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 planet Skaro was also home to creatures that resembled dinosaurs, specifically the Triceratops but with only one horn. Normally peaceful herbivores, they would attack Daleks on sight. The Third Doctor and Finney used a herd of these to destroy a group of Daleks that had taken them to Skaro. (TVA: The Planet of the Daleks)

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)