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Tidgy's Dad

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Hello, my friends, tis I once more with queries regarding odds and ends found in matrix from Southgate Hill road cutting, St. Leon, Indiana. Late Ordovician from the Upper Arnheim, Waynesville, Liberty and Lower Whitewater formations. 

Is this first one a bit of free cheek with a spine base? The piece is 1.5 mm wide and the big brachiopod bottom left is the edge of a Strophomena planumbona. 

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I am pretty certain that this next one is a hypostome. It looks like some of the Isotelus ones I have seen but is very small. 2.5 mm. A small Isotelus? Another trilo? Or the Millennium Falcon? 

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I think this is another hypostome. But of what? It's actually in the same rock as the one above but is a little bigger at 3 mm from tip to tip.

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Closer look :

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This one's enormous by comparison, 1.9 cm from curve to tip. But I'm not sure it is a hypostome. It sort of looks like part of the internal structure of a brachiopod or bivalve but I can't for the life of me think what. Especially at this size.

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Close up :

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Are these ostracods? Quite a lot of them in this rock, 0.5 to about 1 mm wide :

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@connorp @erose @Kane @piranha @ClearLake

And all comments welcome from anyone else. 

Thank you all very much for any assistance.   

 

 

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Life's Good!

Tortoise Friend.

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On FB at the Dry Dredgers members page Steve Brown recently had a presentation on Cincinnatian trilobites and their associated hypostomes. If you are not a member of the Dry Dredgers you should be. They are the oldest paleo club in the country and super nice folks.

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Adam, I do believe those are ostracods in your last picture.  Attached below is a partial plate from Pojeta's 1984 USGS Professional Paper 1066-J on Ordovician Ostracods from Kentucky and nearby.  The ostracod in the middle of your picture could be like the Kenodontochilina shown in Figure 3 below.  The straight hinge line would be partially buried in the sediment on the left side of your specimen.  I think I see the furrow and bump next to it on your specimen but you should be able to tell better looking at it in person than I can from the photo.

 

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I also think all your others are hypostomes but they do not look like Isotelus ones I have found and seen figured.  It would be great to get a hold of the presentation @erose mentioned.  I don't usually "do" FB, but a quick check on it did not lead me to the post he mentioned, but I am a totally novice so take that for what its worth (very little).  Those are some neat looking ones and I hope to see some ID's on them.

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5 hours ago, ClearLake said:

Adam, I do believe those are ostracods in your last picture.  Attached below is a partial plate from Pojeta's 1984 USGS Professional Paper 1066-J on Ordovician Ostracods from Kentucky and nearby.  The ostracod in the middle of your picture could be like the Kenodontochilina shown in Figure 3 below.  The straight hinge line would be partially buried in the sediment on the left side of your specimen.  I think I see the furrow and bump next to it on your specimen but you should be able to tell better looking at it in person than I can from the photo.

 

I also think all your others are hypostomes but they do not look like Isotelus ones I have found and seen figured.  It would be great to get a hold of the presentation @erose mentioned.  I don't usually "do" FB, but a quick check on it did not lead me to the post he mentioned, but I am a totally novice so take that for what its worth (very little).  Those are some neat looking ones and I hope to see some ID's on them.

Thanks very much for the ostracod suggestion I'll see if I can get a better angle of one of them. 

I don't do FB either and would really rather not start now, to be honest. 

Grateful for the idea though @erose and I might have to take the plunge if the information is not forthcoming elsewhere.   

Life's Good!

Tortoise Friend.

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9 hours ago, Tidgy's Dad said:

0d.thumb.jpg.d1bf27a1ace0942b2114f48f1fd766d6.jpg

 

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I'm on the fence about the first one, tempted to say it is a Flexicalymene hypostome... but the spinose projections don't quite fit (unless it is a broken off bit). There seems to be a border furrow here, which is why I haven't given up the idea it may indeed be a hypostome. 

 

The second one looks more typical of an Isotelus hypostome with the wide notch at the posterior margin characteristic of these, and what appear to be terrace lines on the median body. Of course, the "shoulders" are long gone.  What bothers me about this one is that I'd expect to see some terracing on the fork. 

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...How to Philosophize with a Hammer

 

 

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4 hours ago, Tidgy's Dad said:

I don't do FB either and would really rather not start now, to be honest.

:thumbsu:

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image.png.7e535951563f886f7d378d92243c6f61.png

 

Evitt, W.R., Whittington, H.B. 1953
The Exoskeleton of Flexicalymene (Trilobita).
Journal of Paleontology, 27(1):49-55

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1 hour ago, piranha said:


The Exoskeleton of Flexicalymene (Trilobita).

Perfect match.

Thank you, Scott:)

How about the Millennium Falcon? 

Another of the same? 

Life's Good!

Tortoise Friend.

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Thanks, everyone, this has all been very helpful. :i_am_so_happy:

Life's Good!

Tortoise Friend.

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