Eunicites diopatroides
Middle Cretaceous (Cenomanian)
Hajoula, Lebanon

Very fine 72mm on 109mm slab

Worm.  Polychaete.

We think of all worms belonging to the same group but they have been quite diverse across geologic time representing more than one phylum, reflecting separate ancestries.  Polychaete worms (aka bristle worms) belong to the Class Polychaeta and date back to the Early Cambrian.  Some modern forms like earthworms and leeches may be descendants of the group.

The most common polychaete fossil remains are their jaws which are called scolecodonts.  Body fossils are known in some deposits but only where soft-bodied organisms can be preserved such as Mazon Creek and the Hajoula site.