The eight foot long creature is related to Velociraptor, one of the terrifying stars of the movie Jurassic Park.
Like its famous cousin, Linheraptor had a large curved toe claw on each foot which may have been used to dispatch prey.
The 55lb dinosaur, which lived 75 million years ago, would have been agile and swift on its feet.
Mr Pittman and Jonah Choiniere from George Washington University came across the animal’s fossil bones sticking out of a cliff face.
The pair were visiting the Wulansuhai Formation, a site of red sandstone rocks in Inner Mongolia where a number of other dinosaur finds have been made.
Recalling the discovery, Mr Pittman said: “We were out there looking for fossils but this was like hitting the jackpot.
“Jonah saw a claw protruding from the cliff face. I’m surprised nobody in London heard us shouting we were that excited.
“I’ve always wanted to discover a dinosaur since I was a kid, and I’ve never given up on the idea. It was amazing that my first discovery was from a Velociraptor relative.”