Scientists found a prehistoric ancestor of an arrow worm among a group of fossils at two national parks in Canada. The fossils were found in what is now British Columbia, but was once an ocean. The sea worm was 10 centimeters long and had 50 spines on its head. The spines could close suddenly to capture smaller sea creatures, like shrimp. The scientists reported their discovery in the journal Current Biology in early August. They are calling the creature Capinatator praetermissus. They say it lived 500 million years ago and is very different from anything alive now. Capinatator means “grasping swimmer.”