The Diplodocus was a type of herbivorous dinosaur. (AUDIO: The Creeping Death) The Diplodocus was worth 600 points in the I-Spyder Book of Earth Creatures if it was spotted.The last Diplodocus was an exhibit in the Museum of the Last Ones. When the Tenth Doctor and Martha Jones visited, Martha remarked about how large it was. (PROSE: The Last Dodo)
In an alternate timeline Diplodocus was one of the many specimens bought back from extinction by the Silurians. It was said [who?] that huge herds roamed across France. (PROSE: Blood Heat)