Tossilized Anchiornis Feather (IMAGE) Proceedings of the National Academy of Sciences Caption This is a TEM image of a fossilized Anchiornis feather showing the thick filaments composed of α-keratins dominated at the ultrastructural level. Credit Yanhong Pan 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.