Dawn of the dinosaurs in the Petrified Forest

Photo: Christian Sidor/Burke Museum
Photo: Christian Sidor/Burke Museum
February 15, 2017 | Burke Museum

About 220 million years ago during the Late Triassic epoch, Arizona’s Petrified Forest National Park was on the western border of the supercontinent Pangea. Although now an arid desert, this landscape was once a lush rainforest home to some of North America’s earliest dinosaurs.

Christian Sidor, curator of vertebrate paleontology and UW Biology professor, is working with the National Park Service to survey the geology and paleontology of lands recently acquired by Petrified Forest National Park. Sidor’s team of graduate students and research associates are conducting an inventory of the fossils present and collecting specimens for research at the Burke Museum.

After two years of studying and collecting, Sidor’s team has found much more than the fossilized wood the park is famous for! They’ve found early carnivorous dinosaurs, armored reptiles called aetosaurs, giant salamander-like amphibians, crocodile-mimic phytosaurs and a new species of shuvosaurid—a bizarre, bipedal, herbivorous creature that is a distant relative of today’s crocodiles.

Sidor’s excavation of the new shuvosaurid promises to document a new species that will be the first of its kind in any museum collection in the world. To date, the team has collected parts of at least twenty individuals from a small bone concentration, with most of the animals' limbs and backbone represented. With luck, they will find a skull when they continue their excavations this summer.

The shuvosaurid is one fossil that is being prepared for display in the New Burke, opening in 2019. Another is Revueltosaurus, an herbivorous reptile that was long confused for North America’s first plant-eating dinosaur due to having the same type of teeth as plant-eating dinosaurs. But when a full skeleton of Revueltosaurus was found, it was clear the animal wasn’t a dinosaur at all.

This summer, Sidor’s team will be collecting large slabs from a bonebed containing Revueltosaurus for a special display outside of the New Burke’s fossil lab. Our new lab will show the visitor what a fossil looks like in the field and how Burke volunteers can make real contributions to research in paleontology!


Christian Sidor is curator of vertebrate paleontology and associate director of research and collections at the Burke Museum. He is also a professor of biology at the University of Washington.

See more from vertebrate paleontology and learn more about the team!