City of Mesa, AZ

Arizona Through Time

Model of Postosuchus vs. Placerias

Triassic Petrified Forest and Wetlands
Postosuchus (left), a carnivore, confronts Placerias, a herbivore in the Late Triassic forest of Arizona, 225 million years ago. These animals lived in the forests that today we know as the “petrified forest” of northern Arizona.

Buettneria bones

Buettneria was a large amphibian that lived in the wetlands adjacent to what are now the petrified forests. A lie-in-wait predator, Buettneria lived in the Late Triassic, 225 million years ago.

Leptosuchus skull

Leptosuchus is a phytosaur, a group of reptiles that resemble crocodiles but evolved their form independently. He, along with Buettneria inhabited the wetlands adjacent what are now the petrified forests of Arizona.

Model of Dilophosaurus

Kayenta Formation
Dilophosaurus is arguably the most famous dinosaur from Arizona. Notable for the two crests on its head, this predator lived in the Early Jurassic Period, about 200 million years ago. Dilophosaur remains and footprints have been found in the Kayenta Formation of northeastern Arizona.


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