Help Identify

[LynWil]

Can someone help

me identify these? They have very unusual patterns on them. Thought it would be easy to identify, but I can not seem to find them. Maybe some type of osteoderm? I have included 3 pictures of each. Front back and side. First has unusual ribbed pattern on front and back. The second is a thick chunk (.5”) with wavy pattern on front and smooth on back. 

[Fin Lover]

How thick is the first item?  My first thought was a piece of hypural bone, but I can't tell from the picture if it's too thick for that.  

[LynWil]

It is about a quarter of an inch thick at the thickest part. But tapers in thickness. I attached a better picture for reference. I was leaning towards hypural bone also. So glad you said that! Thanks for your help 

 

 

[Fin Lover]

Ok, that fits hypural bone.  The others look like some sort of osteoderms, but I don't necessarily recognize the patterns.

[CDiggs]

The third item looks to me like a fragment from the unfused end of a vertebra.

[Brandy Cole]

My opinion on the third item is a heavily worn holmesina osteoderm based on the shape and compact internal structure. 

 

I think the second item may be an osteoderm from a large freshwater turtle of some kind. The internal compact structure looks consistent with turtle osteoderms.

[LynWil]

I was thinking turtle shell also. But the pattern was really throwing me! Thank you so much for your help! 😊

Edited May 23 by LynWil

[CDiggs]

For comparison.

Holmesina Osteoderms in several states of wear.

Proboscidean vertebra posterior aspect, showing incomplete fusion of growth plate.