Tentaculites? Cephalopod?

[SilurianSalamander]

Found at work. Ordovician to Devonian. It tapers so it’s not a crinoid stem

 

Edited September 9, 2022 by SilurianSalamander
More info

[Kane]

Looks crinoidal to me.

[Fossildude19]

Cephalopod is the most likely answer here, I think.

[The-Good-Earth]

Ya I think the segments with taper is the key. I vote Cephalopod as well

[erose]

There are other echinoderms with tapering stems. Look at rhombiferans.

[Mochaccino]

Is the cross-section visible? As @erose mentioned, rhombiferan cystoids tend to have tapering stems, and some crinoids do as well. Also a more specific locality info might help.

[SilurianSalamander]

No cross-section is visible. Ordovician-Devonian rock most likely, probably Silurian. Found alongside agatized corals and stromatoporids with the occasional brachiopod or crinoid bit. Waukesha Wisconsin, fox river park

[Mochaccino]

On 9/9/2022 at 8:09 PM, SilurianSalamander said:

No cross-section is visible. Ordovician-Devonian rock most likely, probably Silurian. Found alongside agatized corals and stromatoporids with the occasional brachiopod or crinoid bit. Waukesha Wisconsin, fox river park

The two things your specimen most reminds me of are 1. The stems of rhombiferan cystoids, such as Ordovician Glyptocystites:

 

http://paleoportal.org/index.php?globalnav=fossil_gallery&sectionnav=detail&submission_id=1492&taxon_id=60&last_section=taxon&printer_friendly=1

and 2. certain straight-shelled nautiloids, such as Dawsonoceras or Spyroceras:

 

https://louisvillefossils.blogspot.com/2016/12/silurian-dawsonoceras-annulatum.html?m=1

https://louisvillefossils.blogspot.com/2012/01/spyroceras-cephalopod.html?m=1

 

Of which if it's Silurian-aged, Dawsonoceras may be a better match.

 

Unfortunately I'm not knowledgeable enough to pin down the ID, but visually they are some possible matches. If it's Wisconsin I might lean towards cephalopod, since I'm not aware of any cystoids from that locality but cephalopods like Dawsonoceras apparently do occur there: https://cdm15963.contentdm.oclc.org/digital/collection/paleo/id/3331

 

Edited September 13, 2022 by Mochaccino

[aek]

@SilurianSalamander It is the the lateral thoracic view of a Silurian Gravicalymene celebra. It's missing the cephalon and the rest of it has broken off and weathered away. The arrow on the left is where the cephalon broke off and the top arrow shows where the median axial lobes begin.

[SilurianSalamander]

19 hours ago, aek said:

@SilurianSalamander It is the the lateral thoracic view of a Silurian Gravicalymene celebra. It's missing the cephalon and the rest of it has broken off and weathered away. The arrow on the left is where the cephalon broke off and the top arrow shows where the median axial lobes begin.

 

 

100% agree. This makes the most sense with the texture outside of the main ridge. Thanks so much!

[Tales From the Shale]

That is a cool trilobite fragment. I really forgot how much you can find in Wisconsin by looking at gravel alone.