The life-size skeletal model of Nigersaurus taqueti at National Geographic Society.

WASHINGTON — The high school students, scientists-in-training from Chicago, had been to archaeological dig sites in the United States and set up a Web site about their work. Then, last month, 10 of them came to the National Geographic Society in Washington to help unveil a strange new dinosaur discovery named Nigersaurus taqueti.

The 110-million-year-old plant-muncher had a skull “that only a mother could love,” said Paul Sereno, the University of Chicago paleontologist who found the fossils 10 years ago in Niger, a country in Western Africa. Its mouth was wider than its skull and contained as many as 500 tiny, sharp teeth that fell out almost monthly and were immediately replaced by another 500!

The bizarre creature — a life-size skeletal model is on display at National Geographic along with the actual fossils — is changing the view of dinosaurs as long-necked beasts that roamed Earth with heads held high. Nigersaurus, scientists say, was more like a grazing cow.

For Arieshae Parker, 14, learning “something new that no one else knows about” was the most exciting part of helping with the research. She belongs to Project Exploration, a group that Sereno and his wife set up to interest students, especially minorities and girls, in science careers.

Arieshae and the nine other kids who traveled to Washington knew the project was something big. Sereno told them that the 30-foot-long Nigersaurus was special because of its unique build, including a vacuum-like mouth, thin bones and walnut-size brain.

Many mysteries remain about Nigersaurus, including why it had such a long tail.

If Arieshae becomes a paleontologist, she might someday come up with the answer.