Cartilaginous Fishes (IMAGE) University of Zurich Caption Cartilaginous fishes were very diverse during the Permian period. However, after severe losses among cartilaginous fishes during the Middle Permian extinction, bony fishes experienced a massive diversification in the subsequent Trias period. Credit Image: UZH Usage Restrictions None License Licensed 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.