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Identification Help from Mazon Creek, Pit 11 (Arthropod appendage?)


Thomas.Dodson

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Thomas.Dodson

Hello all,

I have been a long time lurker of the forum (simply reading has been helpful enough these years) but have finally decided to request identification help on some fossils. I spent the summer conducting research in Illinois and spent my spare time collecting fossils. I was fortunate enough to collect Mazon Creek fossils about 14 years ago on a trip so I was thrilled to finally return to the area and collect at the Mazonia Braidwood Fish and Wildlife Unit. I have Key to Identify Pennsylvanian Fossil Animals of The Mazon Creek Area as well as Jack Wittry's The Mazon Creek Fossil Flora and these have been very helpful in identifying specimens but this one has thrown me a bit.

 

As for the fossil, it resembles an arthropod appendage (like a Eurypterid walking leg) but I might be blinded by my wishing it to be that. :rolleyes: I appreciate any help and insight from people more experienced with Mazon Creek.

 

I will likely post more unidentified material from Illinois and Missouri soon. Thanks for your time.

 

-Tom

 

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I don’t know what this is, looks really different.  I am thinking flora too, but with it coming from Pit 11 you only hope that it is of animal origin. I will tag @RCFossils on this.

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Here is a pic I took on Saturday at Dave’s Down to Earth Rock Shop of a Mazon Creek Eurypterid.

 

927B66A1-112B-418F-B4B8-8F69D2A840B8.thumb.jpeg.d1d26119b2ec74cc5cac1ea99d61cd47.jpeg

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I think JPC might have nailed it. 

It was the first thing I thought of. 

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Thomas.Dodson

A shrimp tail seems likely now that you point it out. The split structures at the end (harder to see the detail of it in the photo, I need a better camera) splits as the telson/uropods would in most shrimp. I like the position of the tail. Thanks for your help everyone!

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What is ND ? Wiki tells me that Jamestown is in Virginia.

 

Coco

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6 hours ago, Coco said:

What is ND ? Wiki tells me that Jamestown is in Virginia.

 

Coco

Coco, 

ND is the abbreviation for the state of North Dakota.  :) 

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Thanks a lot Tim, I try to registred the states abbreviations, but some of them give me more problems... For me, asking is learning (or studying) ;)

 

Coco

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2 hours ago, Coco said:

Thanks a lot Tim, I try to registred the states abbreviations, but some of them give me more problems... For me, asking is learning (or studying) ;)

 

Coco

There is a Jamestown in ND, too.  But don't worry, coco.  Most of us americans have no idea about the subdivisions of France.  

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@Thomas.Dodson, I used to live in Jamestown, ND in 2018! I found few fossils at Pipestem reservoir.

 

Sorry for being off topic. As for that Mazon fossil - sorry, I know almost nothing about them. Good luck and I hope others on here will have positive identification for you.

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On 10/23/2020 at 9:03 PM, Thomas.Dodson said:

Hello all,

I have been a long time lurker of the forum (simply reading has been helpful enough these years) but have finally decided to request identification help on some fossils. I spent the summer conducting research in Illinois and spent my spare time collecting fossils. I was fortunate enough to collect Mazon Creek fossils about 14 years ago on a trip so I was thrilled to finally return to the area and collect at the Mazonia Braidwood Fish and Wildlife Unit. I have Key to Identify Pennsylvanian Fossil Animals of The Mazon Creek Area as well as Jack Wittry's The Mazon Creek Fossil Flora and these have been very helpful in identifying specimens but this one has thrown me a bit.

As for the fossil, it resembles an arthropod appendage (like a Eurypterid walking leg) but I might be blinded by my wishing it to be that. :rolleyes: I appreciate any help and insight from people more experienced with Mazon Creek.

I will likely post more unidentified material from Illinois and Missouri soon. Thanks for your time.

 

-Tom

 

IMG_6178.thumb.JPG.3b8efdfa6f8ad85cb843e7b2cbc269ad.JPGIMG_6179.thumb.JPG.6e5189cb2a1adf187dcb98cd8962c8e8.JPG

I am fairly certain that this is Calamites.

you can see the circular nodes at the joints.

 

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Looks plant-like.  Calamites stem seems right.  Shrimp tails wouldn't be that long and slim.  Also, they wouldn't have a segment beyond the telson.

 

Can you get a closer picture with some magnification?

 

Cheers,

Rich

 

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This is a very unusual form, which is obvious when there is no agreement on even what kingdom it belongs in. It's affinities may never be known, but I will throw out my opinion and see what sticks. What I believe is, this is a fertile structure of a rare plant. I have only seen a couple of small fragmentary sterile leaves that likely belong to this taxon at Mazon Creek. The seeds to this plant have only been found detached but in close association to the foliage at locations in England. The shape of the seed is very unique, much like a three pointed shield with a pair of long horns, a keel down the middle, and an attachment point located between the horns. To me they look very similar to the four segments on this specimen, and also are of the correct size. I believe what this is, is the female fertile structure with attached ovules (seeds) of Eremopteris zamiodes.

