A fossil from the oldest horned dinosaur ever discovered in North America was recently discovered by paleontologists. The dinosaur, roughly the size of a house cat, is 15 million years older than its previously recognized horned ancestors.

The dinosaur’s fossilized skull and jaw were initially found by  Scott Madsen in 1997 in Montana. It wasn’t until recently that paleontologists returned to the fossil.

Andrew Farke, a paleontologist with Raymond M. Alf Museum of Paleontology, said in a statement, “Up to this point, all that was known for horned dinosaurs were just isolated teeth and fragment bones. This new find is the first one that allows us to say exactly what kinds of horned dinosaurs lived in North America about 108 million years ago.” He explained that Madsen initially believed the fossil belonged to a common plant-eating dinosaur.

The dinosaur, known as aquilops americanus, lived during the earlier part of the Cretaceous period, which spanned from 145.5 million to 65.5 million years ago. Horned dinosaurs thrived during this time, as did various groups of insects, modern mammals, and groups of birds. It is believed that an asteroid ultimately ended this period after striking Earth.

The herbivore measured approximately two feet in length and weighed nearly 3.5 pounds, making it small enough to comfortably hold in one’s arms.

The discovery of these bones is significant not only because they indicate that this type of animal lived in North America earlier than initially thought, but they might also give insight into how the animals arrived on the continent.

According to the paper, published in PLOS One, the dinosaur probably originated via a dispersal from Asia into North America; the exact route of this dispersal is ambiguous, although a Beringian rather than European route seems more likely in light of the absence of ceratopsians in the Early Cretaceous of Europe.