N. America's Oldest Horned Dino Was Size of Bunny

When paleontologists on a National Geographic Society expedition dug up a 100-million-year-plus sample sticking out of the dirt in Montana in 1997, they initially thought it was a rock—until they saw it had teeth. Now, 17 years later, they've finally gotten around to naming and describing the creature, believed to be the oldest horned dinosaur ever found in North America, National Geographic reports. A study published this week in PLoS One introduces Aquilops americanus, a relative of the triceratops with an eagle-like face but a much smaller frame: Scientists believe the dino was about 2 feet long and weighed around 3.5 pounds, or "about as much as a large bunny rabbit." The skull bones point to a teen dinosaur, though scientists suspect the adult version wasn't significantly bigger.

"Imagine a Chihuahua beside a Great Dane," Cleveland paleontologist Michael Ryan tells National Geographic in describing the differences between Aquilops and its ceratopsian cousins. Ryan adds that this early Cretaceous animal didn't have the fancy neck frill the triceratops boasts or long brow horns: Instead, it's populated with plenty of tinier horns and a sharply hooked beak that leads scientists to infer it was a picky vegetarian. And because this fossil looks most like ceratopsians from Asia, it serves as an important clue regarding how dinosaurs migrated across the continents millions of years ago, Ryan explains. (Hopefully Aquilops met a kinder fate than that of this recently discovered dino.)