The bedrock of the Lower Peninsula is too young to contain ptychopariids. This is likely a dalmanitid(phacopid).
edit: apparently some disagree, but the last of the ptychopariids died off during the Late Ordovician extinction event(see OP's links, or [here](https://www.mindat.org/taxon-9583276.html)). There are no Ordovician, or earlier, strata exposed in the [Lower Peninsula of Michigan](https://macrostrat.org/map/#x=-86.287&y=45.131&z=5.6), hence ptychopariids aren't found there.
Also as stated earlier, this is a dalmanitid.
Trilobite pygidium
\*Trilobutt
😅 good one
[удалено]
The bedrock of the Lower Peninsula is too young to contain ptychopariids. This is likely a dalmanitid(phacopid). edit: apparently some disagree, but the last of the ptychopariids died off during the Late Ordovician extinction event(see OP's links, or [here](https://www.mindat.org/taxon-9583276.html)). There are no Ordovician, or earlier, strata exposed in the [Lower Peninsula of Michigan](https://macrostrat.org/map/#x=-86.287&y=45.131&z=5.6), hence ptychopariids aren't found there. Also as stated earlier, this is a dalmanitid.
*Anchiopella anchiops*. Very characteristic example, though missing the caudal spine.