LAS VEGAS — Toyota unveiled the next-generation 2016 Prius hybrid in a glitzy presentation here, hyping the hybrid car’s sleeker new lines and saying it will add another 10% to its already impressive fuel economy rating.

The reveal took place under an open sky at the Linq Hotel with a band and lots of flashing lights. Though the reveal occurred past 9 p.m., many of the 350 in attendance glistened with sweat in 90-degree-plus temperatures. A local radio deejay emceed the event.

The fuel-economy boost should allow Toyota to maintain the 2016 Prius as the country’s gas-mileage champ among cars that don’t come with a plug, with an average of about 55 miles per gallon. The current 2015 Prius is rated at 50 mpg. It will be helped by lighter hybrid components and a battery with higher energy density.

In a surprise move, Toyota says it will make an “Eco” version of the Prius, which is unusual since the whole point of the current car is to be economically friendly and easy on gas.

But the big talking point of the new Prius is its new looks, with a high-tech looking front end, dramatic creases running along the sides and new, dramatically vertical taillights in the rear. The new generation will have more passenger room since it’s 2.4 inches longer, 0.6 inches wider and 0.8 inches lower than the outgoing Prius.

“Prius set the global benchmark for hybrids, but now is breaking its own boundaries with more engaging style and fun-to-drive dynamics,” said Bill Fay, general manager of the Toyota Division.

The opulent launch shows Toyota’s faith in the resurgence of a model whose sales seem tied to the price of gas. Prius had been around for about eight years before it became a household word when gas prices peaked in 2008. Since then, it has seen sales swoons when gas prices went high. But they have fallen lately — down 16.8% through the first eight months of the year compared to the same period last year, Autodata says — now that fuel costs are lower.

Auto buying site says Prius not only is taking a hit because of less care about gas thrift but also because the whole compact-car category has dived.

It says the model’s retail share of the category peaked at 10.3% in 2012 but now is down to 6.6%, its lowest since 2006. Plus, an average Prius is spending 70 days on sales lots. Although that’s not far off the industry norm, it’s unusual for a model that dealers once couldn’t keep on the lot.

It’s also strange to see incentives for the model, with discounts averaging $2,600, TrueCar says.

“Prius is not launching at an ideal time,” TrueCar vice president Eric Lyman says. But “gas prices are cyclical in nature, so should fuel prices rise again, Prius can quickly regain favor.”

Follow Laura Petrecca on Twitter at @LauraPetrecca and Chris Woodyard, who reported from Los Angeles, at @chriswoodyard