Meet the Large Dinosaur Discovered by a 7-Year-Old

A Chilesaurus diegosarez skeleton (model)
© CC BY-SA 4.0

Written by Dayva Segal

Updated: October 21, 2023

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Doesn’t every seven-year-old wish they could be a paleontologist and discover a new dinosaur species? Well, for one seven-year-old in Chile, that dream actually came true! In 2004, Diego Suarez went with his parents, geologists Manuel Suarez and Rita de la Cruz, to study rocks in Patagonia. This region is on the southern tip of South America and is part of both Chile and Argentina. While on the trip, a dinosaur was discovered by Diego. He found a rib and vertebrae and ran to his parents to tell them. They took the samples and sent them to Argentinean paleontologists who specialize in dinosaur bones.

At first, experts thought the bones belonged to a few different species. But they soon realized it was a new species of dinosaur that had never been discovered before. They found full skeletons with shocking results—this dinosaur, named the Chilesaurus, isn’t like any that have been found before.

Scientists think the location may have been the site of a Chilesaurus nest. They found many small specimens, not much bigger than a chicken. However, they also found specimens that lead them to believe the largest Chilesaurus could have been up to 10 feet long. They believe the small ones were probably babies or young Chilesauruses.

Why is it Called a Chilesaurus?

The dinosaur is named Chilesaurus, since it was found in Chile. The scientific name is Chilesaurus diegosuarezi‭, after the boy who found the initial bones that led to the discoveries. Diego is officially the youngest person to discover a fossil of a previously unknown species and he holds the Guinness World Record title to prove it!

Even though Diego found the first Chilesaurus bones in 2004, the dinosaur wasn’t officially named until 2015. It wasn’t until scientists went back to the area to find more specimens that they discovered it was a new species.

What Makes the Chilesaurus So Different?

The intact skeletons of Chilesaurus led to some astonishing discoveries. This dinosaur has vertebrae similar to the fearsome carnivores like Tyrannosaurus Rex and velociraptors from the theropod family. However, its feet, ankles, and pelvis resemble a different branch of herbivorous dinosaurs, ornithischians. They also have a large claw on their hands, likely used for defense, like sauropodomorphs.

Despite having similarities to meat-eating dinosaurs, the Chilesaurus was an herbivore. It has flat, forward-pointing teeth that could have been useful to snip or strip plants. Its pelvic bone points backwards, allowing more room in the gut for larger plant meals. Their legs were also not well-adapted for running. Their predator ancestors had to run fast to catch prey, but the Chilesaurus had legs that would be better for walking (and munching on plants).

Experts believe that the Chilesaurus is actually a genus of dinosaurs. So far, the only species they have discovered is the Chilesaurus diegosuarezi.

3D artist rendering of Chilesaurus

A 3D artist’s rendering of a

Chilesaurus diegosuarezi

reveals what this animal may have looked like.

© – Original

What Are Theropods, Ornithischians, and Sauropodomorphs?

These are three different clades of dinosaurs. A clade is a group of living things that experts believe have evolved from a common ancestor. Within each clade, there can be several different subgroups and species.


The name theropod means “wild beast foot” in Greek. What ties theropods together is that they have hollow bones and three clawed toes on each of their limbs. Besides this, they had a lot of varying qualities. Some had large scales, others had small ones. Certain theropods may have had a feather-like covering only when young, others may have had these feathers throughout life. Some species were as small as 1 foot long, while others grew to be 46 feet long.

As mentioned, some of the most ferocious carnivores of the dinosaur world were theropods. However, some did develop into herbivores and omnivores. Some theropods specifically ate only fish or insects.

Examples of theropods are the tyrannosaurus rex and the giganotosaurus.

Fun fact: today’s birds are theropods. They are literally dinosaurs!


Ther term ornithischia means “bird hipped” in Greek. Even though birds are technically theropods, this clade of dinosaurs had hips similar to today’s birds. Ornithischians also had a special bone called a predentary that allowed them to easily clip plant materials. Some experts also believe that a beak may have been attached here. However, Chilesaurus did not have this bone. Experts believe this may be because Chilesaurus was one of the first ornithischians and had not developed this bone yet.

Ornithischians also had other features that group them together, like cheek teeth shaped like leaves, teeth that came together for grinding plants, tendons near the pelvis that hardened into bone, and five or more vertebrae attached to their pelvis.

Examples of ornithischians include triceratops and stegosaurus.


Sauropodomorph means “lizard footed form” in Greek. This clade included sauropods—long-necked, herbivorous dinosaurs. The features of this clade include:

  • Long necks
  • Weak teeth
  • Teeth shaped like either leaves or spoons
  • Stomach stones to digest plant matter
  • A downturn at the front of the upper mouth which may have had a beak attached
  • Three or more sacral vertebrae, 10 or more cervical vertebrae, and 25 presacral vertebrae
  • Large nostrils
  • A large claw on their thumb

Many sauropodomorphs were huge, like the Argentinosaurus which could have been up to 131 feet long. Other examples of sauropodomorphs include diplodocus and Plateosaurus.

Chilesaurus diegosuarezi.jpg skeleton on display

This is a skeletal mount of

Chilesaurus diegosauezi


©CC BY-SA 4.0. – Original / License

Is Chilesaurus a Theropod?

Scientists have gone back and forth on this issue. At first, they did believe that the Chilesaurus was a theropod. Even though most theropods are carnivores, there have been other times in dinosaur evolution that theropods evolved an herbivorous species or two like the caudipteryx and the erlikosaurus.

However, after a few years of study, other scientists argued that they are not therpods. Instead, they believe Chilesaurses are ornithischians. Some experts believe they may be “basal ornithischians” meaning they may have been some of the original ornithischians!

In general, there is no official agreement on exactly what Chilesaurus is. Some people believe they are theropods, others believe they are ornithischians, and still others think they might even be sauropodomorphs. Since they have qualities of each of these extinct clades of dinosaurs, it may take the discovery of more fossils and more study to reveal the truth.

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About the Author

Dayva is a writer at A-Z Animals primarily covering astrology, animals, and geography. She has over 12 years of experience as a writer, and graduated from Hofstra University in 2007 with a Bachelor of Science in Music and a Minor in French. She has also completed course work in Core Strengths Coaching, Hypnotherapy, and Technical Communication. Dayva lives in the SF Bay Area with her cute but very shy cat, Tula.

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