LAS VEGAS – A place that rarely preserves its past is trying to preserve its pasties.

Make that pasties and crystal bras, feathered head pieces, fans and thongs – anything that documents the existence of an increasingly rare bird: the showgirl.

“We were the original Las Vegas,” says Lou Anne Harrison Chessik, the former showgirl behind a new exhibit that memorializes the garb and glamour of her withering art. “It’s important to me that we understand this history.”

There are just two large-scale showgirl revues left on the Las Vegas Strip, so very different from the 1960s when every respectable casino housed its own flock of beauties in boas. Their bloodlines may trace back to the French cancan girls of the 19th century, but it took the one-upmanship of Las Vegas to make them icons. Now, they’re fading from the stage, and Chessik and others are part of a still young movement to make sure they’re not forgotten.

To that aim, Chessik has created the annual Showgirl Art Competition, an exhibit in its second year on display until August at the Nevada State Museum in Las Vegas. It is likely the only state museum to display a G-string a spin and a twirl away from 225 million-year-old Ichthyosaur fossils.

The costumes on view include glittering skivvies designed by Cher’s costume designer Bob Mackie, a cherry-colored feathered flurry called “Red Heat Wave” and other high art of the genre. But the exhibit’s focus is artwork depicting the bare-chested performers themselves. It includes the work of Terry Ritter, a dancer-turned-artist who set up her easel backstage at the shows to create dreamy portraits.

More improbably, it includes the artwork of high school students, who were likely stunned by their luck when a still lean, leggy Chessik, 51, and a group of former dancers arrived in their classroom to regale them with the history of the showgirl.

The homework: paint portraits of dancers. Think Edgar Degas, think Henri Toulouse-Lautrec.

Chessik knows this is a new world for most teenagers – even teenagers in Las Vegas. The French-Canadian acrobats of Cirque du Soleil now dominate the entertainment scene of the Strip. The word “showgirl” has been adopted by far less glamorous establishments.

“A lot of strippers and different groups use the name, ‘showgirl’ now,” she says, somewhat embarrassed.

“The movie ‘Showgirls’ didn’t help,” adds Tom Dyer, the museum’s exhibit manager, referring to the 1995 Elizabeth Berkley bomb.

This wasn’t always so. Some of the first showgirls in Las Vegas were classically trained European ballerinas who arrived to perform in “Lido de Paris,” a review imported in 1958 by producer Donn Arden.

“Lido” was among the first topless shows on the Strip and initially caused a stir, which Arden quieted by inviting the chief of police and the city council to the opening. Arden was prepared to cover up the girls if the city fathers disapproved, says Peter Michel, director of special collections at the University of Nevada, Las Vegas, which houses Arden’s papers.

“But they didn’t. They thought it was fine. As a matter of fact, they thought it was wonderful,” he says. “And because it was so popular and attracted so many tourists, it guaranteed that it was going to be to be copied.”

As Arden’s shows went through various iterations, he continued to demand that his dancers be trained dancers. They were known as the tallest showgirls on the Strip.

Few understand just how over the top these shows were in their heyday as much as Karen Burns. Burns provided some of the costumes on display at the museum. The rest are stored in a warehouse she had to build to house the more than 1,000 pieces she acquired.

A former dancer in the show, Burns says the massive production employed 150 dancers, many of whom had more than 10 wardrobe changes. Its stage was the size of a football field. Its most famous number involved 10 dancers dressed like stewardesses in bejeweled bikinis riding in on the wings of a DC-10 mock-up. Chessik, who performed in the show, can still strike the pose on cue.

But the cost of such spectacles grew untenable as casinos suffered through slow economic times in the 1980s. Headliners became a more popular and more affordable way to draw crowds. A push to make Las Vegas “family friendly” didn’t help.

And so the parades of topless ladies eventually were replaced by even more lavish, outlandish acrobats and contortionists. In an effort to compete, “Jubilee!” has recently offered a new “not topless” show open to ages 13 and up.

“The show is not just about girls, it’s about song and dance. It’s a tribute to Hollywood. It’s something kids can’t see anywhere else,” says the show’s 85-year-old company manager Fluff LeCoque.

That may change if Chessik and Burns are successful in their push to secure the showgirl’s place in history. Chessik plans to continue her work in schools. Burns dreams of a traveling exhibit for her costume collection.

On a recent day, at least one student was drawn away from the dinosaur bones by a nearly nude mannequin encased in rhinestone-lined hoops and sprouting a feather headdress.

As she admired Mackie’s “The Cage,” 11-year-old Danje Elliott pointed to Chessik as she stood nearby.

“Who is she?” she asked.

“She was a showgirl,” Elliott was told.

“Wow.”