Utahraptor

Utahraptor (meaning "Utah's predator" ) is the largest known member of the theropod dinosaur family Dromaeosauridae, and dates from the upper Barremian stage of the Early Cretaceous period (132-119 million years ago).

Discovery
James Kirkland, Rob Gaston, and Don Burge discovered Utahraptor in 1991 in Grand County, Utah, within the Cedar Mountain Formation. The type specimen is currently housed at the College of Eastern Utah Prehistoric Museum, although Brigham Young University currently houses the largest collection of Utahraptor fossils.

The type species (and only known species of Utahraptor), Utahraptor ostrommaysi, was named for the American paleontologist John Ostrom, from Yale University's Peabody Museum of Natural History, and Chris Mays, of Dinamation International. Sculptor Raymond Persinger was included in James Kirkland's original abstract referencing Mr. Persinger's concepts regarding the claw structure. The holotype of Utahraptor is fragmentary, consisting of skull fragments, a tibia, claws and some caudal (tail) vertebra. The few elements suggest an animal about twice the size of Deinonychus. Like other dromaeosaurids, Utahraptor had a huge curved claw on the second toe, one is preserved at 22 centimeters (8.7 in) in length and is thought to reach 24 centimeters (9.4 in) restored. Up to 6.5 m (21 ft) long, 2 m (6.6 ft) tall, and 700 kg (1,500 lb) in weight, Utahraptor would have been a formidable predator.

It is thought that Utahraptor may be closely related to the much smaller Dromaeosaurus and the giant Mongolian dromaeosaurid Achillobator.