Catalog Number: CG-0040

This trilobite tail, also known as a pygidium was embedded in Brush Creek Limestone. By the Carboniferous, trilobites were on the decline, and evolution was making them smaller and smaller. Only the order Proetida survived into the Carboniferous, and later died out at the end of the Permian.

It would appear the two species to represent the Brush Creek limestone are Ameura missouriensis (Shumard) and Ditomopyge scitula (Meek & Worthen). This could be a tail from either one. In the Ames Limestone, Ditomopyge decurtata (Gheyselinck) can be found.

Pennsylvanian Trilobite Diagram

Below is a diagram of a typical Pennsylvanian trilobite. As you can see in green, the pygidium, or tail, contains the pleural and axial Lobe. These are both visible in the above specimen.

Pennsylvanian Trilobite Diagram.
Redrawn from Figure 64 from Record of Rock: A Handbook of the Invertebrate Fossils of Nebraska

More about Carboniferous Trilobites Online