Alyssa Cwanger, Post-Gazette Dinosaur Mount Maker Paul Zawisha, begins the process of removing, or disarticulating the skull from the Allosaurus fragilis and packing it in a crate with the assistance of Larry Lee yesterday afternoon at the Carnegie Museum of Natural History. Zawisha, from Milford, Pa., and Lee, from Madison, N.J., work for Phil Fraley Productions, Inc., of Hoboken, New Jersey. Click photo for larger image. Related stories Expansion of Carnegie's Dinosaur Hall under way (March 11, 2005) Museum starts a two-year modernization project (March 9, 2005) Coverage from the Carnegie Museum Web site.

Two men stood perched atop folding ladders. One cradled the skull of the meat-eating allosaurus, his hands tucked behind its 3-inch curved serrated teeth. The other probed under the jaw with a screwdriver.

Onlookers stood in silence until four screws were removed, then burst into applause as the head was walked down the ladder and promptly placed in a foam-filled crate.

The delicate task of dismantling dinosaurs, some of them assembled almost a century ago, began yesterday when crews took off the 70-year-old papier mache skull filled with faux rock at the Carnegie Museum of Natural History, which has one of the oldest and largest dinosaur collections in the country.

Starting today and for the next three years, visitors will be able to watch as five fossilized skeletons are taken apart and put back together as part of a $35 million renovation of the Pittsburgh museum's almost century-old Dinosaur Hall.

The Dinosaur Hall now is home to 15 skeletons of dinosaurs, including some by which all other skeletons are judged -- the diplodocus (found in 1899 and now the museum's mascot, nicknamed "Dippy"), the Apatosaurus louisae (formerly known as the Brontosaurus and named for Carnegie's wife when it was found in 1909) and the tyrannosaurus rex (the first one found in 1902 and bought from the American Museum of Natural History in 1941).

Those three dinosaurs as well as the allosaurus and the protoceratops will be reassembled in more dramatic and scientifically accurate poses.

Over the next nine months, Phil Fraley and his team from Hoboken, N.J., will take apart the dinosaurs piece by piece and box them up in specially made crates filled with foam. They'll be trucked to New Jersey where they will be repaired and restored so they will last another 100 years.

Fraley has been taking apart and putting dinosaurs back together for museums for the past 15 years. He gave the tyrannosaurus rex at the American Museum of Natural History in New York a makeover, switching its stance from a Godzilla-like pose to a horizontal, tails-up, predatory posture. He also worked over "Sue," the largest and most complete T. rex skeleton found, at Chicago's Field Museum of Natural History.

He has wanted to get his hands on the Carnegie's collection for at least seven years. Fraley worked as a consultant with the museum in 2001, looking over the fossilized skeletons to see how well they fared.

"Looking at these, what you are dealing with are irreplaceable objects. Paleontologists might continue to find specimens around the world but the completeness and uniqueness of these will never be found again. This is a treasure," Fraley said.

Fraley's job is a mix of construction and conservation. He's been looking at the fossils and records of how they were put together. The oldest is the sauropod Diplodocus carnegii (named for steel magnate Andrew Carnegie), the museum's first skeleton and the first resident of the Dinosaur Hall, which opened in 1907.

"We all realize that if anything should happen to the specimen -- well, we don't want to go there," Fraley said.

The restoration will be painstakingly documented so one day it can be redone.

"You never do anything that can't be undone. You never know when a scientist 100 years in the future will find that anatomically, something is not right," Fraley said.