Dino card No. 0019 of 2,027

Acristavus

Say it: a-KRIS-ta-vus

Name means: “crestless grandfather”1

Ate: PlantsDuck-billsLate Cretaceous

Acristavus was a duck-billed dinosaur that lived about 80 million years ago. It had no crest on its head, which is unusual for its family. This plant-eater walked on two legs and could also move on all fours.1 2

Lived

84 to 72 million years ago5

Late Cretaceous

Fossils found in

Montana and Utah, USA5

Food

Plants1 2

Length

8 to 9 m1

estimated

Weight

2 tonnes to 3 tonnes1

Height

2.5 to 3 m1

at the hips

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

as long as 2 cars parked in a rowas long as 50 bananas end to endas heavy as 2 carsas heavy as 100 big dogsas heavy as 600 watermelonsas tall as 1.5 doors stacked up

How big was Acristavus compared to YOU?

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cool stuff

Fun facts

Acristavus means 'crestless grandfather' because it is one of the oldest known duck-billed dinosaurs without a head crest.1

Its fossils were found in the Two Medicine Formation of Montana and the Wahweap Formation of Utah.5

Acristavus lived during the Campanian stage of the Late Cretaceous, about 83 to 72 million years ago.1

It belonged to a group called Brachylophosaurini, which includes other duck-billed dinosaurs like Brachylophosaurus.1

The type specimen, named MOR 1155, is a partial skeleton that helped scientists identify this species.5

Acristavus was a ground-dwelling herbivore that laid eggs, like all duck-billed dinosaurs.2

AI-made picture of Acristavus — An AI-made picture of how Acristavus 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.

you asked

Most asked questions about Acristavus

?How big was Acristavus?

Scientists have not published a full size estimate yet, but as a hadrosaur it was probably around 8 to 9 metres (26 to 30 ft) long, about as long as a school bus.3 5

?Did Acristavus have a crest?

No. Acristavus is special because it had no crest or ornamentation on its skull, unlike most other duck-billed dinosaurs.3 4

?What did Acristavus eat?

Acristavus was a plant-eater (herbivore). It ate ferns, leaves and other plants that grew in its wet, seasonal habitat.5 3

?When did Acristavus live?

Acristavus lived about 79 to 81 million years ago, during the Campanian stage of the Late Cretaceous.3 5

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For dino experts

Scientific name: Acristavus
Named by: Gates et al. 20115
Group: Duck-bills
Family / clade: Hadrosauridae5
Classification: Ornithischia > Ornithopoda > Iguanodontia > Hadrosauridae5
Age of the rocks: 84 to 72 million years (Campanian)5
Rock formations: Two Medicine, Wahweap5
Countries: USA5
Fossil records: 2 in the Paleobiology Database5
Discovery: Acristavus was named by Terry A. Gates, Jack Horner, and colleagues in 2011. The first fossils were found in Montana and Utah.1
Still debated: Scientists are not sure why Acristavus lacked a head crest while many other duck-billed dinosaurs had one.1

Where the facts come from

PBDB Taxon (paleobiodb.org)
Acristavus Gates et al. 2011 - Encyclopedia of Life (eol.org)
Acristavus (Wikipedia) (Wikipedia)
Acristavus: North America’s New Hadrosaur (smithsonianmag.com)
Acristavus 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 [email protected] and we will fix it.

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