SCIENCE

A tiny horned skull discovered 17 years ago has now been named Aquilops americanus, and marks the earliest arrival of horned dinosaurs in North America. (Nat Geo News)

Use this map to learn more about Aquilops and the rest of “North America in the Age of the Dinosaurs.”

Teachers, scroll down for short list of key resources in our Teachers’ Toolkit.

Discussion Ideas

• Look at our beautiful map of North America 74 million years ago. In particular, take a look at the “Dinosaur Fossil Distribution” legend off the West Coast. What symbol would you use to indicate the Aquilops americanus discovery (really, an identification of an earlier discovery)? Read the Nat Geo article on Aquilops for some help.
  • The Aquilops americanus fossil was dated to the Early Cretaceous. Fossils from the Early Cretaceous are indicated with a hollow hexagon.

• Using the same high-res map, where would you place your symbol for the Aquilops americanus fossil? Are there any other fossils from the Aquilops time period nearby?
  • According to the PLoS ONE study, the Aquilops americanus fossil was discovered in southern Montana.
  • As of 1993, when the map was published, there was one other site in southern Montana where Early Cretaceous dinosaurs have been identified.

• Read the map legend about ceratopsians, at the top of the map. Why do you think the map nicknames this group of dinosaurs the “Rhino Dinos”?
  • This is a rhino.

    

  • And this is a (ceratopsian) dino.

    

     

• Review the map legend about ceratopsians, at the top of the map. According to the map, Triceratops and other ceratopsians “appear to have been the most numerous of [North America’s] dinosaurs.” So, what makes Aquilops so special?
  • Age. Aquilops is the oldest ceratopsian discovered in North America, having lived more than 100 million years ago. Triceratops went extinct (along with about three-quarters of life on Earth!) about 66 million years ago.
  • Size. Aquilops is much smaller than most ceratopsians. Triceratops reached about 9 meters (30 feet) in length and weighed about 6 tons (13,000 pounds)—about the size of a bus. Aquilops was less than a meter (2 feet) long and weighed about 1.6 kilograms (3.5 pounds)—”about as much as a large bunny rabbit,” according to one paleontologist.
  • Physical characteristics. Aquilops looks different than other ceratopsians. It has an oddly shaped beak, for one.”‘The shape is unlike any other one in how strongly hooked it is,’ says one paleontologist, which may be a clue that Aquilops was a choosy feeder that browsed on a relatively limited menu of Cretaceous vegetation.” Aquilops also lacks the characteristic frill (wide plate over the neck) and enormous brow horns of Triceratops.

• According to the Nat Geo News article, Aquilops’ closest known relatives lived in Asia. Take a look at map of Earth, 100 million years ago—just a little while (geologically speaking) after Aquilops was lopping around. Besides North America and Asia, where else do you think similar ceratopsian fossils may be found?

  

  • Ceratopsian fossils have been discovered in Europe. (Meet Ajkaceratops, for example, from Hungary.) All three continents were taking shape 100 million years ago, and were part of one weird landmass. (To be fair, continents are still taking shape, and they are still weird landmasses: North America, Asia, Europe.)

TEACHERS’ TOOLKIT

Nat Geo: Bunny-Sized Dinosaur Was First of Its Kind in America

Nat Geo: 1993 North America in the Age of the Dinosaurs

(extra credit!) PLoS One: A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America, and the Biogeography of Neoceratopsia