Dino card No. 0068 of 2,015

Alectrosaurus

Say it: al-LEK-troh-SORE-us

Name means: “alone lizard”1

Ate: MeatTyrannosaursLate Cretaceous

Alectrosaurus was a medium-sized, meat-eating dinosaur that lived in Asia during the Late Cretaceous. It was an early relative of the famous Tyrannosaurus rex, but smaller and more lightly built. Scientists have mostly found its leg and foot bones, so they are still learning what the rest of it looked like.1

Lived

100 to 72 million years ago2

Late Cretaceous

Fossils found in

Inner Mongolia, China; also reported from Uzbekistan, Kazakhstan, and Tajikistan2 1

Food

Meat2

Length

5 to 6 m1

estimated

Artist's life restoration of Alectrosaurus — How Alectrosaurus may have looked, by ABelov2014. CC BY 3.0, via Wikimedia Commons. Scientists still argue about colours and details.

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

cool stuff

Fun facts

Alectrosaurus means 'alone lizard' because when it was first discovered, scientists thought it was a unique type of dinosaur.1

The only known skeleton of Alectrosaurus is mostly a hind leg and some foot bones. No complete skull has been found yet.1

Alectrosaurus had a special foot feature: the ends of its toe bones were swollen and raised up like little pedestals. Scientists call this the 'pediculate' condition.1

It lived about 90 to 83 million years ago, during the Coniacian to Campanian stages of the Late Cretaceous.1

Alectrosaurus was a tyrannosauroid, which means it was an early cousin of Tyrannosaurus rex, but much smaller and more slender.1

Some fossils from Uzbekistan and Mongolia were once thought to be Alectrosaurus, but scientists now think those bones belong to other, unknown tyrannosaurs.1

For dino experts

Scientific name: Alectrosaurus
Named by: Gilmore 19332
Group: Tyrannosaurs
Family / clade: Tyrannosauroidea2
Classification: Theropoda > Tyrannosauroidea2
Age of the rocks: 100 to 72 million years (Cenomanian to Campanian)2
Rock formations: Bissekty, Iren Dabasu, Khodzhakul2
Countries: Uzbekistan, Kazakhstan, China, Tajikistan2
Fossil records: 19 in the Paleobiology Database2
Discovery: Alectrosaurus was named by American paleontologist Charles W. Gilmore in 1933. The first fossils were found in the Iren Dabasu Formation in Inner Mongolia, China, during the Third Asiatic Expedition.2 1
Still debated: Scientists are not sure what the skull of Alectrosaurus looked like, because no skull bones have been found that definitely belong to it.1

Where the facts come from

A reappraisal of tyrannosauroid fossils from the Iren Dabasu Formation (Coniacian, Campanian), Inner (dinodata.de)
Alectrosaurus 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.