Hadrosaurs
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper Jurassic/Lower Cretaceous iguanodontian dinosaurs and had similar body layout. They were ornithischians.
Hadrosaurids are divided into two principal subfamilies. The lambeosaurines (Lambeosaurinae) had hollow cranial crests or tubes, and were generally less bulky. The saurolophines, identified as hadrosaurines in most pre-2010 works (Saurolophinae or Hadrosaurinae), lacked hollow cranial crests (solid crests were present in some forms) and were generally larger.
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