The Megalosaurus (Megalosaurus bucklandi) was a type of theropod dinosaur. It was around nine feet long and three metres tall. It was found in Eurasia, specifically the parts that would later be known as England and France. It died out in the Jurassic period from environmental changes.
The last Megalosaurus was saved and kept in the Museum of the Last Ones. After the Tenth Doctor's meddling, it was accidentally released into its habitat. Unfortunately, it lived in what was later a town in England. After running amok and fighting with one of the cloned sabre-toothed tigers, the Doctor was able to freeze it in time and return it to the past. The Megalosaurus was worth 400 points in the I-Spyder Book of Earth Creatures. (PROSE: The Last Dodo)
In an alternate Earth, Megalosaurus was one of the specimens bought back from extinction by the Silurians. They were said to be one of the many predators roaming France and were presumably used by the Silurians as hunting mounts. (PROSE: Blood Heat)