Frill? Chunkosaurus?

[patrickhudson]

My three year old was playing with a box of random Dino bones this morning and he handed me this one - which I hadn’t really paid attention to before.  
It seems like they’re vessel grooves on the smooth surfaces?  I know it’s tough to see the symmetry on my pics, and I know it’s pretty chunkosaurus, but I didn’t know with the unique convex and concave surfaces including the unique surface texture if it was at all identifiable.   Unique shape.   Frill piece?  Unidentifiable?
judith river formation of northern Montana - milk river 
thanks folks 

[jpc]

Nice find... half of an ankyosaur scute (osteoderm).  Its texture is very similar to ceratopsian frill but the round shape and the huge keel... ankylosaur.  When I say ankylosaur, I am not distinguishing between ankylosaur and nodosaur.  

[TyBoy]

Nice scute even partially ones are cool

[patrickhudson]

Thanks for the quick reply guys.  I’m still having a tough time visualizing it, but I don’t think we’ve found anything like this before.  Always exciting to find something new.