Apectoichnus lignummasticans Trace Fossil (IMAGE) University of Alberta Caption Photos comparing a piece of the Apectoichnus lignummasticans trace fossil (left) to gribble borings in wood collected from Willapa Bay, Washington (right). Both photos are 6 cm wide. Credit Photo credit: Scott Melnyk Usage Restrictions For use with credit. 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.