Sticking with a close-up theme, have you got any idea what this very distinctive bit of bone is from?
As usual, you can leave your suggestions, comments and questions below. If you find this too easy feel free to spice up your answer with some cryptic clues. Have fun!
Zygoma 
Tommy, can you hear me?
I suspect Castor can . ( hear Tommy that is )
We’d slap tails for that vote!
A quick squizz at the “Skulls Unlimited” site and I agree with Lee and Daniel and Dan. Weird structure: does some tendon or muscle go around it like a rope around a pulley?
Pretty sure that is canadensis rather than fibre too (going by the shape of the opening).