White River soft shell turtle? ID

[Xiphactinus]

Finally getting around to working on a jigsaw puzzle I found in the White River Fm of Nebraska a couple of years ago. Pretty sure it’s a soft shelled turtle, but I’m not having luck finding anything like it online. The shell is eggshell thin and seems like it was leathery in life. There are a few bones included. Suggestions?

[Xiphactinus]

Adding a couple of larger images....

[Xiphactinus]

[ParkerPaleo]

Looking at a few of my books...

 

Here are the soft shell and pond turtles with some sizes.

 

Xenochelys  -  carapace ~20 cm

Apalone  -  carapace ~30 cm

Pseudograptemys  -  can't find a size but its limited to Chadronian

Chrysemys  -  carapace ~19 cm

 

Your specimen seems to be a fair bit larger than these, I suspect you have a Stylemys/Testudo and its just been deformed/compressed in a direction you aren't used to seeing.  All of the non-land turtles are all under a foot for the entire shell.  WR material is commonly compressed in one direction or another.  Post some pictures when you get more of the shell assembled and cleaned and we can get a better diagnosis.

[Xiphactinus]

Thanks! @ParkerPaleo

[caterpillar]

Why do you think it's a soft shell turtle?

[Xiphactinus]

1 hour ago, caterpillar said:

Why do you think it's a soft shell turtle?

The bones are def turtle. The shell has a distinct top and bottom with matrix in between. The shell is just a LOT thinner than I’ve ever seen. 

[jpc]

I see tortoise... Stylemys or Testudo, as PP mentioned.  There are no soft-shelled turtles in the White River.  Also soft-shelled shells are not particularly thin.  Soft-shells have a very distinctive pattern on them like this.

[LordTrilobite]

Oooh that looks like a seriously fun project.

[Xiphactinus]

6 hours ago, jpc said:

I see tortoise... Stylemys or Testudo, as PP mentioned.  There are no soft-shelled turtles in the White River.  Also soft-shelled shells are not particularly thin.  Soft-shells have a very distinctive pattern on them like this.

Any idea what would be about as thin as eggshell?  I have a lot of tortoise from there and this is nothing like that. 

[ParkerPaleo]

So a modern turtle, has bone underneath and then an eggshell of keratin on the outside protecting the bone.  Could it be preserved?

 

I don't see how the shell of a tortoise would be eggshell thin, maybe the bone is de-laminating?

 

[caterpillar]

14 hours ago, jpc said:

I see tortoise... Stylemys or Testudo, as PP mentioned.  There are no soft-shelled turtles in the White River.  Also soft-shelled shells are not particularly thin.  Soft-shells have a very distinctive pattern on them like this.

 

I agree. No soft shell turtle for me

You must clean a lot to see more

[Xiphactinus]

11 hours ago, ParkerPaleo said:

So a modern turtle, has bone underneath and then an eggshell of keratin on the outside protecting the bone.  Could it be preserved?

 

I don't see how the shell of a tortoise would be eggshell thin, maybe the bone is de-laminating?

 

Now that’s an interesting idea! More prep required....

[jpc]

6 hours ago, Xiphactinus said:

Now that’s an interesting idea! More prep required....

Thus would be a first...so I doubt it.  Knowing how many White River turtles areout there and keratin scutes have never been found.  

This looks like a large tortoise.  These really big ones form the White River are often preserved exfoliating, so that there is a lot of thin layers of shell that are really hard to isolate.  I think this is what you have.  I think I see some of this on the right end of your last photo. 

[ParkerPaleo]

That's what I meant about bone de-laminating.  Not sure its the right term.  

[jpc]

1 hour ago, ParkerPaleo said:

That's what I meant about bone de-laminating.  Not sure its the right term.  

Yeah, i thinkwe had the same idea.  

[Xiphactinus]

Appreciate the feedback, guys. I’ll post more photos when I do more prep.