As the names suggest, the subdivision of annelids into the Errantia and Sedentaria matches their overall lifestyles (Fig. 1). Members of the Errantia are free to move about, and crawl, swim or burrow.

Annelids are found throughout the world’s terrestrial, aquatic and marine habitats. They represent one of three major animal groups with segmentation, so understanding annelid body-plan evolution is ...

A new species of ancient sea worm with an impressively elaborate set of star-shaped chaetae has been discovered after its puzzling fossilized form was found to be animal not mineral. And just as ...