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Photos: Brainy, Horse-Size Tyrannosaur Discovered in Uzbekistan

T. Rex's Cousin Found

Uzbek tyrannosaur, tyrannosaur relative

(Image credit: Todd Marshall)

A horse-sized relative of the mighty Tyrannosaurus rex may not have been big, but it had a surprisingly advanced brain, a new study finds. The newfound dianosaur species, Timurlengia euotica, lived in what is now present-day Uzbekistan during the Cretaceous, about 90 million years ago. An analysis of its braincase showed that it had extraordinary low-frequency hearing, which likely helped it hunt prey. It may not have been the size of T. rex, but T. euotica provides evidence that tyrannosaurs' complex brains likely helped them become apex predators during the dinosaur age. [Read the Full Story on the Brainy Tyrannosaur]

Uzbek tyrannosaur

Uzbek tyrannosaur, tyrannosaur relative

(Image credit: Todd Marshall)

This illustration shows T. euotica prowling around Central Asia about 90 million years. Back then, the Central Asian climate was less like a desert, and more forested with rivers and lakes, said study lead researcher Steve Brusatte, a paleontologist at the University of Edinburgh in the U.K.

Dinosaur skeleton

Dinosaur skeleton, tyrannosaur relative

(Image credit: Todd Marshall and Steve Brusatte)

T. euotica's skeleton, with the bones that paleontologists discovered highlighted in red. Until now, there were no known tyrannosaur fossils from the mid-Cretaceous. This newfound horse-size specimen shows that tyrannosaurs were still relatively small about 90 million years ago.

Family tree

Family tree, tyrannosaur relative

(Image credit: Steve Brusatte)

T. rex has made the fierce dinosaurs known as tyrannosaurs immensely popular, but little is known about their family tree. Notice that T. euotica is the only known tyrannosaur rom the mid-Cretaceous. It was larger than the human- and dog-size tyrannosaurs from earlier time periods, but it was nowhere near the size of T. rex. This suggests that tyrannosaurs didn't get humongous until the last 20 million years of their evolution, Brusatte said.

In a recent study, Brusatte and Thomas Car, an associate professor of biology at Carthage College in Wisconsin (who was not involved in the new study), created this family tree. Their findings suggest that T. rex, which lived from about 67 million years ago, was an invasive species from Asia.

Incredible brain

Incredible brain, tyrannosaur relative

(Image credit: Steve Brusatte)

T. euotica's braincase — the part of the skull that holds the brain — was incredibly well- preserved, Brusatte said.

Skull scan

skull scan, tyrannosaur relative

(Image credit: Steve Brusatte)

Study senior author Ian Butler, a research fellow in experimental geosciences at the University of Edinburgh, uses computer tomography (CT) to scan the skull of T. euotica.

Digital analysis

Digital analysis, tyrannosaur relative

(Image credit: Amy Muir and Steve Brusatte)

A CT reconstruction shows what the inner part of the dinosaur's ear, nerves and vessels would have looked like.

Long cochlea

Long cochlea, tyrannosaur relative

(Image credit: Amy Muir and Steve Brusatte)

Another CT reconstruction of T. euotica's brain. Notice the long cochlea duct, shown in pink. A long cochlea duct suggests that the dinosaur could hear low frequencies, which likely helped it hunt prey.

Paleontologist party

Paleontologist party, tyrannosaur relative

(Image credit: Courtesy of H-D Sues)

Study co-authors and paleontologists Alexander Averianov (left) and Hans-Dieter Sues (right), who led the group that discovered the newfound tyrannosaur in Uzbekistan.

Dino duo

Dino duo, tyrannosaur relative

(Image credit: Courtesy of Steve Brusatte)

Paleontologists and study researchers Alexander Averianov (left) and Steve Brusatte (right). Averianov and Sues asked Brusatte to join the study because he had experience studying dinosaur braincases of tyrannosaurs and theropods (bipedal, mostly meat-eating dinosaurs).

T. euotica's stomping ground

T. euotica's stomping ground, tyrannosaur relative

(Image credit: Igor Danilov)

The region in Uzbekistan where the researchers did the dinosaur fieldwork.