Oldest Horned Dinosaur Species in North America is the Size of a Crow

During the early Cretaceous in North America, a horned dinosaur species stalked the forests. Now, scientists have taken a closer look at this newly discovered species, and have revealed that it's the first definite horned dinosaur species from that period.

There's a limited fossil record for neoceratopsian-or horned dinosaurs-from the Early Cretaceous in North America. This, in turn, limits scientists' ability to reconstruct the early evolution of this group of dinosaurs. Yet a new finding may shed a bit of light on these dinosaurs.

The researchers unearthed a fossil dinosaur skull in Montana that represents the first horned dinosaur from the North American Early Cretaceous that they can identify to the species level. The dinosaur itself is now named Aquilops americanus, and it closely resembles similar species in Asia.

The dinosaur itself was relatively small. In fact, the skull measures just 84 mm long. It's distinguishable by several features, including a strongly hooked rostral bone-or beak-like structure-and an elongated and sharply pointed cavity over the cheek region. When this particular dinosaur was alive, it was only about the size of a crow.

"Aquilops lived nearly 20 million years before the next oldest horned dinosaur named from North America," said Andrew Farke, one of the researchers, in a news release. "Even so, we were surprised that it was more closely related to Asian animals than those from North America."

This latest discovery, combined with neoceratopsian fossils from other locations, reveal that it's likely that there was a late Early Cretaceous intercontinental migratory event between Asia and North America. In other words, these horned dinosaurs traveled between continents. That said, scientists still need to conduct additional fieldwork in order to better reconstruct the timing and mode of these migrations.

The findings are published in the journal PLOS One.

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