Just a little pebble

[Lone Hunter]

Yes, thank you, that was my initial thought,  all the ones I have and have seen are in mm, how large is that one?  Can they hatch with that many whorls?  Nevermind last question, apparently they hatch uncoiled, and with age they coil and reach adulthood.  So this would have to be an adult gastropod at 1 cm. ?  

Edited July 6, 2021 by Lone Hunter

[DPS Ammonite]

Can anyone show us a cross section of a coiled gastropod coiled around a hollow space like the fossil in question appears to have? All the cross sections of gastropods posted in this tread have solid center sections.

 

 

If this is a gastropod, can anyone say what the light colored (yellow) part is and what is the adjacent dark grey shell/wall (red arrows pointing to) like structure is?

Edited July 6, 2021 by DPS Ammonite

[Lone Hunter]

These are my personal reference samples.

Edited July 6, 2021 by Lone Hunter

[Thomas.Dodson]

5 hours ago, Lone Hunter said:

I would expect the whorls at tip would be much smaller, and there be some kind of evidence of sutures. Putting that aside, can anyone please just show me a picture of a gastropod with at least 11 whorls that is only 1 cm long? Then I'll shut up 

Apical angle is incredibly varied among Gastropoda. You can find some with tips that are more like clubs that barely tapered at all. You might be confused about the sutures as they are visible in your specimen. This Turritella is about 1 cm.

There are similar sized ones pictured online. Don't make the mistake of comparing whorl count among different species. Adult whorl counts vary considerably by species and 11 whorls on a 1 cm specimen is not unusual. Random examples of high spired Carboniferous gastropods from this report (http://www.paleoliste.de/bandel/bandel_2002.pdf) as examples:

 

"NIGHT (1931, Pl.2, figs.4,5) described Streptacis scalpta KNIGHT, 1931 and Streptacis crenimarginis KNIGHT, 1931 from the Pennsylvanian of Missouri which both represent high spired conical shells consisting of about 12 whorls and reaching a height of 12 mm." "54Mapesella meeki (KNIGHT, 1931) (figs. 6 - 8)Description: According to KNIGHT (1931, Pl.2, Fig.2a,b) the high spired shell with 12 whorls is about 4,5 mm high."

 

 

2 hours ago, DPS Ammonite said:

Can anyone show us a cross section of a coiled gastropod coiled around a hollow space like the fossil in question appears to have? All the cross sections of gastropods posted in this tread have solid center sections.

If this is a gastropod, can anyone say what the light colored (yellow) part is and what is the adjacent dark grey shell/wall (red arrows pointing to) like structure is?

I'm not convinced it is hollow. I suspect it could be a thick columella. Although this is supposition the outer portion of the columella might be prone to different preservation. The extensions of the columella that form the whorls usually appear different colored at any rate.

 

I have a similar specimen for comparison. I apologize for the quality, the specimen is about 4mm and is photographed through a hand lens. It can be difficult to see but note the adjacent dark outline of the columella.

 

 

 

 

[ChristineR]

Is ammonite or baculite off the table? An incomplete cross section might expose only a portion of the septa. 

 

 

 

[DPS Ammonite]

1 hour ago, Thomas.Dodson said:

I'm not convinced it is hollow. I suspect it could be a thick columella. Although this is supposition the outer portion of the columella might be prone to different preservation. The extensions of the columella that form the whorls usually appear different colored at any rate.

I think I see what you are talking about. The light colored columella surrounded by darker shell. Good job. I still don’t know how the columella from the OP could be preserved that way.

 

13 minutes ago, Christine.Rowland said:

Is ammonite or baculite off the table? An incomplete cross section might expose only a portion of the septa.

Orthocerid cephalopods existed in the Pennsylvanian and Permian deposits. Maybe it could be one. 

 

https://woostergeologists.scotblogs.wooster.edu/2013/11/03/woosters-fossils-of-the-week-very-common-orthocerid-nautiloids-from-the-siluro-devonian-of-morocco/

 

Edited July 6, 2021 by DPS Ammonite

[Top Trilo]

I still stand gastropod for a few reasons,

 

1. The difference between gastropod cross section and orthocerid cephalopod, which did cross my mind, is that the outer shell of the latter is straight or almost. While the OP's specimen is "bumpy" indicating a spiral

2. The whorls aren't perpendicular to the center line also indicating a spiral while in cephalopods the cross section is symmetrical since it doesn't spiral.

 

3. The OP's columella's edges are not flat like you would expect with a siphuncle. It kind of tapers off to the sides like you would expect in a coiled gastropod shell.

[Paleorunner]

with what you just exposed Top Trilo. I think it is enough to assume that it is a gastropod.

It's pretty clear........what else do you want? 

[JohnJ]

On 7/3/2021 at 7:10 PM, JohnJ said:

I think this one is as simple as the associated gastropods indicate...it's a gastropod cross section.  The possible local source formations have a variety snails.  This one is beautifully eroded.

