Slideshow ( 3 images )

(Reuters) - Sue, the largest, most complete and best-preserved Tyrannosaurus rex ever unearthed, gets to show off its new lair this week at the Field Museum in Chicago.

The museum on Friday will unveil the 40-1/2-foot-long (12.3-meter) Sue, one of the world’s best-known dinosaur fossils, in the giant meat-eater’s new permanent exhibition space after 10 months of work moving and remounting the huge bones. Sue’s bones were mounted in a way that reflects new understanding about the species acquired over the past two decades.

One major change was the addition of gastralia, bones resembling an additional set of ribs spanning the belly that may have provided structural support to help the dinosaur breathe.

“The gastralia form a basket of bones in the abdominal wall and really help us visualize the size and girth of Sue. We also adjusted the shoulder blades to fit with what we now consider to be the correct wishbone, and this had the effect of bringing the arms lower and closer to the midline. Sue can now clap,” said paleontologist Pete Makovicky, the museum’s associate curator of dinosaurs.

Sue is named for the woman who discovered the fossils in South Dakota in 1990. It is not clear whether the actual dinosaur was female or male. The museum bought the fossils at auction for $8.4 million and put Sue on display in 2000.

“Adjustments were also made to the ribcage and the right leg is less flexed. Finally, we gave the mount a slightly wider gape for dramatic effect,” Makovicky added. “The new exhibit is a smaller, more intimate space, so the sheer size of the skeleton comes across in a much more visceral way.”

T. rex, one of the largest land predators ever, roamed western North America during the twilight of the age of dinosaurs during the Cretaceous Period, alongside horned dinosaurs, armored dinosaurs, duckbilled dinosaurs, flying reptiles called pterosaurs, birds with and without teeth and other creatures.

An asteroid impact off the coast of Mexico 66 million years ago doomed the dinosaurs and many other land and sea creatures, though mammals survived the calamity and later became dominant.