Tiny T-Rex

A new species of predatory tyrannosauroid dinosaur that lived about 92 million years ago (Cretaceous period) has been identified from fossils found in New Mexico. The new dinosaur, named Suskityrannus hazelae, was a tiny relative of Tyrannosaurus Rex, about 9 feet (2.7 m) long and 3 feet (0.9 m) tall at the hip.

The ancient creature weighed between 20 and 41 kg, compared to a Tyrannosaurus Rex’s weight of up to 9 tons. Its diet likely consisted of the same kind as its larger meat-eating counterpart, with Suskityrannus hazelae likely hunting small animals.

An artist’s rendering of how Suskityrannus hazelae may have looked. Image credit: Andrey Atuchin.

Suskityrannus hazelae offers a glimpse into the evolution of tyrannosaurs just before they took over the planet. It also belongs to a dinosaurian fauna that just proceeds the iconic dinosaurian faunas in the late Cretaceous that include some of the most famous dinosaurs such as Triceratops, predators like Tyrannosaurus Rex, and duckbill dinosaurs like Edmontosaurus.

Two partial skeletons of Suskityrannus hazelae were found in the 1990s during expeditions to the Zuni Basin in western New Mexico.

The find links the older and smaller tyrannosauroids from North America and China with the much larger tyrannosaurids that lasted until the final extinction of non-avian dinosaurs.

The findings were published in the journal Nature Ecology & Evolution.

The Rex of Rexes

Meet Scotty, he’s the world’s biggest known Tyrannosaurus Rex, one of the most fearsome carnivores of all time. Scotty lived about 66 million years ago (Cretaceous period) in what is now Saskatchewan, Canada.

Scotty is the largest dinosaur skeleton ever found in Canada. Image credit: Amanda Kelley.

Ladies…

Scotty was 42.7 feet (13 m) long and weighed approximately 19,555 lbs (8,870 kg)!

The large, relatively complete (roughly 65%) skeleton was found in a layer of the Frenchman Formation near Eastend, Saskatchewan in 1991. Only recently, after several more years piecing together the specimen like a jigsaw puzzle, that paleontologists have been able to study the specimen.

There is a lot size variability among Tyrannosaurus. Some individuals were lankier than others and some were more robust. Scotty was clearly on the robust side. He comes out a bit heftier than other T-Rex specimens.

Scotty is also the oldest known T-Rex, meaning he would have had the most candles on its last birthday cake. Scientists can get an idea of how old a dinosaur is by cutting into their bones and studying the growth patterns. Scotty is all old growth.

Age is relative though, and T-Rexes grew fast and died young. Scotty was estimated to have been in its early 30s when he died. By Tyrannosaurus standards, he had an unusually long life. And it was a violent one. Riddled across the skeleton is scarred bone which record large injuries.

Among Scotty’s injuries are broken ribs, an infected jaw and what may be a bite from another T-Rex on its tail, battle scars from a long life.

Tyrannosaurus Rex is the largest terrestrial predator known to science.