Dinosaurs weren’t the first giant plant-eaters to roam the Earth; that frontier was pioneered first among vertebrates by the dicynodonts, a group of tusked therapsids (the clade which includes modern mammals) which survived the Permian Mass Extinction and lasted to the end of the Triassic period. They ranged widely in size and distribution, from the diminutive Diictodon, to the pervasive Lystrosaurus, to giants like Lisowicia and Kannemeyeria.