My colleagues and I discovered a new species of extinct crocodile from a fossil found in the same rocks used to carve the Great Sphinx of Giza.

Today, there are only two species of the long-snouted gavial crocodile, both of which are endangered: Gavialis gangeticus and Tomistoma schlegelii. They are found only in freshwater environments on the Indian subcontinent and Southeast Asia.

However, the fossil record of gavials goes back 80 million years, to the time of the dinosaurs. It shows that they were once diverse, with more than 40 species known, and lived all over the globe. So how did a group of crocodiles that today cannot tolerate saltwater once live all over the world? Our discovery may help to solve this puzzle.

Although the distribution of the continents differed from today, most were already separated by oceans. My colleagues and I have been trying to understand how gavials achieved this cosmopolitan distribution, while also seeking to unlock what led to their current predicament.

Studying the anatomy of the skeletons of living and fossil gavials has given us a better understanding of the group’s evolution in recent years. CT scans have enabled us to look inside their skulls, giving us a window into their brains and sensory systems.

This has revealed new anatomical information that helps differentiate species, and has allowed us to infer aspects........

© The Conversation