Iguanodon

The Iguanodon was a species of Dinosaur, who existed around 177 million years before the 20th century.

It was about nine metres long and five metres high, and a herbivore. It had two short, sharp spikes on the ends of its thumbs, which it used to defend itself from predators. The Fourth Doctor showed an Iguanodon to a travelling companion and told them that it was one of the first Dinosaurs that Humanity had found out about, around 150 years before the companion's time. (PROSE: The Doctor Who Dinosaur Book)

The Museum of the Last Ones sold masks in the shape of Iguanodon heads in its gift shop. Frank wore one of these masks when selling Mervin the Missing Link to Professor Dougal Dunnock. (PROSE: The Last Dodo)