In 1887, the first bones of a Triceratops were discovered in Denver and were sent to Othniel Charles Marsh. At first, Marsh believed it was a bison. It wasn't until more Triceratops bones were found in 1888 that Marsh gave the beast the name Triceratops. read more
There is evidence that Tyrannosaurus did have aggressive head-on encounters with Triceratops, based on partially healed tyrannosaur tooth marks on a Triceratops brow horn and squamosal; the bitten horn is also broken, with new bone growth after the break. read more