SIOUX FALLS, S.D. — Tyrannosaurus rex may have been known as the big guy around the Hell Creek Formation 66 million years ago, but a newly discovered species of raptor would have roamed nearby as one of the region’s most lethal predators.

Dakotaraptor stood 6 feet tall at the hips, yet moved like a springy, agile sprinter, reaching 30 to 40 mph and rivaling today’s ostrich.

This sketch depicts the newly discovered species of raptor called Dakotaraptor. The fossils were unearthed from the Hell Creek Formation in northwestern South Dakota. Associated Press photos

Robert DePalma, curator of vertebrate paleontology at the Palm Beach Museum of Natural History in West Palm Beach, Fla., examines the fierce foot claw and other bones of a newly discovered species of raptor called Dakotaraptor, whose fossils were found in South Dakota.

But potential prey caught admiring the 17-foot-long creature’s grace stood little chance, as the strong-muscled winged Dromaeosaur boasted a vicious 91/2-inch-long killing claw that could make mincemeat out of any herbivore caught in its path, said Robert DePalma, curator of vertebrate paleontology at the Palm Beach Museum of Natural History.

“It had one of the strongest killing strokes in that slashing claw of any raptor known,” DePalma said.

DePalma and his research team including University of Kansas paleontologists announced the new species in a study published Oct. 30 by the University of Kansas Paleontological Institute.

Dakotaraptor helps fill a gap in body size distribution between the small bird-like Maniraptora creatures and the giant T. rex found in Hell Creek, which spans parts of northwestern South Dakota, southwestern North Dakota, eastern Montana and eastern Wyoming.

The newly discovered species roamed the earth alongside T. rex, the three-horned Triceratops and the duck-billed Edmontosaurus.

Thomas Holtz Jr., a senior vertebrate paleontology lecturer at the University of Maryland, said most of the raptor bones and teeth found in Hell Creek have been from small-form creatures.

“That is what is important about this find,” Holtz said. “In fact, it was rather bigger than most of us expected, almost the size of the largest known Dromaeosaurid, the much earlier Utahraptor.”

Dakotaraptor stands about as tall as Utahraptor, a species discovered in the 1990s in east-central Utah.

But the stockier Utahraptor, which lived about 60 million years earlier than Dakotaraptor, was an ambush predator with thicker bones and leg proportions that limited its speed, making it the “beefly bulldog of raptors,” DePalma said.

Dakotaraptor did not fly, which makes the presence of quill knobs on its arms so interesting. The bumps serve as reinforcement points for long wing feathers, marking the first concrete evidence that large raptors had wings.

“It really would have made this like a turkey from hell,” DePalma said.

Related Stories