Gargantosaur

Gargantosaurs were dinosaur-like creatures that inhabited Gallifrey long before the Time Lords did. Known species included those that resembled brontosaurs, tyrannosaurs, and pterodactyls. Plutar and Sillarc traveled back in time in a TARDIS to the Gargantosaurs' era, where they narrowly avoided escaping being killed by them. (DWM: The Stolen TARDIS)