Period

Dinosaurs lived during the Mesozoic Era (from 248 to 66.4 million years ago). The Mesozoic Era is divided as follows:

• The Triassic
  • Early (248 to 235 million years ago)
  • Late (235 to 208 million years ago)
• The Jurassic
  • Early (208 to 178 million years ago)
  • Middle (178 to 157 million years ago)
  • Late (157 to 144 million years ago)
• The Cretaceous 
  • Early (144 to 97 million years ago)
  • Late (97 to 66.4 million years ago).

 Dinosaurs first appeared in the Late Triassic Period.