Dinosaur Look-a-likes

Article | Updated 10 years ago

There is often confusion about what a dinosaur really is.

The frequent mention in newspapers of plesiosaurs as ‘aquatic dinosaurs’ and pterosaurs as ‘flying dinosaurs’ highlights this confusion. Although they are both prehistoric reptiles they are only distantly related to dinosaurs. Some even say crocodiles are dinosaurs but these living reptiles are only distant relations as well.

This plesiosaur, called Zarafasaura oceanis, lived in the oceans of Morocco in the Late Cretaceous

Marine reptiles
This plesiosaur, called Zarafasaura oceanis, lived in the oceans of Morocco in the Late Cretaceous. Some in this group of marine reptiles had shorter necks and larger heads. IMAGE: NOBUMICHI TAMURA

Flying reptiles

Pterosaurs were spectacular and diverse animals. This one above belonged to the azhdarchid group which included the largest of all the pterosaurs. The biggest species in this group were as tall as a giraffe when standing on the ground and had a wingspan of up to 10 metres.

Airborne pterosaur

Airborne pterosaur of the Azhdarchidae family.
IMAGE: MARK P. WITTON/SCIENCE PHOTO LIBRARY

Family relations

Pterosaurs are more closely related to dinosaurs than are plesiosaurs, but they are still not dinosaurs. The hip socket, for example, is formed by bone in pterosaurs but marked by an open hole in dinosaurs. Pterosaurs, crocodiles and dinosaurs (including birds) belong to a group called archosaurs and share several unique features in their skeleton. They all have teeth set in sockets although both pterosaurs and dinosaurs eventually evolved toothless forms.