Poposaurus (IMAGE) University of York Caption Poposaurus, from a group of extinct relatives of the crocodile known as Poposauroidea. This crocodilian was around four meters long and lived alongside dinosaurs from 237 to 201.3 million years ago. Credit Jagged Fang designs Usage Restrictions For use when covering this research License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.