An article published in the journal “Current Biology” describes a research on Kootenayscolex barbarensis, a bristle worm (class Polychaeta) that lived about 508 million years ago in the site of today’s Marble Canyon, in the Burgess Shale, Canada. Karma Nanglu and her supervisor Jean-Bernard Caron of the University of Toronto and the Royal Museum of Ontario studied this very ancient annelid. It’s a sea animal although it’s related to the current earthworms. The most important thing is that its discovery provides new information on the origin of the annelids’ head.