In a palatial new boneyard, the Smithsonian's Hall of Dinosaurs, the dynasty that dominated Earth for 140 million years bares all.

Above a sepulchral centerpiece of prehistoric leftovers hangs a replica of Quetzalcoatlus northropi, the largest flying animal ever known to inhabit earth. Covered in fake fur, the reptile, named for a Toltec god and a test plane, glides above the stories-high hall, insatiably searching for food. With a 40-foot-wing span and a beak like the hood of a Buick, the thing is nearly as imposing as the Diplodocus longus, a 90-foot plant eater grazing below.

Diplodocus, discovered in Utah in 1923, is a longtime big draw at the Museum of Natural History, says Ian Macintyre, chairman of the general committee that revamped the hall. Before remodeling began, visitors would give the monstrous herbivore the once-over and head for the Hope Diamond. But Macintyre thinks the new look of "evolution as seen in the fossil record" will compel them to ponder other exhibits like Antrodemus, a fierce 10f-by-30f predator debuting this Friday or Dinichthyes, a 300- million-year old answer to "Jaws," whose horrible skull has menaced the museum through these many years.

Just past this nasty bit of seafood is an old favorite fake, a papier-maach,e replica of Stegosaurus, said to have been made of old money shredded by the Treasury Department. But during the renovation, "Old Money Bags" was examined by the G-men and found counterfeit. Stegosaurus has been surrounded with plastic palms, and underfoot roam a pack of Upper Jurassic rodents.

The rodents look a lot like Washington's rats, except their noses are more pointed. Also familiar is a photograph of 20th Street NW with its gingko trees, once believed extinct until rediscovered in China. The fan- shaped leaves are part of a section called "Living Fossils," which has two live crocodiles, a horseshoe crab aquarium, a redwood tree and corresponding fossils.

To demonstrate how fossils affect everyday living, the Museum has included a display of 12-foot-high monoliths formed of fossils -- a coal seam from West Virginia, a limestone quarry face from North Carolina and a phosphorite slab from a Florida mine.

Like Stonehenge on a balcony, the monoliths are reached by a ramp that winds past the "fish in a fish," a huge ray-fin whose last meal 350 million years ago still sticks to his or her ribs.

Below all that, there is fowl play: a touchable cast of Archaeopteryx, the first bird. The first Archaeopteryx fossils were thought to be baby dinosaurs until one was dug up with feathers intact in 1861. A cast of a baby "duckbill" dinosaur, one of 15 found in a nest in Montana in 1978, is available for comparison. There is also a clutch of fossilized dinosaur eggs.

Dinosaurs' film counterparts are seen in "A Star Is Hatched," which screens in the hall's pocket theater. Clips from "One Million Years, B.C.," "The Land Time Forgot," and other dino classics show how Hollywood brought beast and man together, despite the 60-million-year gap between the former's extinction and the latter's evolution.

To bury the myth, a 27-foot tower of time ticks away 700 million years in relative, atomic and geologic increments. Artist John Gurche's luminous, lovely murals show the metamorphosis of life forms -- jellyfish to dinosaur to man -- through the eons. Man, only 40,000 years old, is given an extra 50 million years; if he were drawn to scale, he'd be too small to be seen.

HALL OF DINOSAURS opens at 10 this Friday at the Museum of Natural History. Young Associates are invited to celebrate with dinosaur songs, ginger ale and Tyrannosaurus cookies, from 6 to 7:30 p.m. or 8 to 9:30 p.m. Sunday, from 12:30 to 5, there's a draw-in for artists, 12 years and up. Bring supplies. Professional illustrators will lend a helping pen. The Dinosaur Film Festival, featuring 17 works, opens December 26 and runs through January 2 in the Museum's Baird Auditorium, at noon daily.