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ID for dark, flat fragments in Upper Ordovician deposits


David Fankhauser

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David Fankhauser

These are not the largest specimens of this broad flat smooth dark fragment, but you can see some fragments in this sample collected from 9 mile creek just east of Cincinnati.

 

Yes, that is a gorgeous pygidium, presumably from Flexicalimenes?

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David Fankhauser

Sorry, I am a rank newbie to this forum, and was I’m successful at getting the images posted. I subsequently resubmitted and the pictures were posted. Here are the two images which should’ve been with this initial postI’m successful at getting the images posted. I subsequently resubmitted and the pictures were posted. Here are the two images which should’ve been with this initial post.

 

C337D2D9-E347-495D-876C-FD91F51690B8.jpeg

8B54C288-930C-42C1-A981-9574EDED3A13.jpeg

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If you're referring to the smooth bit to the upper left of the larger Flexicalymene pygidium, I would guess those would be Isotelus fragments. 

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David Fankhauser

 I am asking about the smooth, dark, flat pieces in the upper left quadrant of this image. I have seen much larger pieces, but they have few features other than their smooth, dark flatness. Thank you for your hypothesis.

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6 minutes ago, Kane said:

larger Flexicalymene pygidium,

Okay. Scratch the leptaena idea. :shakehead:

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According to the faunal list of these formations, I reiterate Isotelus sp. fragment as a likely candidate. These are fairly typical of the turbid Ordovician deposits spanning Cincinnati to the Ordovician band in Ontario. 

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Fossildude19

+1 for Isotelus bits. 

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David Fankhauser

Thank you very much. From the size of these fragments, I would guess that Isotelus is one of the larger trilobites.

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1 minute ago, David Fankhauser said:

Thank you very much. From the size of these fragments, I would guess that Isotelus is one of the larger trilobites.

These asaphids could attain impressive size. In fact, the largest complete trilobite ever found was Isotelus rex in Manitoba at 720mm. :default_faint:

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David Fankhauser

Asaphid is a new term for me, thanks!

(https://en.m.wikipedia.org/wiki/Asaphida)

For many years I have found remnants of the lace collar trilobite in strata of Upper Ordovician deposits in south western Ohio. 

I have  Learned that this species is the index fossil for the Kope formation. Right?

 

What is new and exciting to me is that there appear to be at least three different species of trilobites found in these Kope deposits, cryptolithus, Flexicalimenes and Isotelus.

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2 hours ago, David Fankhauser said:

Asaphid is a new term for me, thanks!

(https://en.m.wikipedia.org/wiki/Asaphida)

For many years I have found remnants of the lace collar trilobite in strata of Upper Ordovician deposits in south western Ohio. 

I have  Learned that this species is the index fossil for the Kope formation. Right?

 

What is new and exciting to me is that there appear to be at least three different species of trilobites found in these Kope deposits, cryptolithus, Flexicalimenes and Isotelus.

There are many more species present although much less common than the three you mentioned.

 

Check out the Dry Dredgers web site http://drydredgers.org  for a more complete list of Cincinnatian trilobites.

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