Fossils of the skull from the new species.

AUSTIN (KXAN) — Fossils a professor unearthed in Big Bend National Park 35 years ago are now classified as a new species of duck-billed dinosaur called Aquilarhinus palimentus, according to a press release from the National Park Service.

Illustrations of the new species of dinosaur, the duck-billed Aquilarhinus palimentus at Big Bend National Park. (Image from ICRA via National Park Service)

Texas Tech University Professor Tom Lehman originally discovered the fossils in the 1980s, but they were badly weathered and stuck together, making it difficult for scientists to study.

In the 1990s, researchers revealed the fossils displayed two arched nasal crests that were thought to be distinctive of the Gryposaurus genus. However, recent analysis led researchers to realize the animal they were studying was more primitive than Gryposaurus or anything else they’d seen before.

The duck-billed dinosaur has a curved, aquiline nose and wide jaw shaped like two trowels laid side by side.

Fossils of the skull from the new species.

Duck-billed dinosaurs were the most common herbivorous dinosaurs at the end of the Mesozoic Era and all had a similar-looking snout. Unlike other duck-billed dinosaurs of the time, the Big Bend fossils display a very distinct W-shaped lower jaw that created a wide, flattened scoop.

“Around 80 million years ago, this particular dinosaur would have been shoveling through loose, wet sediment to scoop loosely-rooted aquatic plants from the tidal marshes of an ancient delta, where today lies the Chihuahuan desert,” officials wrote.

Illustrations of the new species of dinosaur, the duck-billed Aquilarhinus palimentus, at Big Bend National Park. (Image from ICRA via National Park Service)

For scientists, the discovery is a significant one because it now suggests there might have been more primitive species in the region than they previously thought. They recently published their findings in the Journal of Systematic Paleontology.

The Aquilarhinus palimentus specimen is housed at the Texas Vertebrate Paleontology Collections at the University of Texas at Austin.