Standing tall. The newly mounted Triceratops has a more upright posture.

Triceratops Is No Slouch

One of the first dinosaurs ever to go on display has received an unprecedented high-tech upgrade. Scientists at the Smithsonian's National Museum of Natural History today unveiled their new $1 million mounting of Triceratops horridus, made possible through scanning, computer modeling, and a highly accurate dog-sized replica. The new posture takes some of the sprawl out of the dinosaur's front limbs, solving the problem of how the creature stood.

The Triceratops made its public debut in 1905. At that time, dinosaurs were thought to be reptilian and cold-blooded, so the skeleton was assembled with its front limbs splayed out, much like a lizard. In the 1980s, researchers started thinking of such dinos as warm-blooded, leading some to envision Triceratops standing erect with its legs under its body, like an elephant.

In 1999, when Smithsonian curators removed the skeleton from display for repair, paleontologist and computer specialist Ralph Chapman began to study the bones. He and his colleagues scanned each bone to make a computer model that would help reveal how the animal walked. Because the original skeleton consisted of bones from a dozen or so individuals, the scans were also used to create plaster casts that fit together better. The skull, for example, was enlarged by 15%. New hind feet were added to replace the originals, which had belonged to a duck-billed dinosaur.

Before the skeleton was assembled, however, Chapman had a 1:6 scale model created from the computer files. "The miniature bones allowed us to play with the articulation," Chapman says. The scientists discovered that the shoulder joints would have worked smoothly only if the front limbs had been neither erect nor sprawled low to the ground, but in between.

The new assembly is "a robust solution to a long-standing problem," says paleontologist Peter Dodson of the University of Pennsylvania in Philadelphia. Dodson has long argued that the limbs must have fit this way, and he's thrilled with the posture. "I'm doing backflips," he says.

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