Dimorphodon (name meaning "Two-form Tooth") is genus of pterosaur that originated during the Early Jurassic period in what is now Europe. Hence its name, this pterosaur was named due to its two distinct types of teeth in its jaws.
In the Series 4 episode "New Arrivals", a flock of Dimorphodon somehow came through the portal from Early Jurassic Europe, 175 million years ago. They reside in the Aviary Enclosure with other pterosaurs that reside there.