Dinosaurs Roamed America,” which airs three days before the opening of “Jurassic Park III,” also features feathered dinosaurs that are based on recently released data from new discoveries in China and North America.

“It’s really cool,” says Holtz. “Feathers are very, very rarely preserved ... they just decay away. But these particular dinosaurs [in China] sank into a lake bed that had extremely fine-grain mud that preserved the impression of feathers, so that is why we were able to see what was on the outside.”

Holtz says that one of the messages of the documentary is that scientists still only know a tiny fraction of what happened during prehistoric times. “We can still find new communities of dinosaurs and other extinct species,” he says.

Scientists are uncovering more and more dinosaur sites because paleontologists are “getting to places where people hadn’t been before,” says Holtz. “

“There had been geologists who worked in the Zuni Basin before, but nothing in the way of an organized dig in those rocks. Once you got Jim Kirkland and Doug Wolfe organizing their teams to get people on the ground, [things changed].... The same thing going on in these expeditions is going on in Mongolia and North Africa.”

Besides, he says, there aren’t many geologists trained to study dinosaurs. “I guess we are probably around 200 professional paleontologists,” Holtz says. “That is the most we’ve had working in the community at once.”

Holtz points out it’s the pop culture side of dinosaurs that draws people into the field. “Most paleontologists had some sort of childhood fascination because of a movie or TV show,” says Holtz.

“Apparently, I really wanted to be a dinosaur,” Holtz says. “My parents said it wasn’t going to happen, so I decided I would study them.”

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* “When Dinosaurs Roamed America” airs Sunday at 8 p.m. on the Discovery Channel. The network has rated it TV-G (suitable for all ages).