Mazon Creek Polychaete Worm Fossil with Preserved Jaws

Name: Esconites zelus

Phylum: Annelida; Class Polychaeta; Order Euicida, Family Eunicidae

Geological Time: Pennsylvanian (~300 m.y.a.)

Size (25.4mm=1 inch): 41 mm long on a 47 mm by 62 mm nodule

Fossil Site: Mazon Creek, Pit 11, Francis Creek shale, Braidwood, Illinois

Polychaete Worm fossilThe Polychaeta (Bristleworms) have a diverse representation among Mazon Creek specimens. The segmented bodies of the Polychaeta have paired lobes called parapodia which have a function in locomotion or respiration. The parapodia bear numerousPolychaete Worm with Preserved Jaws bristles which are the source of the name of the class (Polychaeta means many bristles). This one is sure to have been a predatory species, as are many modern-day bristleworms, due to the fact that it possesses a formidable pair of jaws which were mounted in an evertible proboscis. Note the jaws readily displayed in the close up photo. They are often the best-preserved features of the animal. The genus derives its name from ESCONI, an acronym for Earth Science Club Of Northern Illinois.

click fossil pictures to enlarge

Fossil Museum Navigation:
Geological Time Paleobiology Geological History Tree of Life
Fossil Sites Fossils Evolution Fossil Record Museum Fossils