Poterioceras curtum is a Pennsylvanian cephalopod first described by Meek & Worthen in 1860.

I originally misidentified these as Ctenobactrites isogramma.

Poterioceras curtum specimen with the shell attached to the steinkern.
CG-0436 – Poterioceras curtum specimen with the shell attached to the steinkern. The attachment and shell are fragile, thus further removal was avoided.
Poterioceras curtum fragments.
CG-0369—Poterioceras curtum fragments. These are shells from at least two different creatures.
Poterioceras curtus shell
CG-0455—Poterioceras curtum shell. All four pieces were connected together before retrieval. Note the larger spacing towards the bottom, and the curved-eyed feature on the bottom left of the bottom right piece, perhaps a shell repair during growth. Scale bar = 1 cm.

This is not the first report of this species in Western Pennsylvania. A report from the Annals of the Carnegie Museum in 1947 features specimens from the Brush Creek limestone in Western Pennsylvania at Witmer and at the Sewickley bridge. They are both deposited in the Carnegie Museum as CM 25786 and CM 25787.