Before the mighty Tyrannosaurus rex and its relatives ruled the Mesozoic world's last act, Earth's top predators were the Carcharodontosaurids. These huge carnivores, named for their distinctive shark ...

In the Late Cretaceous, the region of South America that would one day become modern Argentina was a dramatic land indeed.

Altogether, the pieces reveal a slender tyrannosaur that roamed Cretaceous Mongolia about 86 million years ago and was about ...