An artist's rendering of the Dakotaraptor. (Emily Willoughby/Kansas University)
An artist’s rendering of the Dakotaraptor. (Emily Willoughby/University of Kansas)

Imagine an ostrich with huge sickle-like claws, long powerful legs and a dinosaur’s toothy grin. Now double its height and give it a taste for flesh.

This is the Dakotaraptor, one of the biggest and likely the freakiest-looking predators to roam the Midwest 66 million years ago.

The newly discovered fossil was described in a study published by the University of Kansas Paleological Institute last week. Fittingly for this massive frankenpredator, the bones were found in a place called the Hell Creek Formation, among South Dakota’s otherworldly badlands.

The Dakotaraptor, a cousin of the turkey-sized velociraptor and an ancestor of modern birds, was one of the largest of its kind, researchers say. The creatures were 17 feet long from nose to tail and their wings — which were largely decorative — extended three feet from their bodies. The only raptor known to grow bigger was the 23-foot Utahraptor, which wrapped up its reign over the western U.S. roughly 60 million years before the Dakotaraptor arrived on the scene.

Like many of its relatives, Dakotaraptor was feathered. The fossils discovered in South Dakota show tiny “quill knobs” on the lower arm bones; in modern birds, those knobs are where feathers attach to the bone. The Dakotaraptor was much too large for flight — fortunately for the rest of its late Cretaceous fellows — but the knobs suggest that it descended from a line that could fly, or was perhaps on its way toward evolving to do so.

Dakotaraptor is the largest dinosaur ever found with true wings, Discover reported, though its not clear why the species hung onto the large appendages. They may have been used to shield eggs and young from predators, aid with hunting or attract mates, the researchers theorize. Or maybe they just looked intimidating.

Flightlessness aside, the Dakotaraptor would have been a fearsome predator. Its long legs made it a better and faster runner than the other big meat-eater at the time, Tyrannosaurus, and it may have hunted in packs. The dinosaur also boasted claws the size of a human hand.

According to the study’s authors, the Dakotaraptor filled a key niche in the sub-tropical swampy world that was late Cretaceous South Dakota. It was smaller than Tyrannosaurus but larger than most of the other carnivorous critters at the time, and it was built for longer pursuits, meaning it could catch fast-running prey that eluded other predators.

Since the Dakotaraptor fossils date to the very end of the late Cretaceous, the dinosaur likely died during the extinction event that wiped out the Dromaeosauridae (the family of feathered dinosaurs to which it belonged) and about three quarters of all other life on Earth 65 million years ago. Bad news for the Dakotaraptor, but good news for anyone living in South Dakota today.