Most dinosaur groups are stereotyped by the first found or the largest. Stegosaurus is the only stegosaur in the mass media, Tyrannosaurus the only tyrannosaur, Brontosaurus the only sauropod, etc. I’m sure Ankylosaurus is the only armored dinosaur known to most people-it’s the last, it’s the largest, it’s the first to be found, and it was a neighbor to Tyrannosaurus rex. However, ankylosaurs had existed for almost 100 million years before Tyrannosaurus. In fact, we’re going to look at two genera dating back to the time of Brontosaurus in the late Jurassic period, and lived alongside the giant sauropods and Stegosaurs. They are the first ankylosaurs-the smallest and most primitive known, but already well-armored and distinctively ankylosaurs.