Osteoderm? Shell? Skull?

[garyc]

So from the title I obviously have no idea what this is. Usually when I pick up something like this I just call it turtle. This does not seem like turtle …. Soft shell or any other that I’ve found. I’m wondering if it could be an osteoderm, but what?

[Thomas.Dodson]

The surface reminds me of an epiphyseal plate.

[CDiggs]

8 hours ago, Thomas.Dodson said:

The surface reminds me of an epiphyseal plate.

Agreed, an un-fused one one from a juvenile. I'd guess from a vert.

[fifbrindacier]

What kind of animal could have a cartilage been preserved by fossilization ? Because it means that it countained a lot of calcium like it is the case with sharks.

A turtle ?

Edited October 20, 2023 by fifbrindacier

[Fin Lover]

I have found cetacean verts with these.

[fossilus]

1 hour ago, fifbrindacier said:

What kind of animal could have a cartilage been preserved by fossilization ? Because it means that it countained a lot of calcium like it is the case with sharks.

A turtle ?

 

If I understand correctly,I don't think that these have much to do with cartilage or calcium. They are really just the mechanism that, for mammals at least, that allow a bone to grow larger - they allow a small gap where new bone can grow. The gap disappears when the animal is mature. I don't know that you see these in reptiles because they grow differently.

[fifbrindacier]

40 minutes ago, fossilus said:

 

If I understand correctly,I don't think that these have much to do with cartilage or calcium. They are really just the mechanism that, for mammals at least, that allow a bone to grow larger - they allow a small gap where new bone can grow. The gap disappears when the animal is mature. I don't know that you see these in reptiles because they grow differently.

If it's an epiphysal plate, it must be cartilage and shark's ones fossilize better than mammal's or reptile's or so i think.

As it is said by @CDiggsit must come from a juvenile.

[fossilus]

24 minutes ago, fifbrindacier said:

If it's an epiphysal plate, it must be cartilage and shark's ones fossilize better than mammal's or reptile's or so i think.

As it is said by @CDiggsit must come from a juvenile.

 

You probably come at this from a marine point of view. The South brazos is generally non marine and I don't know of any shark material  being found there,  and I've hunted the river for 30+ years.

Edited October 20, 2023 by fossilus
Accuracy

[fifbrindacier]

No i'm not at all saying there is shark there.

I'm only soeaking about cartilage and that the only ones i know come from sharks.

That's the first i see from anorhrr animal.

[fossilus]

25 minutes ago, fifbrindacier said:

No i'm not at all saying there is shark there.

I'm only soeaking about cartilage and that the only ones i know come from sharks.

That's the first i see from anorhrr animal.

 

 

I see that you are correct about the cartilage. 

But I think that this is the bone plate rather than the epiphyseal cartilage between the bones. I've often seen bones that have broken along this boundary, like @CDiggs said, it would come from an immature animal.

[sjaak]

This is an unused bone plate (epifysial plate) of a vertebra. When the animal grows older it fuses with the vertebra. The structure looks a bite like a marine mammal. 

Edited October 20, 2023 by sjaak

[garyc]

Thanks for all the responses. I it makes sense that this is an epiphyseal plate. I have not seen the plate separated from the bone, but I have seen the bones that are missing the plate and they have the same sort of pattern. Like @fossilus said it would be highly unlikely for this to be from a shark or marine mammal. I also doubt that this is cartilage. It’s hard to tell from the picture of the side view, but that is cancellous bone structure.