Debate kicked off in 1988 when a single small tyrannosaur skull discovered four decades earlier was given its own species ...

A new analysis of a fossil unearthed in 2006 provides a fresh line of evidence that a separate tyrannosaur lineage called Nanotyrannus lived alongside the famous T. rex ...

A small dinosaur skull found in Montana 40 years ago was thought to be a young T. rex. Turns out it was a smaller, faster ...

For decades, scientists argued over whether a collection of small tyrannosaur fossils from the American West were teenage ...