March 15, 2021 at 8:00 am Some 260 million years ago, before the rise of dinosaurs, bone-crushing anteosaurs reigned as land’s largest predators. A new analysis of an anteosaur skull suggests that these hefty reptiles may have been relatively speedy. “This contradicts what we knew about anteosaurs before,” says Ashley Kruger, a paleontologist at the Swedish Museum of Natural History in Stockholm. Based on the reptiles’ size, which was around that of today’s hippos or rhinos, researchers had pegged the Permian Period predators as sluggish beasts that waited to ambush prey. The skull of an Anteosaurus magnificus appears to tell a different story.