26ft-Long Dinosaur Bigger Than T. Rex Ancestor With Blade-Like Teeth Discovered

Researchers have helped identify a new prehistoric predator that dominated the evolutionary ancestor of the infamous Tyrannosaurus rex (T. rex) in terms of size. The dinosaur, which was five times the size of the T. rex ancestor which existed at the time, has been named Ulughbegasaurus and was identified from a fossilized jaw bone.

The creature lived 80 to 90 million years ago, long before the T.rex but alongside one of its smaller evolutionary predecessors, University of Calgary researchers, associate professor of paleontology Darla Zelenitsky, and Dr. Kohei Tanaka found. The fact that it was between 24.5 feet and 26 feet in length and weighed around 2,000 pounds means that it would have been the apex predator of that era of Earth's prehistory.

The predecessor to the T. rex species that walked the Earth at that time grew to only around 10 feet in length and weighed around 440 pounds (200 kilograms). That means that not only would Ulughbegasaurus have overwhelmed the that animal in competition for food, it likely held back the evolution of the smaller species.

"They probably kept the tyrannosaurus down, they were obviously better apex predators," Zelenitsky told The Calgary Herald. "It was like a grizzly bear compared to a coyote."

The T.rex that most of us are familiar with would not evolve for around another 25 million years.

"The ancestor is a genus called Timurlengia, a tyrannosaur that was under 200 kilograms (440 pounds) in body weight," she told Newsweek.

The sheer size wasn't the only advantage Ulughbegasaurus had that would have put it above the T. rex's ancestor in the prehistoric food chain, according to Zelenitsky. The apex predator's fossilized teeth show that the Ulughbegasaurus had slashing, blade-like teeth. Paleontologists can tell a lot about how an extinct animal lived from its teeth.

"The disappearance of [Ulughbegasaurus] likely allowed tyrannosaur species to become the apex predators of Asia and North America some 80 to 90 million years ago," Zelenitsky said.

This disappearance would have allowed the early T. rex to evolve into the dominant predator we know from the Jurassic Park franchise and other movies and TV shows. The later T. rex species would weigh between 11,000 and 15,000 pounds and grow to around 40 feet in length, thus outgrowing the Ulughbegasaurus considerably.

The fossilized jawbone that lead to the discovery was found by a Russian paleontologist in the 1980s in what was then known as the Soviet Central Asian Republic of Uzbekistan. Since its discovery, the jawbone fossil had sat in the Vernadsky State Geological Museum, Moscow, for years.

That was until it was transported to Calgary for further examination. This allowed Zelenitsky and Tanaka to use 3D modeling to discover that the jawbone belonged to a previously undiscovered species of dinosaur. An apex predator that researchers had spent years searching for.

"The apex predator was missing from the species and now here it is," said Zelenitsky. "I was surprised it took so long to identify such a large predator, so this is very exciting."

Correction 09/13/21, 11:47 a.m ET: This article was updated to clarify the Ulughbegasaurus was larger than an ancestor of the T. rex.

Update 09/14/21, 2:19 a.m. ET: This article was updated to include the name of the T.rex ancestor, Timurlengia.

T Rex
An illustration of T.rex. This prehistoric predator may have become top of the food chain, but its ancestor was dominated by the recently discovered Ulughbegasaurus, which was five times its size. Warpaintcobra/ iStock / Getty Images Plus/Getty