College of Science & Engineering

Newly found dinosaur is smaller cousin of T. rex

A new relative of Tyrannosaurus rex has been identified by a team of palaeontologists including Edinburgh researchers.

The species – called Suskityrannus hazelae – dates back 92 million years to the Cretaceous period, a time when some of the largest dinosaurs ever to live walked the Earth.

It pre-dates the Tyrannosarus rex, commonly called T. rex, by about 25 million years.

The animal was around nine feet long and preyed on smaller animals, researchers say. It was considerably smaller than T. rex, which was the size of a double-decker bus, but had the same general body shape and running-adapted feet as its larger cousin.

This suggests that the tyrannosaur dinosaurs evolved their characteristic features while still small, second-tier predators.

Fossil find

An international team of scientists identified the new species by studying two fossils discovered in the late 1990s.

One of the specimens was found by Dr Sterling Nesbitt – then a 16-year-old high school student – during a dig expedition in New Mexico, USA in 1998.

Now, the fossil has been identified as a new species by a team led by Nesbitt, a palaeontologist at Virginia Tech in the US.

Edinburgh’s School of GeoSciences brought expertise on carnivorous dinosaur evolution to the project.

Suskityrannus is a key link between the enormous bone-crunching dinosaurs like T. rex and the smaller species they evolved from. The new species shows that tyrannosaurs developed many of their signature features like a muscular skull, broad mouth, and a shock-absorbing foot when they were still small, maybe as adaptations for living in the shadows.

Dr Steve BrusatteSchool of GeoSciences

Unknown dinosaur

For much of the 20 years since the fossils were uncovered, the team did not know the specimen belonged to a cousin of T. rex.

Between 1998 and 2006, the fossils were stored at the Arizona Museum of Natural History in Mesa, Arizona, USA.

After 2006, Nesbitt brought the fossils with him through various postings as a student and researcher in the American states of New York, Texas, Illinois and Virginia.

The study is published in the journal Nature Ecology & Evolution. The research was funded by the Discovery Channel.

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