Family tree showing the interrelationships of most known species of tyrannosaurs. Geological stages and ages (in million years) at the bottom. The new tyrannosaur Timurlengia euotica is highlighted in red. The fossilized remains of a new horse-sized dinosaur, Timurlengia euotica, reveal how Tyrannosaurus rex and its close relatives became top predators, according to a new study published in the Proceedings of the National Academy of Sciences.
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