This bright colourful fun to learn jigsaw is a great way to discover fascinating facts about dinosaurs the puzzle shows the deadliest dinosaurs from the triassic jurassic and cretaceous eras the triassic period includes the arizonasaurus believed to be distant relatives of crocodiles the jurassic period shows the well known stegosaurus first fossils discovered in colourado in 1876 whilst the cretaceous period is dominated by the fearsome tyrannosaurus rex first fossil discovered in 1