Couple of Mazon Creek IDs needed

[Wrangellian]

This one was sold to me as the acorn worm Mazoglossus ramsdelli... it seems to match photos I see, but I'd like a second opinion, please:

 

 

 

 

This one was sold to me as Archisymplectes rhothon ('ribbon worm') but I'm less confident about this one, so, same question as above. If it's not that, what is it?

 

[RCFossils]

I agree with the acorn worm.

I do not believe that the second one is a worm.

it appears to me to be some poorly preserved plant material.

[Wrangellian]

20 minutes ago, RCFossils said:

I agree with the acorn worm.

I do not believe that the second one is a worm.

it appears to me to be some poorly preserved plant material.

OK, I guess I overpaid a bit for that one, then.  Thanks.

I guess also that I shouldn't question the first one as it came from the collection of someone who apparently knew his stuff.

[Mark Kmiecik]

6 hours ago, RCFossils said:

it appears to me to be some poorly preserved plant material.

 

I'm not sure. The preservation is not typical of flora and appears to be a continuous physical structure. This is one of those "I want to inspect it in-hand" before I make a decision.

[Wrangellian]

10 hours ago, Mark Kmiecik said:

I'm not sure. The preservation is not typical of flora and appears to be a continuous physical structure. This is one of those "I want to inspect it in-hand" before I make a decision.

Noted.

It is odd... I can usually distinguish plant and animal material in a general sense when I see it, but I am at a loss with this one. It doesn't look like the reconstruction of Archisymplectes, as the 'shafts' are too straight like they were rigid in life, but do plants look like this when they're poorly preserved? It looks more like a soft-bodied thing, but I have no idea really. (It does look more substantial than the ghostly acorn worm above.)

[Mark Kmiecik]

9 hours ago, Wrangellian said:

do plants look like this when they're poorly preserved? It looks more like a soft-bodied thing

 

Poorly preserved plants usually have more of a 3D prexence than this specimen and don't usually appear as merely a color difference in the matrix. However, note my repeated use of the word "usually".

[Wrangellian]

15 hours ago, Mark Kmiecik said:

Poorly preserved plants usually have more of a 3D prexence than this specimen and don't usually appear as merely a color difference in the matrix. However, note my repeated use of the word "usually".

Right... I do notice a bit of 3D to this one which doesn't show up in the pic, but no details that I would recognize as plant, but I guess it could be.

[Mark Kmiecik]

10 hours ago, Wrangellian said:

Right... I do notice a bit of 3D to this one which doesn't show up in the pic, but no details that I would recognize as plant, but I guess it could be.

 

By Texas rules I guess that means it's a rudist. 

[Missourian]

On 11/19/2023 at 1:00 PM, Mark Kmiecik said:

 

By Texas rules I guess that means it's a rudist. 

 

LOL. Or an inoceramid by Kansas rules

[Wrangellian]

I don't get it, did I say something nonsensical?

[Missourian]

10 hours ago, Wrangellian said:

I don't get it, did I say something nonsensical?

 

Not at all (and sorry about that... couldn't resist ).

 

I was just agreeing on the various 'laws' 'guaranteeing' that most/all rare/exceptional fossils at a site will resemble some excessively common type, in full or in part. Per the 'Kansas rules', inoceramid fragments, along with encrusting Pseudoperna congesta, resemble fish teeth, jaws, vertebrae, spines... you name it. It is really draining to find so many false-positives while scampering through the chalk badlands on a sweltering day.

 

I imagine the same could be the case with plants fragments 'posing' as various soft-bodied critters at Mazon Creek

[Mark Kmiecik]

12 hours ago, Wrangellian said:

I don't get it, did I say something nonsensical?

 

No, not at all. The running gag on this forum is that anything in Texas that can't be, or is difficult to identify defaults to being a rudist. A catch-all taxon for all things unidentified which I borrowed for temporary use in Illinois since we have not yet developed our own "rudist" ID dumpster. I have considered using coprolite for our Illinoisan un-IDs because it's also descriptive of the state of preservation.

[Wrangellian]

6 hours ago, Missourian said:

 

Not at all (and sorry about that... couldn't resist ).

 

I was just agreeing on the various 'laws' 'guaranteeing' that most/all rare/exceptional fossils at a site will resemble some excessively common type, in full or in part. Per the 'Kansas rules', inoceramid fragments, along with encrusting Pseudoperna congesta, resemble fish teeth, jaws, vertebrae, spines... you name it. It is really draining to find so many false-positives while scampering through the chalk badlands on a sweltering day.

 

I imagine the same could be the case with plants fragments 'posing' as various soft-bodied critters at Mazon Creek

 

4 hours ago, Mark Kmiecik said:

 

No, not at all. The running gag on this forum is that anything in Texas that can't be, or is difficult to identify defaults to being a rudist. A catch-all taxon for all things unidentified which I borrowed for temporary use in Illinois since we have not yet developed our own "rudist" ID dumpster. I have considered using coprolite for our Illinoisan un-IDs because it's also descriptive of the state of preservation.

 

Oh I see... Thanks for clarifying.

Up here in my local, the default ID would have to be Sphenoceramus, though one expert did take a cursory look at my sponges one time and said 'probably just some plant material'. !