Mini T. Rex, Timurlengia Euotica, Proves Fearsome Dino Had Brains First, Brawn Later

Paleontologists have long wondered how the fearsome and gigantic Tyrannosaurus Rex became that way in such a short period of time. Now, they may have an answer thanks to the discovery of the predator’s early cousin, Timurlengia euotica.

Both T. Rex and Timurlengia euotica are in the same family of dinosaurs, the tyrannosaurs. The Timurlengia euotica is not an ancestor, though the two are so similar that scientists have called the new species a mini T-Rex, CBS News reported.

The T. Rex emerged in the Jurassic Era, about 170 million years ago, Smithsonian Science News added. Back then, they were 10 feet in length and graceful. By the end of the Cretaceous 100 million years later, they were behemoths — 40 feet long, six tons, and about the size of a tractor trailer.

Timurlengia euotica lived 90 million years ago and was about the size of a horse, the physical equivalent of the T. Rex ancestor. Timurlengia euotica were carnivores, too, described as a “nimble pursuit hunter with slender, blade-like teeth suitable for slicing through meat.”

Paleontologists believe that the super-predator evolved into its massive size in 10 million years, but they never figured out how it got from point A to point B, the Christian Science Monitor added. Timurlengia euotica lived right in the middle of a 20-million-year gap in the fossil record that kept those answers a mystery.

“[Timurlengia euotica] proved to be a really important member of the tyrannosaur family because it shows how these giant super predators came to be,” said Dr. Hans Sues of the Smithsonian National Museum of Natural History.

“We had long known that this linage goes back more than 100 million years… and we always wondered how relatively small animals like the early tyrannosaurs… had grown up to be super predators that were the size of a school bus and had the weight of a large African Bull elephant.”

When Timurlengia euotica was first found, it was called the “Rosetta Stone” of discoveries. From 1997 to 2006, scientists working in Uzbekistan unearthed thousands of fossils, but the game changed in 2004 when they found part of a skull. Later, it would be identified as a tyrannosaur, identified as a new species, and given the name Timurlengia euotica.

The T-Rex’s brain case was about the size of a basketball, while Timurlengia euotica’s was roughly grapefruit-sized. But the smaller skull and its inner ear structures are miniaturized versions of the larger. That led scientists to conclude that the heightened senses the huge predator was known for began with Timurlengia euotica.

“This fossil shows that tyrannosaurs developed their advanced head first,” Sues said. “Timurlengia’s skull, though much smaller than that of T. rex, shows a sophisticated brain that would have led to keen eyesight, smell and hearing.”

Scientists used to think that the dinosaur grew to massive proportions first, then evolved its smarts. But the fact that its predecessor also had a large and advanced brain and an ear attuned to low frequency sound suggests that this assumption was wrong. Paleontologists have developed a “head first” theory about T. Rex evolution thanks to Timurlengia euotica, said Dr. Stephen Brusatte.

“The tyrannosaur had to get smart before it got big.”

Millions of years before its opportunity to become Earth’s alpha predator, Timurlengia euotica set the stage and made it possible.

The creature gave the T. Rex its hypersensitive hearing and other tools that ultimately helped it evolve into a fearsome predator when the opportunity arose, Brusatte noted. As these senses and cognitive abilities were being developed, other large, carnivorous dinos were dying out.

“Tyrannosaurs already had the advanced sensory toolkits they would need to become the most feared predators on the planet and were primed and at the ready for taking over ecosystems when their competitors bit the dust,” said paleontologist Lindsay Zanno. “The truth is that tyrannosaurs were little more than understudies in ecosystems long dominated by other dinosaurian megapredators before seizing the opportunity to become the starring act themselves.”

[Photo by Susan Walsh/AP Photo]