1.2" Fossil Polychaete Worm (Astreptoscolex) Pos/Neg - Illinois

This is a 1.2" fossil polychaete worm (Astreptoscolex) preserved in an ironstone nodule from the Carbondale Formation near Essex, Illinois. Both the positive (convex) and negative (concave) sides of the fossil are included.

Astreptoscolex anasillosus worms are a medium-sized polychaete that has a rounded body that tapers toward the tail. It had an eversible proboscis that carried a small set of jaws, as well as gills that are sometimes visible with nice preservation. It was likely that this worm had a tough hide or cuticle which would explain the commonly detailed preservation.