 

An image search for "gastropod cross section" turned up these modern analogs.

 

Again, as evidenced by the ensuing explanations of gastropod characteristics and how they present when eroded at different angles, this is the identification with the least number of assumptions.  

 

In other words, why reach for less likely explanations when the evidence fits a more obvious one?

 

Picture the environment this piece represents.  A shell hash that contains old, eroded shells and newer shells.  The gastropod in question seems to have open whorls toward the bottom...suggesting it had already been 'decayed' and broken.  This could also explain the differences in the columella preservation.  

 

As an example, in the Texas Eocene fauna found at "Whiskey Bridge", the shells are often very fragile.  I have seen the more compacted, finer grained matrix within the whorls still retain their shape, while the powdery white shell washes away.  That presents a scenario where the apex of the gastropod may still be in hard matrix, but the columella and lower whorls flake away into oblivion.  When buried again, the preservation will vary from a pristine specimen being preserved.

[Lone Hunter]

Please read post on decending circles.

[JohnJ]

2 minutes ago, Lone Hunter said:

Please read post on decending circles.

I have and I don't even think it is close.  

[Lone Hunter]

Ok, I guess we'll agree to disagree. Appreciate everyone's time.

[JohnJ]

5 hours ago, Lone Hunter said:

Ok, I guess we'll agree to disagree. Appreciate everyone's time.

 

Until you are convinced by the evidence, I wouldn't accept an explanation based on who said it.

[Lone Hunter]

It isn't based on anything said, it's on what I see and makes sense. 

[DPS Ammonite]

If you find bigger pieces of the same rock, show them. It is hard to ID poorly preserved fossils in a small 1 inch rock. We are not even sure what age the rock is yet. 
 

Sometimes you need many pieces of the same fossil to give a good ID, especially when they are fragmentary. We all enjoyed waiving our hands trying to help.

Edited July 7, 2021 by DPS Ammonite

[Tidgy's Dad]

On 7/6/2021 at 1:11 AM, DPS Ammonite said:

Can anyone show us a cross section of a coiled gastropod coiled around a hollow space like the fossil in question appears to have? All the cross sections of gastropods posted in this tread have solid center.
 

If this is a gastropod, can anyone say what the light colored (yellow) part is and what is the adjacent dark grey shell/wall (red arrows pointing to) like structure is?

 

Yes, I can't find a picture either with a quick search. But gastropods that exhibit an umbilicus have a hollow columella. 

For instance this one would have a hollow columella through its length.

[DPS Ammonite]

Here is a freshwater snail with a hollow columella: Holospira.

 

https://en.m.wikipedia.org/wiki/Holospira

Edited July 7, 2021 by DPS Ammonite

[Lone Hunter]

From what I understand they are terrestrial and live in high desert places, other than that it's a great match. 

[DPS Ammonite]

46 minutes ago, Lone Hunter said:

From what I understand they are terrestrial and live in high desert places, other than that it's a great match. 

It was a proof of concept that a gastropod could have a hollow columella. 
 

Theoretically someone could have dumped a rock with a freshwater snail in it for you to find.

 

[doushantuo]

 

 

 

This is one of the first (and probably still one of the best) papers on spiral accretionary biomineralization:

(in other words, deducting the effects of diagenesis  and/or tectonic deformation(if any) will offer the possibiliy of arriving at biometrical

proof of molluscan affinity

 

Edited July 7, 2021 by doushantuo

[Lone Hunter]

25 minutes ago, DPS Ammonite said:

It was a proof of concept that a gastropod could have a hollow columella. 
 

Theoretically someone could have dumped a rock with a freshwater snail in it for you to find.

 

I suppose I am spoiled by seeing all the excellent examples given to OP's for comparison when trying to ID something. It's not that I disbelieve, it would just be easier to believe if I saw another one.

Edited July 7, 2021 by Lone Hunter

[doushantuo]

some of you may like:

rsif.2019.0721.pdf

 

A developmentally descriptive method for quantifying shape in gastropod shells
J. Larsson,, A. M. Westram,, S. Bengmark,, T. Lundh and R. K. Butlin

 J. R. Soc.Interface 17: 20190721.
http://dx.doi.org/10.1098/rsif.2019.0721

Edited July 7, 2021 by doushantuo

[doushantuo]

editorial note: in 2021 a paper will be published *on helicospiral gastropod morphogenesis(the first view article is presently paywalled)

edit* :in PALEOBIOLOGY

 

PLUS:

 

Edited July 7, 2021 by doushantuo

[Lone Hunter]

This is what I see in the line of balls, they are too small to capture the image but this solitary ball is the same thing. All the little balls have the same hole on top facing same direction. Just doesn't look like gastropod or even shell.

Edited July 7, 2021 by Lone Hunter

[Lone Hunter]

Can someone please tell me what the ball is?