Archaeologists have found one of the biggest raptors ever, one that used to roam what is now Hell Creek in South Dakota. Hence, the name: Dakotaraptor. Discover reports that this beast was about 16 feet long with sickle-like claws of nearly 10 inches, making it one of the largest raptors known to exist. More formally, it's a dromaeosaurid, but the Lawrence Journal-World out of Kansas provides a more down-to-earth description of these bird relatives: a "massive, freaky-looking carnivorous dinosaur-bird." Researchers found the partial skeleton in what's known as the Hell Creek Formation, rocks rich in fossil specimens, and date it to about 66 million years ago.
"This Cretaceous period raptor would have been lightly built and probably just as agile as the vicious smaller theropods, such as the Velociraptor," says the lead author of the paper in a release from Kansas University. Dakotaraptor would have been too big to fly, but it seems to have had feathers—its forearms had what researchers call "quill knobs" where feathers would be attached. That would make it the largest dinosaur found to date with wings, notes Discover. Another researcher speculates on the wings-but-no-flight quirk: "Either it evolved from an ancestor that could fly but had lost the ability to fly, like an ostrich, or dinosaurs evolved big quill-pen feathers for another reason, such as display or egg brooding." (Scientists had to use unusual means to salvage the skull of a rare baby dinosaur.)