Scientists Discover Much Shorter Cousin of T. Rex

Reconstruction of the tyrannosauroid Suskityrannus hazelae from the Late Cretaceous (~92 million years ago) near the small ceratopsoid Zuniceratops and the hadrosauromorph Jeyawati in the background. (Andrey Atuchin / aatuch@yandex.ru)

(CN) – Scientists announced Monday the discovery of a closely related cousin of the Tyrannosaurus rex, a much smaller 3-foot relative that might help researchers better understand the origins of tyrannosauroids and how they evolved to become the giants of the late Cretaceous Period.

In a study released in the scientific journal Nature Ecology & Evolution, paleontologists said they discovered two skeletal remains of juvenile dinosaurs in the Zuni Basin of New Mexico dating back to about 92 million years ago. This new species, called Suskityrannus hazelae, lived 12-26 million years before Tyrannosaurus Rex walked the earth.

Paleontologists have struggled to piece together the evolutionary history of tyrannosauroids due to poor fossil preservation brought on a severe rise in sea-level and other environmental changes, but the discovery of this new species may help to fill the gap.

“This new species was phylogenetically intermediate between the grade of early-diverging, small to medium-sized tyrannosauroids that originated in the Middle Jurassic and the enormous, bone-crunching apex predator tyrannosaurids” of the late Cretaceous, researchers wrote.

The smaller cousin of the T-rex had a skull that only measured between 9.8 and 12.5 inches in length, with a long and low snout and reached about 3 feet in height. That is substantially smaller than the T-rex, which could grow to be 15 to 20 feet tall and about 40 feet in length.  Scientists say the distant cousin, although much smaller than later tyrannosauroids, shared many common features with the giants.

“The new species shows that several integral components of the tyrannosaurid-style body plan, including a cursorially adapted arctometatarsalian foot, evolved at small or medium body size,” the study states.

The paleontologists say the Zuni Basin, on the southeast border of New Mexico, has provided them a wealth of information on dinosaur species that haven’t been found anywhere else in the world. 

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