A fossilized skull was recently unearthed in Montana, the oldest horned dinosaur from the Early Cretaceous in North America, a new study finds.

"Aquilops lived nearly 20 million years before the next oldest horned dinosaur named from North America," lead author Andrew Farke, a paleontologist at the Raymond M. Alf Museum of Paleontology in California, said in a statement.

There is limited fossil evidence of neoceratopsian, or horned dinosaurs, dating back to 113-105 million years ago, so the discovery of Aquilops americanus, however small, promises to shed some light on these poorly understood creatures.

"One thing paleontologists have been doing lately is trying to figure out where the late Cretaceous dinosaurs came from," Lindsay Zanno, an assistant research professor of paleontology at North Carolina State University, who was not involved in the study, told Live Science. "Did they get to North America or did they evolve here?"

According to the new findings, published in the journal PLOS ONE, the species likely migrated to the continent from Asia on an ancient land bridge across the Pacific Ocean.

The A. americanus specimen, measuring a mere 84 millimeters long, has distinguished features that include a hooked beak and sharply pointed cheeks. Fossil evidence indicates that the herbivore's beak likely helped it pluck vegetation from trees and plants, and its sharp, protruding cheekbones kept predators at bay - or was just decorative.

And although it doesn't actually have the characteristic horns, it is indeed a neoceratopsian, researchers say.

"It's from the time before horned dinosaurs became horned," Farke added.

When people think about dinosaurs in North America, Triceratops or the feared Tyrannosaurus rex, which are from the Late Cretaceous, come to mind. Few would every think of smaller reptiles, specifically the crow-sized Aquilops, which was first found at the Cloverly Formation in Montana in 1997.

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