Vert? reptile? amphib? fish? not a vert? SOLVED! - Orthacanthus tooth

[hadrosauridae]

OK, I need some help on a fossil I uncovered today.  Details: north-central OK, Permian (mid to lower), Wellington fm, in a slab of mud/sand stone with claystone inclusions and acid reactive.  Lots of plant material and partial tetrapod skull in this large slab.

 

With all that out of the way, I hope someone here can give me an ID on this tiny bugger.  Its roughly 4mm across.  I'm really at a loss for what this is.  The only thing that comes to mind is that it might be a vertebra.  The two processes (extension) are curved, giving it the appearance of an elephant skull.  You can see there is a fresh break at the centrum.  Before it broke, is was nicely rounded and whole.

 

So experts, what your opinion here?  Vert? reptile? amphib? fish? not a vert?

 

One last thing.  Both this, and the skull frag, have a weird deep red coating on the surface.  In a way if annoying as its a little harder to get through than the rest of the matrix, but then again I know when I'm getting very close to bone because of the color.

Edited April 13, 2020 by hadrosauridae
solved

[Troodon]

Orthacanthus shark tooth

[hadrosauridae]

25 minutes ago, Troodon said:

Orthacanthus shark tooth

dang that was fast!  Thank you good sir, I have my answer!