New Haven, Conn.—Triceratops and Torosaurus have long been considered the kings of the horned dinosaurs. But a new discovery traces the giants' family tree further back in time, when a newly ...

Paleontologists report that a massive horned dinosaur was roaming the American Southwest 5 million years before the well-known Triceratops ... or was that a Torosaurus? The newly named species, ...