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Mystery critter -Kiewitz Shale- SOLVED brachial valves still working on genus


LabRatKing

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LabRatKing

Finding a complete specimen is my white whale. Usually only find small fragments, these three are my most complete. Am able to use a few bits to get a “reconstruction”

 

cannot figure out what these are.

 

thanks in advance!

 

 

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551992B6-96DA-478A-BF27-1453063366B6.jpeg

C8F93751-CCC1-4654-B1C5-F349B89B0DDC.jpeg

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LabRatKing

UPDATE:

 

This is a brachial (dorsal) valve of some sort of large productine brachiopd...just managed to find a paper on them...still grinding out genus and species however, as brachiopods of this size are rare from the site.

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Thomas.Dodson

Try Echinoconchus brachial valves.

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LabRatKing
39 minutes ago, Thomas.Dodson said:

Try Echinoconchus brachial valves.

Yep, that is pretty close! Was looking at those and Pulchratia...and Just realized I may have a specimen of the "other half" that is about the right size from the same sight.

 

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8A552A4B-E34B-4F53-AE00-B4857A749B88.jpeg

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LabRatKing

So, it looks like Pulchratia sp. Not much about them from this formation. Odd that I never put 2 and 2 together after so many trips to that site over the years.

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Any reason you think Pulchratia in particular? I've tried understanding the differences between between genera in Echinoconchinae (e.g. Pulchratia, Echinaria, Echinoconchus, etc.) but found the terminology used in the descriptions to be way too complex for me to understand the differences.

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LabRatKing
31 minutes ago, connorp said:

Any reason you think Pulchratia in particular? I've tried understanding the differences between between genera in Echinoconchinae (e.g. Pulchratia, Echinaria, Echinoconchus, etc.) but found the terminology used in the descriptions to be way too complex for me to understand the differences.

In this case, decision based on timelines- only Pulchratia was reported from this Pennsylvanian period formation from what I found.

 

Echinoconchus appeared in Mississippian formations if I read it right.

 

but I am by no means a brachiopod expert. I admit normally I pretty much ignore them because they are so common here.

 

there are also some big morphological differences in the brachial valves, particularly the cardinal process. 

 

Interesting paper here that I used that discusses morphology differences:

https://www.researchgate.net/publication/250070296_Evaluating_internal_versus_external_characters_Phylogenetic_analyses_of_the_Echinoconchidae_Buxtoniinae_and_Juresaniinae_Phylum_Brachiopoda

 

(sorry for poor typing and syntax working on the mobile from the VA)

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Thomas.Dodson
51 minutes ago, LabRatKing said:

Nice paper indeed. I skimmed it and I'd agree with Pulchratia based on the lateral ridges and cardinal process shaft. I'm no brachiopod expert but the paper is very clear. Since it's reported from your formation I'd feel extra confident in the ID.

50 minutes ago, LabRatKing said:

Echinoconchus appeared in Mississippian formations if I read it right.

Echinoconchus is reported from the Pennsylvanian as well. Just figured I'd mention this.

 

@Tidgy's Dad would probably know for sure if there's any remaining doubt.

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LabRatKing
8 minutes ago, Thomas.Dodson said:

 

Echinoconchus is reported from the Pennsylvanian as well. Just figured I'd mention this.

 

Truth! Just not from this site.

 

For a real head bender try looking into Antiquatonia sp. They all look the same to me!

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Tidgy's Dad

It is too small to be Pulchratia, in my opinion, and the lateral ridges coming off the cardinal process do not bifurcate which is diagnostic of the genus. I would expect to see more clear spine bases in concentric rows on Pulchratia. 

Judging from the size, the presence of only a few notable spine bases and  the seeming occurrence of a trail on the pedicle valve , I would suggest Antiquatonia for this one. 

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LabRatKing
11 hours ago, Tidgy's Dad said:

It is too small to be Pulchratia, in my opinion, and the lateral ridges coming off the cardinal process do not bifurcate which is diagnostic of the genus. I would expect to see more clear spine bases in concentric rows on Pulchratia. 

Judging from the size, the presence of only a few notable spine bases and  the seeming occurrence of a trail on the pedicle valve , I would suggest Antiquatonia for this one. 

Excellent. I will dig into this, currently I have only found scant reports of Antiquatonia portlockianus in the Kanwaka formation's  Stull shale conspecific with the slightly more common Juresania nebrascensis and Linoproductus prattenianus. I have a few specimens and stienkern of each, Ill throw them up here a bit later on for comparison, though those are limited to pedicles and a few with intact brachials. I may have to head back there after the snow melts and get a little sifty with the freeze/thaw stuff. I can't dig there, but apparently sifting is Ok.

 

Is a bit confusing to me as these are from a well described outcrop of the Kiewitz shale, Stoner member, Stanton Formation...thus making IDs on some stuff a bit difficult. Generally, from the data available, it appears the Kiewitz and Stull are effectively the same thing...which makes little sense to me.

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LabRatKing
13 hours ago, Tidgy's Dad said:

It is too small to be Pulchratia, in my opinion, and the lateral ridges coming off the cardinal process do not bifurcate which is diagnostic of the genus. I would expect to see more clear spine bases in concentric rows on Pulchratia. 

Judging from the size, the presence of only a few notable spine bases and  the seeming occurrence of a trail on the pedicle valve , I would suggest Antiquatonia for this one. 

Is their a guide you can recommend on brachiopods?

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Tidgy's Dad
1 hour ago, LabRatKing said:

Is their a guide you can recommend on brachiopods?

I just have hundreds of papers and the Treatise, plus the Forum, of course, and a quite a few specimens for comparison. 

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LabRatKing
1 hour ago, Tidgy's Dad said:

I just have hundreds of papers and the Treatise, plus the Forum, of course, and a quite a few specimens for comparison. 

Oh boy...fun time awaits...thread to follow

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I recently found a tiny example of what I think was Pulchratia. @Tidgy's Dad concurred, at least for now.  Mine was 15mm wide and 10mm long. It was in soft material, so it came out in great shape, but is very fragile.

 

There is an example here: https://pennsylvanianatlas.org/genera/pulchratia/

 

And mine:

https://fossil.15656.com/2021/01/02/pulchratia/

 

Hope that helps. The pattern/shell is very similar with sibling taxons.

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LabRatKing
17 minutes ago, cngodles said:

I recently found a tiny example of what I think was Pulchratia. @Tidgy's Dad concurred, at least for now.  Mine was 15mm wide and 10mm long. It was in soft material, so it came out in great shape, but is very fragile.

 

There is an example here: https://pennsylvanianatlas.org/genera/pulchratia/

 

And mine:

https://fossil.15656.com/2021/01/02/pulchratia/

 

Hope that helps. The pattern/shell is very similar with sibling taxons.

I’m fairly certain that none of mine are properly identified so I’ll start a new thread in the future...

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