Triceratops

The Triceratops were a type of herbivorous dinosaurs on prehistoric Earth.

They had two large horns at the top of their heads and one small one near their nose. They weighed over a ton and could be very dangerous in a fight. They had a frill made of solid bone above their heads and ate with a beak. They, like all other dinosaurs, were wiped out when Captain Brigg's ship crashed into Earth. (DW: Earthshock)

The Third Doctor encountered a few that had been transported to the 1970s. (DW: Invasion of the Dinosaurs)

The Triceratops was also native to the planet Raxas, and along with the other Raxas dinosaurs, proved to be more than a match for a Dalek attack. (DWBIT: #7)