Naco Formation gastropod

[DPS Ammonite]

What is this cross section of a 5 cm tall gastropod from the Pennsylvanian Naco Formation of Arizona? 

The photo of whole gastropods that are similar and are found in the same formation at the Kohl’s Ranch site. Photo by Caty Sandoval. What are these?

 

This may help (I have a good guess):
 

https://www.dallaspaleo.org/resources/Documents/PGUPFT 2a Mollusca first half.pdf

Edited October 3, 2023 by DPS Ammonite

[connorp]

Strobeus would be my guess.

[cngodles]

@connorp is right on the money. Probably Strobeus paludinaeformis (Hall, 1858) due to the taller spire. The specimens appear to be only steinkerns; the shell dissolved away at some point.

 

Strobeus can be troublesome to identify down to a species-level due to it's lack of shell features and species that are divided based on small morphometric configurations—a taller spire, a sharper columnar fold, and others.

Edited October 3, 2023 by cngodles