Fossil with CT Scan and Tooth Serrations (IMAGE) University of Toronto Caption Dimetrodon borealis fossil with CT scan image shows teeth with long roots (in blue) and a close-up of the tooth serrations (tiny bumps along the edges of the teeth). Credit Kirstin Brink 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.