Dino card No. 1535 of 2,027

Raptorex

Say it: rap-TOR-ex

Name means: “robber king”1

Ate: MeatTyrannosaursEarly Cretaceous to Late Cretaceous

Raptorex was a tiny cousin of T. rex that lived about 70 million years ago. It had a big head, long legs for running, and tiny arms with just two fingers. Even though it was small, it already looked like a mini version of the giant tyrannosaurs!1

Lived

126 to 66 million years ago4

Early Cretaceous to Late Cretaceous

Fossils found in

Mongolia (probably Nemegt Formation)1

Food

Meat4

Length

2.5 to 3 m1

juvenile specimen; adult size unknown

Weight

65 kg1

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How heavy was it?

as heavy as 2 big dogs

as long as 3 dogs nose to tailas long as 17 bananas end to endas heavy as 13 watermelons

How big was Raptorex compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

cool stuff

Fun facts

Raptorex is known from just one skeleton, which is a very young juvenile about three years old.1

Its tiny arms and big head are features that scientists once thought only appeared in giant tyrannosaurs, but Raptorex shows they evolved in small dinosaurs first.2

Many scientists now think Raptorex might actually be a baby Tarbosaurus, a close relative of T. rex from Mongolia.1

The only Raptorex fossil was bought at a gem and mineral show in Arizona before a scientist studied it.1

A fish bone found with the Raptorex skeleton helped scientists figure out that it probably came from the Late Cretaceous Nemegt Formation in Mongolia.1

Raptorex was about the size of a large dog, only 2.5 to 3 metres long and weighing around 65 kilograms.1

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

?How big was Raptorex?

About 2.5 to 3 metres (8.2 to 9.8 feet) long and weighed around 65 kilograms (143 pounds), about the size of a large human.1

?Was Raptorex a dinosaur?

Yes, Raptorex was a small tyrannosaurid dinosaur, a close cousin of T. rex.1

?Did Raptorex have feathers?

The sources don't say for sure, but many small tyrannosaurs had feathers. Since Raptorex was a juvenile, it might have had a light covering of feathers, but no direct evidence is known.1

?What did Raptorex eat?

Raptorex was a meat-eater, like other tyrannosaurs. It probably hunted small animals or scavenged, using its big head and sharp teeth.1

?Is Raptorex a baby Tarbosaurus?

Many scientists now think Raptorex might be a juvenile Tarbosaurus, a close relative of T. rex from Mongolia, because the only skeleton looks just like a baby Tarbosaurus.1 3

?When did Raptorex live?

It probably lived about 70 million years ago, during the Late Cretaceous period, in what is now Mongolia.1

Ask Rex about Raptorex

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Myth buster

Myth: Some people think Raptorex is a separate species that lived in the Early Cretaceous, about 125 million years ago.

Truth: Scientists now agree that Raptorex is a juvenile tyrannosaur from the Late Cretaceous, about 70 million years ago, and it may be the same as Tarbosaurus.1

For dino experts

Scientific name: Raptorex
Named by: Sereno et al. 20094
Group: Tyrannosaurs
Family / clade: Tyrannosauroidea4
Classification: Theropoda > Tyrannosauroidea4
Age of the rocks: 126 to 66 million years (Barremian / Maastrichtian)4
Countries: China4
Fossil records: 1 in the Paleobiology Database4
Discovery: The only Raptorex fossil was bought by Dr. Henry Kriegstein at a fossil show in Tucson, Arizona. He showed it to paleontologist Paul Sereno, who named it Raptorex kriegsteini in 2009.1
Still debated: Scientists still argue whether Raptorex is a valid genus or just a baby Tarbosaurus. More fossils are needed to settle the debate.1

Where the facts come from

Raptorex (en.wikipedia.org)
Becoming T. rex | Science (science.org)
Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia | PLOS One (journals.plos.org)
Raptorex 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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