Panser Shark (IMAGE) Arizona State University Caption A panser shark (predatory fish greater than 30 feet long) is a consequence of the Earth's oxygenation event of 400 million years ago. Credit Staffan Waerndt/ Swedish Museum of Natural History 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.