A giant crocodile that walked on its hind legs roamed the warm, wet region of what's now North Carolina 231 million years ago, ripping through the armored shells of its prey like cake. Thankfully, the 9-foot-long Carnufex carolinensis, or "Carolina Butcher," went extinct by the end of the Triassic Period, about 200 million years ago. A skull, spine, and arm from the beast were discovered in a quarry a decade ago, but researchers only recently realized their significance. "When we got the bones out and prepared them, we found out that it was actually a really cool species," study author Lindsay Zanno tells the Washington Post. "It was one of the oldest and largest members of crocodylomorph—the same group that crocodiles belong to—that we've ever seen." Most crocodile relatives from the period were much smaller, about the size of a fox.
The beast, which lived before the supercontinent Pangaea broke apart, had a long skull resembling a knife, plus sharp, bladelike teeth it used to devour armored reptiles and early relatives of mammals, LiveScience reports. It was also "a bit of a Frankenstein," Zanno explains. Its skull is similar in size to other reptiles of the Triassic Period known as rauisuchids, but also similar to today's crocodiles in that it's "highly ornamented with bumps and grooves," Zanno tells Smithsonian. Its cheekbones and the shape of its teeth are more like those of meat-eating dinosaurs known as theropods. Though the "Carolina Butcher" eventually fell as dinosaurs rose up, "it was clearly a top predator" and "that's a niche we didn't know animals like this were filling," Zanno says. A researcher notes the find "pushes back the date of crocodylomorphs in the fossil record" and "changes our thinking on what these early crocodiles looked like and what they did." (A newly found dinosaur had a neck like a crane.)