Finally, in the long Upper Cretaceous, the greatest abundance and diversity of dinosaurs of all time lived in North America. During the early part of the Upper Cretaceous, the therizinosaur "Nothronychus" and the ceratopsian "Zuniceratops" lived. During the Campanian stage (83.672 mya), an enormous diversity of dinosaurs is known. Theropods included the tyrannosaurs "Albertosaurus", "Gorgosaurus", "Daspletosaurus", "Appalachiosaurus", and "Dryptosaurus", and the dromaeosaurids "Dromaeosaurus", "Saurornitholestes", "Atrociraptor", and "Bambiraptor". Ceratopsians, such as "Pachyrhinosaurus", "Styracosaurus", "Centrosaurus" "Monoclonius", "Brachyceratops", "Pentaceratops", and "Leptoceratops" also existed. Among hadrosaurs, "Parasaurolophus", "Corythosaurus", "Lambeosaurus", "Saurolophus", and "Prosaurolophus" existed. 