A nice onchopristis (sawskate)  rostrum barb.
 
The "barbs" would have been used to aid with hunting prey items.
Onchopristis could grow up to 13 feet, but despite its huge  size, the fossil record shows it was still on the menu for Spinosaurus.
 
Specimen Details 
 
Location: Kem Kem Beds
 
Age: Approximately 95 million years old
 
Length: 1.77 inches