Dino card No. 0394 of 2,015

Chasmosaurus

Say it: KAZ-mo-SORE-us

Name means: “opening lizard, referring to the large openings in its frill”1

Ate: PlantsHorned dinosLate Cretaceous

Chasmosaurus was a plant-eating dinosaur with a huge bony frill on its head. It lived in what is now Canada and the USA during the Late Cretaceous period, about 77 to 74 million years ago. It was smaller than its famous relative Triceratops, but still weighed as much as a car.1

Lived

84 to 72 million years ago2

Late Cretaceous

Fossils found in

Alberta, Canada and Montana, USA1 2

Food

Plants2

Length

4.3 to 4.8 m1

Weight

1.5 tonnes to 2 tonnes1

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

cool stuff

Fun facts

The name Chasmosaurus means 'opening lizard' because its frill had huge holes, called fenestrae, that made it lighter.1

It was first named Protorosaurus, but that name was already used for another reptile, so it was changed to Chasmosaurus in 1914.1

Some scientists think that Chasmosaurus lived alongside other horned dinosaurs like Centrosaurus, but they probably ate different plants to avoid competing.1

Fossils of Chasmosaurus include skin impressions, which are very rare and help scientists understand what its skin looked like.1

One specimen, ROM 843, is a nearly complete skeleton that shows how the dinosaur was built.1

Chasmosaurus had a short nose and a beak, and its frill was probably used for display or to attract mates.1

AI-made picture of Chasmosaurus — An AI-made picture of how Chasmosaurus might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

Myth buster

Myth: Some people think Chasmosaurus was a type of Triceratops.

Truth: Chasmosaurus was a different genus of ceratopsid dinosaur, with a much larger frill and smaller horns than Triceratops.1

For dino experts

Scientific name: Chasmosaurus
Named by: Lambe 19142
Group: Horned dinos
Family / clade: Ceratopsidae2
Classification: Ornithischia > Ceratopsia > Ceratopsidae2
Age of the rocks: 84 to 72 million years (Campanian)2
Rock formations: Dinosaur Park, Oldman, Judith River2
Countries: Canada, USA2
Fossil records: 21 in the Paleobiology Database2
Also known as: Eoceratops, Mojoceratops, Protorosaurus (older names now counted as the same animal)2
Discovery: The first Chasmosaurus fossil was found in 1898 by Lawrence Lambe in Alberta, Canada. He named it Monoclonius belli at first, but later changed the name to Chasmosaurus in 1914.1
Still debated: Scientists still debate whether some fossils belong to Chasmosaurus or to a separate genus called Mojoceratops.1 2

Where the facts come from

Chasmosaurus (en.wikipedia.org)
Chasmosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at hello@dinowiki.app and we will fix it.