Chimaeras (image) Schmidt Ocean Institute Share Print E-Mail Caption Chimaeras are cartilaginous fish, largely confined to deep water. Their closest living relatives are sharks, though their last common ancestor with sharks lived nearly 400 million years ago. Credit Schmidt Ocean Institute Usage Restrictions Onscreen/print credit. Share Print E-Mail 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.