A new study reveals that fossils once believed to belong to a teenage Tyrannosaurus rex may actually belong to a separate species ...

A paleontologist was trying to locate the site of a famous 1908 discovery when a rancher in Wyoming shared an important clue.

For many years, paleontologists have debated about whether there was a smaller relative of the Tyrannosaurus rex, or if those ...

Now, a research team says new evidence resolves the case. The latest clue comes from a complete skeleton — first uncovered in Montana in 2006 — that scientists say identifies the mystery reptile as ...