WASHINGTON — A dinosaur with a strange jaw designed to hoover-up food grazed in what is now the Sahara Desert 110 million years ago.

Remains of the creature that “flabbergasted” paleontologist Paul Sereno went on display Thursday at the headquarters of the National Geographic Society, where they will remain until March.

Sereno and colleagues recovered, assembled and named the creature — Nigersaurus taqueti — that he said seems to break all the rules, yet still existed.

“The biggest eureka moment was when I was sitting at the desk with this jaw,” he said. “I was sitting down just looking at it and saw a groove and … realized that all the teeth were up front.”

It’s not normally a good idea to have all the teeth in the front of the jaw — hundreds in this case.

Sure, “it’s great for nipping,” Sereno said, “but that’s not where you want do your food processing.”

“That was an amazing moment, we knew we had something no one had ever seen before,” Sereno recalled.

Sereno, a National Geographic explorer-in-residence and paleontologist at the University of Chicago, said the first evidence of Nigersaurus was found in the 1990s and now researchers have been able to reconstruct its skull and skeleton.

While Nigersaurus’ mouth is shaped like the wide intake slot of a vacuum, it has something lacking in most cleaners — hundreds of tiny, sharp teeth to grind up its food.

The 30-foot-long Nigersaurus had a feather-light skull held close to the ground to graze like an ancient cow. Sereno described it as a younger cousin of the North American dinosaur Diplodicus.

Its broad muzzle contained more than 50 columns of teeth lined up tightly along the front edge of its jaw. Behind each tooth more were lined up as replacements when one broke off.

Using CT scans, the researchers were able study the inside of the animal’s skull where the orientation of canals in the organ that helps keep balance disclosed the habitual low pose of the head, they reported.

Nigersaurus also had a backbone consisting of more air than bone.

“The vertebrae are so paper-thin that it is difficult to imagine them coping with the stresses of everyday use — but we know they did it, and they did it well,” said Jeffrey Wilson, assistant professor at the University of Michigan and an expedition team member.

The dinosaur’s anatomy and lifestyle were to be detailed in the December issue of National Geographic magazine.

The first bones of Nigersaurus were picked up in Niger in the 1950s by French paleontologists led by Philippe Taquet, but the species was not named at that time. Sereno and his team honored this early work by naming Nigersaurus taqueti after the nation where it was found and the French scientist.