Cretaceous hadrosaurs. Computer illustration of the heads of a Tsintaosaurus sp. (right) and Saurolophus sp. (left) hadrosaurid dinosaur. Tsintosaurus grew to around 10 metres long and lived during the Campanian age (around 83 to 72 million years ago) of the Late Cretaceous period, in what is now China. Saurolophus grew to around 10 metres long and lived during the Late Cretaceous period (around 100 to 66 million years ago), in what is now North America and Asia.