Dino card No. 1716 of 2,027

Stokesosaurus

Say it: STOH-kee-oh-SORE-us

Name means: “Stokes' lizard”1

Ate: MeatTyrannosaursLate Jurassic to Early Cretaceous

Stokesosaurus was a small, early cousin of the mighty T. rex. It lived during the Late Jurassic period, about 150 million years ago, in what is now the United States. This speedy predator hunted small animals in a world full of giant sauropods and Allosaurus.1

Lived

155 to 143 million years ago3

Late Jurassic to Early Cretaceous

Fossils found in

Utah, Colorado, Wyoming, and South Dakota, USA3 2

Food

Meat3

Length

2.5 to 4 m1

estimates vary; the holotype is a juvenile

Weight

60 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 4 dogs nose to tailas long as 22 bananas end to endas heavy as 12 watermelons

How big was Stokesosaurus compared to YOU?

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cool stuff

Fun facts

Stokesosaurus is one of the earliest known tyrannosauroids, the group that later included T. rex.1

The only certain fossil of Stokesosaurus is a single hip bone (ilium) from a juvenile, about 22 centimeters (8.7 inches) long.1

Stokesosaurus lived alongside giants like Allosaurus, which made up 70 to 75 percent of the big predators in its environment.1

A tiny ilium from South Dakota may belong to Stokesosaurus, showing it lived far from Utah.2

Some scientists think Stokesosaurus might be the same animal as Tanycolagreus, but the missing hip bone of Tanycolagreus makes this hard to check.1

Stokesosaurus was named after geologist William Lee Stokes, who helped dig up thousands of Allosaurus bones at the Cleveland-Lloyd Quarry.1

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

?How big was Stokesosaurus?

Stokesosaurus was a small dinosaur, about 3 to 4 meters long. One scientist estimated it at 2.5 meters and 60 kilograms.1

?What did Stokesosaurus eat?

It was a small, bipedal predator that likely ate small animals like lizards, early mammals, and maybe baby dinosaurs.1

?Where did Stokesosaurus live?

It lived in what is now Utah, USA, during the Late Jurassic period. A tiny hip bone from South Dakota might also belong to it, showing it lived farther east.1 2

?Is Stokesosaurus a dinosaur?

Yes, it is a theropod dinosaur, part of the group that includes T. rex and birds.1 3

?When did Stokesosaurus live?

It lived about 150 million years ago, during the Late Jurassic period (Tithonian stage).1

?Why is it called Stokesosaurus?

It is named after geologist William Lee Stokes, who helped dig up many Allosaurus bones at the Cleveland-Lloyd Quarry in Utah.1

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Myth buster

Myth: Some people think Stokesosaurus was a species of the British dinosaur Iliosuchus.

Truth: Scientists now agree Stokesosaurus is a separate genus, not a type of Iliosuchus.1

For dino experts

Scientific name: Stokesosaurus
Named by: Madsen 19743
Group: Tyrannosaurs
Family / clade: Tyrannosauroidea3
Classification: Theropoda > Tyrannosauroidea3
Age of the rocks: 155 to 143 million years (Kimmeridgian / Tithonian)3
Rock formations: Morrison3
Countries: USA3
Fossil records: 6 in the Paleobiology Database3
Discovery: Stokesosaurus was named in 1974 by James Henry Madsen, who found its hip bone among many Allosaurus fossils at the Cleveland-Lloyd Dinosaur Quarry in Utah.1
Still debated: Scientists are not sure if Stokesosaurus is the same as Tanycolagreus, because the key hip bone of Tanycolagreus has never been found.1

Where the facts come from

Stokesosaurus (en.wikipedia.org)
geology.byu.edu (geology.byu.edu)
Stokesosaurus 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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