 

Hope this is interesting, if not helpful, 

Jack  

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Thomas.Dodson

Very interesting information coming out. Originally I thought this was flora and set it aside with other flora but after I examined it closer it felt like it could be something else. Now I'm leaning back towards flora. A few thoughts:

 

It seems rather different than typical Calamites forms because I see only a single circular joint at the internodes. That said, the circular impressions do bare a resemblance to internode tubercles or foliage scars. There isn't any striae to note despite the decent preservation and the horns aren't characteristic of Calamites that I'm aware of.

 

Rich; what made me suspect this might be a shrimp tail like others mentioned is in fact three distinct points that resemble a thin telson and uropods at the end after the last segmented piece. I circled it in the included picture. The arrow would be the last abdominal segment before it. It can be difficult to tell because they overlap somewhat but there are at least three projections. That said, the lack of taper and the overall length is suspicious. The spines also seem exaggerated.

 

Jack's opinion is interesting and addresses features of the fossil that are unique and, to a certain extent, difficult to see with the current pictures. There is a distinct keel (one of the features that originally made me think it might be animal), notable horns, the attachment point, and the three extensions attached to the last segment. Because it accounts for most of the unique characteristics this seems like my favorite ID right now but he's correct that it may never be known.

 

This is turning out to be a much more fun fossil than I thought! I'll break out the macro lens on the better camera and try to get some more detailed pictures of the three points. Thanks for the effort everyone!

 

 

@DarbiThat's interesting about Pipestem. Were there any in-situ fossils? In North Dakota I usually have to get to the Sheyenne River valley for the closest bedrock formations and prefer to get out to Bismarck and south.

 

 

IMG_6210.JPG

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1 hour ago, fiddlehead said:

This is a very unusual form, which is obvious when there is no agreement on even what kingdom it belongs in. It's affinities may never be known, but I will throw out my opinion and see what sticks. What I believe is, this is a fertile structure of a rare plant. I have only seen a couple of small fragmentary sterile leaves that likely belong to this taxon at Mazon Creek. The seeds to this plant have only been found detached but in close association to the foliage at locations in England. The shape of the seed is very unique, much like a three pointed shield with a pair of long horns, a keel down the middle, and an attachment point located between the horns. To me they look very similar to the four segments on this specimen, and also are of the correct size. I believe what this is, is the female fertile structure with attached ovules (seeds) of Eremopteris zamiodes.

 

Hope this is interesting, if not helpful, 

Jack  

This would be quite interesting.

I am still leaning more towards some form of Annularia/Asterophyllites.

There is a structure laying on top of one of the nodes which looks very much like an annularia whorl.

Please check out the image and let me know what you think.

i have quite a few specimens in my collection that appear to have similar structures.

Based on your new book, I would call my specimen Annularia annulariaefolius.

9D45467D-A2DB-4D87-BB6C-3DDA7C5C0D13.jpeg

F28698DF-3B93-4277-86B9-D48722BA304C.jpeg

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Here are a few more images of one of my specimens for comparison.

 

F7A18693-4426-4044-9BA6-7BADC85273EA.jpeg

208D86C4-A356-4576-A998-707C1E9EB052.jpeg

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Thomas.Dodson

I have tried to take more detailed pictures while toying around with different light to contrast details. I'm a little underwhelmed by the result but hope this highlights the carina, nodes, and points better. It's very difficult to highlight the middle extension in a way that shows all three points the way the eye does.

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As an invertebrate guy, I see annularia as others have posted. Still a specimen I am jealous of, but I see none of the arthropod anatomy I would.

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On 10/25/2020 at 9:38 PM, Thomas.Dodson said:

Were there any in-situ fossils?

 

Not that I know of. I don't think there are any in-situ fossils around there. I found a couple petrified woods and a brachiopod hash plate along the shoreline when the water was down, but these fossils were found among the glacial erratics, so probably transported from hundreds of kilometers several thousands of years ago. I have looked for fossils at Pierre Shale outcrops around Jamestown Reservoir and its island with no luck.

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Thomas.Dodson
4 minutes ago, Darbi said:

Not that I know of. I don't think there are any in-situ fossils around there. I found a couple petrified woods and a brachiopod hash plate along the shoreline when the water was down, but these fossils were found among the glacial erratics, so probably transported from hundreds of kilometers several thousands of years ago. I have looked for fossils at Pierre Shale outcrops around Jamestown Reservoir and its island with no luck.

That's pretty much my experience with the few Pierre Shale outcrops here. I have had some success with the Pierre Shale in Valley City, though.

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