Utahraptor

Utahraptor is a genus of large predatory theropod dinosaurs in the family Dromaeosauridae from the Early Cretaceous of what is now Utah, United States. It is the best-known and largest member of its family, represented by the species Utahraptor ostrommaysi. The genus name combines "Utah" with "raptor," a term used for dromaeosaurids. The species lived about 126 million years ago during the Early Cretaceous.

Estimates for adult length range from about 5.5 to 7 meters, with mass widely varied but typically thought to be several hundred kilograms. Its skeleton shows hallmark dromaeosaurid features: a long skull, powerful forelimbs with grasping hands, a long, stiff tail, and a large, recurved sickle-shaped claw on each second toe used for grasping and slashing prey. As with other dromaeosaurids, Utahraptor is presumed to have had feathers.

Fossils were discovered in 1991 in the Cedar Mountain Formation near Moab, Utah, and described in 1993. The remains indicate it was one of the largest predatory dinosaurs known from North America at the time. The ecology of Utahraptor suggests a floodplain environment with a variety of herbivorous dinosaurs as potential prey. Debate continues about whether Utahraptor hunted alone or in groups; there is no direct evidence for pack behavior, and such interpretations remain speculative.

Utahraptor has a significant place in the paleontological record as an exemplar of a large, feathered dromaeosaurid, contributing to understanding of predatory adaptations and the diversity of Early Cretaceous theropods in North America.