T. Rex's recently discovered cousin was a killer the size of a pint

Paleontologists have identified a near unknown of T. rex who was standing just under 3 feet at the hip. This discovery sheds new light on the evolving origins of tyrannosaurs, while offering a glimpse of these fearsome creatures before they reach huge heights.

The new research published today in Nature Ecology & Evolution describes Suskityrannus hazelae, a tyrannosauroid dinosaur species. This creature lived during the Middle Cretaceian some 92 million years ago, or about 27 million years before the rise of the Tyrannosaurus rex. Suskityrannus is not a direct ancestor of T. rexbut his discovery fills a critical gap in the fossil record of tyrannosauroid dinosaurs, as only a few species of tyrannosauroids are known between the lower Cretaceous and the upper Cretaceous.

A quick note on the terminology. All tyrannosaurs are tyrannosaurs, but not all tyrannosaurs are tyrannosaurs; the group of Tyrannosaurus Dinosaurs is in the larger Tyrannosaurus group. Gigantic tyrannosaurs such as T. rex and Albertosaurus are tyrannosaurs. The authors of the new study, led by paleontologist Sterling Nesbitt of Virginia Tech, ranked Suskityrannus as a Tyrannosauroid tyrannosauroid. However, this new dinosaur is special is that it is more closely related to the T. rex and other tyrannosaurs than other lower Cretaceous tyrannosaurs.

The name Suskityrannus hazelae is derived from the local word Zuni for coyote, from the Latin word "tyrannus" which means king, and from the name Hazel Wolfe, supporter of the fossil expedition to New Mexico.

Suskityrannus It measured approximately 2.7 to 3.6 meters long, 0.6 to 0.9 meters to the hips and weighed no more than 40 kilograms. His skull was about 12 centimeters (32 centimeters) long. To put the size of this creature into perspective, it was just a little longer than an adult's skull. T. rex.

The newly described species is known through a pair of juvenile skeletons, found 50 meters apart in the Zuni Basin in New Mexico. The first skeleton was discovered in 1997 by Robert Denton, currently a geologist at Terracon Consultants. The second, more complete, skeleton was discovered by Nesbitt in 1998. Remarkably, Nesbitt was a 16-year-old high school student at the time. He found the bones during a paleontological expedition led by Doug Wolfe, co-author. of the new study and a paleontologist at the Institute of Zuni Dinosaur Geosciences.

For years, scientists did not know what they were facing, believing that the remains belonged to a kind of dromaeosaur, like a Velociraptor.

"We did not know that these fossils represented a tyrannosaur for more than ten years after their discovery," Nesbitt told Gizmodo in an email. "It was after discovering many small tyrannosaurs from China and North America that we were able to compare our specimen to those of others."

And indeed, the discovery links older and smaller tyrannosaurs from North America and China to the enormous tyrannosaurs that emerged during the Late Cretaceous.

"Suskityrannus helps us limit the time when big tyrannosauroid dinosaurs grew up – some time later, about 92 million years ago – and became the biggest meat consumers at the time, "said Nesbitt "More broadly, the tyrannosauroids date back to the Middle Jurassic, about 160 million years ago, but it was only at the end of the Cretaceous that they took over. 39; scale.

Nesbitt said the new dinosaur filled a major evolution gap, but it would be a mistake to call it a "missing link". Suskityrannus "Represents a side branch of [tyrannosauroid] family "and is not" a direct ancestor "of T. rex and other big tyrannosaurs, he said.

With respect to its unique physical characteristics, the biped Suskityrannus had long feet, a sharp bite and sharp and sharp teeth, characteristic of a fast-moving carnivore. He probably lived in a wet and swampy environment and feasted on hadrosaurs, ankylosaurs and other prey, according to Nesbitt.

A decent part of the skeleton was represented in both specimens, but parts of his skull, hands, and feet were missing. Scientists do not know if Suskityrannus had small arms like T. rex or if she had two or three fingers.

In an email to Gizmodo, paleontologist Thomas Carr of Carthage College said that one of the additional strengths of the new study is that Suskityrannus is represented by "more than a wand skeleton." The discovery is important, he said, because it reduces the time gap between small medium-sized tyrannosaurs and big ones. But that still means that there is a lag of 12 million years between "the first big tyrannosaurus and the ancestral representatives of the two main stocks of the giants, namely the lineage Albertosaurus and the tyrannosaurine lineage," he said. Carr, who is involved in the new study.

For Brownita doctoral candidate Armita Manafzadeh, who is also not affiliated with the new work, the most interesting aspect was the "arctometatarsalien" foot, which she says is "secretly the most exciting part of this article ".

"In an arctometatarsal foot, the three long bones that make up the sole of the foot are pinched together, the middle bone being particularly lean. Most dinosaurs and other reptiles have a roughly cylindrical sole like us, "wrote Manafzadeh in an email to Gizmodo. "This morphology of the foot has only been found in a few groups of Cretaceous theropod dinosaurs, and several biomechanical hypotheses have been emulated, linking it to an improvement in running ability."

The new document is therefore significant in that "Suskityrannus' foot is now the oldest known record of an arctometatarsal foot in a tyrannosaur", a discovery that "can potentially help us better understand evolution the ability to run in dinosaurs ". I said.

Suskityrannus hazelae may have been much smaller than T. rexbut given his presumed agility and jagged teeth, he certainly should not play it.