Dino card No. 0761 of 2,027

Gualicho

Say it: gwah-LEE-cho

Name means: “named after the gualichu, a demon from local folklore”1

Ate: MeatTyrannosaursEarly Cretaceous

Gualicho was a medium-sized meat-eating dinosaur that lived in what is now Argentina. It had very short arms with only two fingers, a bit like a tiny T. rex! Scientists are still arguing about which group of theropods it belongs to.1 2

Lived

110 to 106 million years ago4

Early Cretaceous

Fossils found in

Río Negro Province, northern Patagonia, Argentina1 2

Food

Meat4

Length

6 to 7 m1

estimate

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 7 dogs nose to tailas long as 39 bananas end to end

How big was Gualicho compared to YOU?

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cool stuff

Fun facts

Gualicho had only two fingers on each hand. The third finger was reduced to a tiny splint of bone.1 2

Its arms were very short, similar to the arms of Tyrannosaurus rex. This is an example of convergent evolution.1 2

The fossil was discovered on February 13, 2007, by Akiko Shinya, a preparator from the Field Museum of Natural History.1

Gualicho lived about 106 million years ago during the Early Cretaceous period.1

The skeleton was found in the Huincul Formation, which also produced the giant sauropod Argentinosaurus and the huge predator Mapusaurus.2

Scientists are not sure if Gualicho is a type of allosauroid or a tyrannosauroid. Different studies place it in different groups.1 4

The name Gualicho comes from a demon in the folklore of the Tehuelche people of Patagonia.1 2

AI-made picture of Gualicho — An AI-made picture of how Gualicho 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 Gualicho

?How big was Gualicho?

About 6 to 7 metres long. It weighed around 450 kilograms, which is about as much as a large polar bear.1 3

?Did Gualicho have feathers?

Nobody knows for sure. No feathers were found with the fossil, and it is not closely related to known feathered dinosaurs.1

?What did Gualicho eat?

It was a meat-eater, like other theropod dinosaurs. It probably hunted smaller animals or scavenged.1

?Why did Gualicho have short arms?

Scientists are not sure. Its arms were very short with only two fingers, similar to T. rex, but this evolved separately.3

?Is Gualicho a dinosaur?

Yes, it is a theropod dinosaur. It lived about 106 million years ago in what is now Argentina.1

?Was Gualicho bigger than T. rex?

No, it was much smaller. Gualicho was about 6 to 7 metres long, while T. rex could reach over 12 metres.1

Ask Rex about Gualicho

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Myth buster

Myth: Gualicho is a small relative of Tyrannosaurus rex.

Truth: Gualicho is not a close relative of T. rex. It is probably an allosauroid, a different branch of meat-eating dinosaurs. Its two-fingered hands evolved separately.1 2

For dino experts

Scientific name: Gualicho
Named by: Apesteguia et al. 20164
Group: Tyrannosaurs
Family / clade: Tyrannosauroidea4
Classification: Theropoda > Tyrannosauroidea4
Age of the rocks: 110 to 106 million years (Albian)4
Rock formations: Huincul4
Countries: Argentina4
Fossil records: 1 in the Paleobiology Database4
Discovery: The only known fossil of Gualicho was found in 2007 by Akiko Shinya at a site called Violante's field in Argentina. It was named and described in 2016 by Sebastián Apesteguía and colleagues.1 2
Still debated: Scientists debate whether Gualicho is an allosauroid or a tyrannosauroid. Its exact place on the dinosaur family tree is still uncertain.1 4

Where the facts come from

Gualicho (en.wikipedia.org)
An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina (journals.plos.org)
Newly-discovered dinosaur had “T. rex arms” that evolved independently - Field Museum (fieldmuseum.org)
Gualicho 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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