minnbuckeye Posted June 27, 2022 Share Posted June 27, 2022 I stumbled onto this cute tiny gastropod from the Galena/Ordovician in Minnesota but am having difficulty with its identification. Strophostylus textiles is listed as a possiblity in Minnesota Fossils and Fossiliferous Rocks by Robert Sloan. What do you think?? Mike 1 5 Link to comment Share on other sites More sharing options...
minnbuckeye Posted June 30, 2022 Author Share Posted June 30, 2022 Just trying one more time before I let this post wither away! Are there any Ordovician experts out there????? Link to comment Share on other sites More sharing options...
ClearLake Posted July 1, 2022 Share Posted July 1, 2022 Hmmm, I replied to this last night, but I'm not sure what happened to it. Undoubtedly user error at that late hour - haha!! At any rate, my response was along the lines of based on my Ohio Ordovician experience I would call it something like Cyclonema but these internal casts are often not easy to classify and I am not familiar with Strophostylus. In looking at it a bit more this morning, the illustrations of Stropostylus in Ulrich and Scofield are more high spired than your specimen, which looks like it might match better with Cyclonema. The illustration of Strophostylus in the Treatise is not nearly so high spired (as U&S) but the diagnostic feature listed is the aperture which we can not see in yours. These two genera are closely related (more closely is some older systematics than I think the current organization is, but I am not that well versed in that) so I think you are in the ballpark and may not be able to do much better at this state of preservation. A blurb for the Equatorial Minnesota website (https://equatorialminnesota.blogspot.com/2018/11/decorah-gastropods.html) that I often find useful is: "I have some smooth bulbous snail shells I've tentatively assigned to Strophostylus, differing from the ornamented "lophospiroids" with evident ridges running around the whorls, but they could just be steinkerns of ornamented shells. More recent classifications put this genus more closely related to Cyclonema". I know your specimen is not from the Decorah, but close enough?!? 1 Link to comment Share on other sites More sharing options...
minnbuckeye Posted July 1, 2022 Author Share Posted July 1, 2022 @ClearLake, Excellent assessment! I do find an occasional Cyclonema at this site but this one is distinctly different from those. It looks like others have difficulty IDing too. Thanks for the informative response. Mike Link to comment Share on other sites More sharing options...
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