T. Rex Redux

Field Scientists Scan Bones To Learn Even More About Sue The Dinosaur

August 08, 1999|By Connie Lauerman, Tribune Staff Writer.

Technicians have been cleaning and preparing the fossilized bones of Sue, the gigantic, 67-million-year-old Tyrannosaurus rex dinosaur, in full view of the public since last year at the Field Museum and in an exhibit at Disney World in Orlando.

But behind the scenes, scientists are engaged in an even more detailed and methodical pursuit. They're examining those same bones in an effort to learn more about the anatomy, behavior and lifestyle of the fierce carnivore.

Nineteen scientists have been working on putting Sue back together for her debut next May at the museum. Once completed, Sue's entire skeleton will be carefully arranged on a metal armature, posed bending over from the hips, as if to pounce. It will measure 13 feet high at the hips and 41 feet long.

Last month, several of Sue's bones, including a rib, a rib fragment and a forelimb, were taken to Good Samaritan Hospital in Downers Grove for X-rays and CT scans. The resulting images are now being examined by a paleopathologist.

"Some of the bones have abnormalities, (from) injury or disease," said Barbara Ceiga, the museum's senior exhibit developer. "On the outside it looks like a bump, but on the inside it could be any number of things. The paleopathologist would compare those to other known conditions in bones of mammals and humans and try to narrow down what the diagnosis might be.

"Now 60 million years ago you don't know if there were certain things like tuberculosis, so you can't really narrow it down exactly. But the difference between a broken bone and a diseased bone should be able to be diagnosed.

"We do know that bones broke back then just like they break today, and there are other conditions that have been around for a long time. For example, anything that would involve a basic element like uric acid. Gout is caused by the build-up of uric acid in the joint. There might be other infections they'll be looking for as well."

Sue is the biggest and most complete T. rex skeleton ever found. Although its sex is unknown, it was named Sue after Susan Hendrickson, the fossil hunter who discovered it in South Dakota in 1990. The Field Museum bought it in 1997 for $8.4 million in conjunction with McDonald's and Walt Disney World Resorts, both of which will use the dinosaur's image and reproductions of its skeleton in their own promotions.

Last year, Sue's 2,000-pound skull was transported to California's Ventura County for an industrial CT scan at the Boeing Company's Rocketdyne Propulsion & Power Santa Susana Field Laboratory.

Fossil preparators have now gone back to work on the skull, which may yield clues about how the animal functioned and how it's related to other animals.

"How the bones of the skull are arranged is indicative of where we are in this massive evolutionary tree," Ceiga said.