Utahraptor

Utahraptor is the oldest known, and largest, of the dromaeosaurids. One of the most unique aspects that Utahraptor shares with its more famous cousin Velociraptor is that both had a lethal killing claw on each foot. Each inside toe had a large (about 10 inches) hooked claw that was controlled by a strong tendon. This claw was held upward when the animal was walking or running. When it attacked, however, the tendon snapped tight and the claw clamped down with great speed and force, slicing deeply into its victim. Not a very pretty picture, but an effective way to inflict a serious wound. Its hand claws were proportionally larger than other family members and Dr. Kirkland speculates that its hand claws were probably as important a weapon as the killing claws on its feet.

More real-life information: Utahraptors at Wikipedia.

Appearance
The Utahraptor of Jurrassic Turok is very close to the same size as the actual Utahraptors. The Utahraptor of Turok has a few headfeathers unlike the Velociraptors, although real Utahraptors had a full coat of feathers and even wing feathers on their arms.