Large Flat Cretaceous Bone

[TNCollector]

I have been finding associated pieces of this large bone in the same spot for several years now. Starting to come together to create a possibly diagnostic specimen. The site is in the Late Cretaceous Coon Creek formation, a near shore environment on the Eastern shore of the Western Interior Sea. The site is predominantly marine, however carbonized wood is very common and the rare bones terrestrial vertebrates have been found here before. My initial guess was something along the lines of turtle plastron, but it just doesn’t seem to quite match any I’ve seen in papers so I thought I would ask for opinions here. The bone structure is very dense and heavy. Most of it is covered by a thin layer of hardened ferrous clay that is difficult to remove.

 

Scale: black cubes are 2cm on each edge 

 

 

[TNCollector]

I believe they go together like this. 

[Rockwood]

4 hours ago, TNCollector said:

bone structure

Are you quite certain it's bone ? I see nothing that would identify it as such.

The texture looks more like plant to me.

[TNCollector]

2 hours ago, Rockwood said:

Are you quite certain it's bone ? I see nothing that would identify it as such.

The texture looks more like plant to me.

Yes this is how bone is preserved in this formation. The clay on it makes it harder to see in pictures. It sticks to it like concrete, so I am unable to clean it all off without destroying the fossil. Here is a close up cross section that might help a bit

[Shamalama]

Very cool find, even if it is in pieces and found over time. Have you tried to excavate to find more at the site?

[TNCollector]

16 minutes ago, Shamalama said:

Very cool find, even if it is in pieces and found over time. Have you tried to excavate to find more at the site?

Thanks. Yes, after finding the larger piece I did some digging and found the smaller ones. Probably still more there, I just need to let the ground soften up a bit.

[Rockwood]

Ceratopsid skull comes to mind then. The fan like texture being the indication.

[Plax]

marine turtle of some sort. The radiating lines remind me of toxochelids? but this may be a cerebral flatulation.

[Al Dente]

I also think it is a marine turtle plastron. The texture reminds me of this from the Oceans of Kansas website.

 

 

[Pemphix]

26 minutes ago, Al Dente said:

I also think it is a marine turtle plastron. The texture reminds me of this from the Oceans of Kansas website.

 

 

I agree, +1 for marine turtle...

[TNCollector]

Well I suppose that would make sense. I have found several Toxochelys vertebrae near this specimen. Interesting

[frankh8147]

I have a similar thin bone from the New Jersey Cretaceous that I have labeled as turtle plastron. It's tough to identify worn bone but I have shown this to a lot of long time Cretaceous collectors and that's the general consensus. 

[TNCollector]

3 hours ago, frankh8147 said:

I have a similar thin bone from the New Jersey Cretaceous that I have labeled as turtle plastron. It's tough to identify worn bone but I have shown this to a lot of long time Cretaceous collectors and that's the general consensus. 

Oh yeah that’s a very similar texture. I have lots of prices of marine turtle plastron, but none this big and none of my other pieces have the ribbing pattern. This must have been a very large turtle!

[frankh8147]

On 12/19/2019 at 10:30 PM, TNCollector said:

Oh yeah that’s a very similar texture. I have lots of prices of marine turtle plastron, but none this big and none of my other pieces have the ribbing pattern. This must have been a very large turtle!

 

My thought too. Keep hitting that spot and if there is a stream involved, remember to sift downstream.

 

Good luck!