Allosaurus sp.

Real Fossil - Jurassic 150 Mya - Warm Springs Ranch, Thermopolis Wyoming
The portion of this toe claw preserved is the bone core - the claw itself would have been covered in a durable, sharp sheathing in life. This sheath would have been made of keratin, the same material in human hair and nails. The large groove along the edge once contained a large blood vessel; kertain requires a large flow of blood to grow.