6 Dinosaurs That Lived In Arizona (And Where To See Fossils Today)

Dilophosaurus Model
Mircea Moira/Shutterstock.com

Written by Kyle Glatz

Updated: April 20, 2023

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Although it may be hard to imagine, large portions of Arizona were once underwater millions of years ago. Fortunately, not every part of the state was wet. Paleontologists were able to recover fossils from sediments that were not eroded throughout history and record footprints from dinosaurs that wandered through the state’s dunes. Let’s look at six of the dinosaurs that lived in Arizona throughout its rich history.

The state dinosaur, the Sonorasauraus, is most likely the tallest dinosaur that roamed Arizona.

We’ll tell you all about the various species found in this area. We’ll start with a quick look at Arizona’s state dinosaur and then spend time looking at other reptiles that lived throughout the state.

What Is Arizona’s State Dinosaur?

Sonorasaurus thompsoni

The state dinosaur of Arizona is Sonorasaurus.

Arizona’s state dinosaur is Sonorasaurus. Only one specimen of this large brachiosaurid dinosaur was ever recovered. This creature was made the state dinosaur of Arizona in 2017.  A University of Arizona student named Rich Thompson found the bones in the Turney Ranch Formation back in 1994.

The Sonorasaurus was a very large dinosaur that measured about 50 feet long and 26 feet tall. Scientists believe that the creature could have weighed anywhere between 88,000 and 110,000 pounds.

This massive reptile was a quadruped and an herbivore, and it lived at some point between 112 and 93 million years ago. Now that we know a little bit about the Sonorasaurus, let’s see some of the other dinosaurs that once walked the land.

What Are The 6 Dinosaurs That Lived In Arizona?

A variety of dinosaurs lived in Arizona, and they left behind plenty of evidence of their existence. Unlike some states in the Midwest that lack any fossil evidence, paleontologists in Arizona have recovered dozens of great dinosaur fossils.

Let’s examine some of the most interesting species to emerge from this part of the U.S.

1. Chindesaurus bryansmalli


The Chindesaurus bryansmalli was bipedal and most likely a carnivore

Chindesaurus bryansmalli was a medium-sized saurischian dinosaur that lived sometime between 213 and 210 million years ago during the Triassic. The species was found in the Petrified Forest National Park in 1984.

Paleontologists didn’t know much about this dinosaur when it was recovered, hence the broad description as a saurischian dinosaur. However, a recent redescription of the holotype specimen suggests that the fossils belonged to a theropod.

Scientists believe this reptile measured from 6.6 to 13.1 feet long, stood about 3 feet tall and weighed anywhere between 50 and 100 pounds. The dinosaur was bipedal and most likely a carnivore.

2. Sarahsaurus


was probably a medium-sized dinosaur.

The fossils of Sarahsaurus were found in the Kayenta Formation around Gold Spring, Arizona. Many of the fossils were in very good shape, so scientists learned a great deal about this dinosaur. However, given the fact that it lived between 199 and 182 million years ago, some elements of the dinosaur remain a mystery.

As a member of the Sauropodomorpha clade, Sarahsaurus was probably a medium-sized dinosaur that grew about 10 to 13 feet in length and weighed about 400 pounds or slightly more.

3. Coelophysis bauri  

Coelophysis bauri was a theropod that lived about 228 to 201 million years ago. Fossils of this dinosaur have been found throughout several states in the American Southwest, especially in the Chinle Formation.

These dinosaurs could measure about 10 feet long and stood about 2.5 feet tall. One of these reptiles could weigh about 30 to 40 pounds. They are easily recognized by their elongated skulls.

4. Dilophosaurus wetherilli

Dilophosaurus Male 3D Render

The size of


made it one of the largest land animals during the Early Jurassic when it lived.

The actual Dilophosaurus is nothing like the creature seen in Jurassic Park. This bipedal carnivore was anything but small, and it didn’t have venom.

Members of this genus were large theropods. They could measure about 23 feet long including a long tail. Dilophosaurus wetherilli stood over 5 feet tall at the shoulder, and it could have weighed as much as 880 pounds. That size makes it one of the largest land animals during the Early Jurassic when it lived.

5. Segisaurus halli

Segisaurus halli was far more like the Jurassic Park interpretation of Dilophosaurus, at least in size. This dinosaur stood about 1.65 feet tall, measured about 3 feet long, and weighed between 8 and 15 pounds.

This dinosaur was a theropod, and it was discovered in Tsegi Canyon. No other dinosaurs have been discovered in that area.

6. Sonorasaurus thompsoni

Sonoroasaurus thompsoni is the state dinosaur of Arizona, and it’s one of the larger ones to roam the state. Fossils of this dinosaur were first found in 1994 by a graduate student named Richard Thompson.

This quadrupedal herbivore was a very large species of dinosaur. Estimates say that the dinosaur was about 49 feet long, 26 feet tall, and weighed between 88,000 and 110,000 pounds! While that is quite a large reptile, it’s small compared to other members of the Brachiosauridae family.

Scientists believe that this dinosaur lived between 112 and 93 million years ago. Given its large size, this may have been the largest of the dinosaurs that lived in Arizona.

The dinosaurs that lived in Arizona came in many shapes and sizes. Some of the fossils of these dinosaurs could not be adequately identified beyond their scientific family. Future discoveries of fossils and further exploration of existing collections will provide more information about the exact genera and species that lived here.

Where Can You See Fossils of Dinosaurs That Lived in Arizona?

Arizona has several museums dedicated to educating the public about dinosaurs. A great place to start learning about dinosaurs that lived in Arizona is the Arizona Museum of Natural History. The museum’s Dinosaur Hall is filled with different casts of dinosaurs that lived in Arizona as well as casts of dinosaurs that lived in other states.

You can find many different programs, events, and volunteer opportunities to help you get closer than ever to fossils and information about dinosaurs.

This museum is located in Mesa, Arizona. The museum is typically open from 10 a.m. to 5 p.m. on Tuesday through Saturday. However, it’s only open from 12 to 5 p.m. on Sundays and closed on Mondays.

The museum offers a virtual tour that allows you to experience many different collections without ever setting foot inside the building!

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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