Prehistoric Reptiles That Lived Before Dinosaurs

Discover a species of prehistoric reptiles that lived before the rise of the dinosaurs.

Jul 21, 2023By Tamara Bray
prehistoric reptiles  that lived before dinosaurs

Did you know that before the rise of the mighty Tyrannosaurus Rex and the cunning Velociraptor, there were a species of prehistoric reptiles that ruled the earth between the Permian and Triassic periods? Discover who these prehistoric reptiles were and how they lived.

The Scutosaurus

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3D Rendering of a Scutosaurus

The Scutosaurus was a reptile that lived in Russia during the Permian period, which is around 300 million years ago. Many Paleontologists believe that this reptile is the great ancestor of the turtle.

The conditions of the Permian period were favorable for this reptile as the days were typically warm and hot.

Thanks to these warm conditions, the earth at this time saw a rise in reptiles like the Scutosuarus and the Hylonomus. However, this meant a decline in amphibians because of the hot climate.

Scientists were able to pinpoint the birthplace of the Scutosaurus thanks to fossil remains found at various locations throughout Russia. There are currently seven fossil sites in Russia, many near the Sokolki Assemblage Zone of the Malokinelskaya Formation, which is close to the Ural Mountains.

While the Scutosaurus was the biggest reptile during the Permian period, their large body and small legs made them very slow. This meant that they were particularly vulnerable if attacked. To make up for this, the Scutosaurus had very thick skin covered in bony plates with exceptionally strong muscles making them very well-armored.

It is believed that these large armor-plated reptiles were herbivores with a diet that consisted of plants found along shorelines and river beds. Low-lying branches and leaves meant that they could use their flattened teeth to effectively grind branches and leaves to digest.

The Hylonomus

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Artist’s rendition of the Hylonomus 

The Hylonomus lyelli was discovered and given its scientific name by famous geologist William Dawson during the 1800s. Along the Joggins Cliffs, on the shores of Nova Scotia’s Bay of Fundy, Dawson discovered fossilized bones of the reptile Hylonomus.

This small reptile is believed to be over 300 million years old and was alive during the Permian period originating from Canada.

These reptiles were only 8 inches in length with small sharp teeth, which led scientists to believe that the Hylonomus should look pretty similar to our modern-day lizards, like Skinks, and were very good at climbing trees.

Thanks to the location of their fossils, scientists now believe that these small lizards lived in forested areas. In fact, their name means “forest wanderer.” Their sharp teeth were used to capture insects or millipedes.

The reason why the Hylonomus thrived during the Permian period, as opposed to amphibians, is because they were able to move away from water and could lay eggs on land, thus leading to their successful evolution.

The Dimetrodon

The Dimetrodon 

The Dimetrodon is a prehistoric reptile that is the most well-known due to its unique sail on its back, and while many people may think that it’s a dinosaur, the Dimetrodon is actually a reptile.

These large mammal-like reptiles lived during the Permian period as well, most likely during the early period around 260 million years ago.

Dimetrodon fossils have been found across North America in places like Canada and Texas, as well as Europe, which means that this reptile was able to thrive in different climates and environments.

These reptiles were around 130 inches in size and weighed at least 550 lbs. They supported their weight by walking on all four legs and had a massive fin that looked like a sail on their back.

Scientists believe that this fin is what helps the Dimetrodon with thermal regulation by absorbing the sun. Dimetrodons were cold-blooded reptiles which meant that they needed warmth to survive.

Their large sail helped cool them down and warm up quickly, which is why they evolved and survived much faster than other reptiles at the time.

However, towards the end of the Permian period, a meteorite hit the Earth. This one was over 180 million years before the second meteorite that killed the dinosaurs. The Dimetrodon became extinct during that time due to devastating volcanic eruptions.

The Lystrosaurus

The Lystrosaurus

With the extinction of the Dimetrodon, a new species of prehistoric reptile ruled the Earth during the late Permian and early Triassic periods. They were called the Lystrosaurus.

The Lystrosaurus was a type of therapsid, which was a mammal-like reptile, and from the Lystrosaurus evolved the first kind of mammals. Fossilized remains of this reptile have been found across South Africa, India, and even Antarctica, while most of the fossils were discovered in the Karoo Basin, South Africa.

These reptiles were around 36 inches and weighed around 100 lbs. Many scientists refer to this reptile as a shovel lizard because it would use the two tusks on the side of its head to dig out vegetation.

At one point after the Great Dying, this was a period of extinction for many reptiles. The Lystrosaurus made at least 90% of land vertebrates and had no real threat for a while, making them the most successful reptile that lived before dinosaurs.

To learn more about dinosaurs, check out our list of animals that lived alongside dinosaurs.

Tamara Bray
By Tamara Bray

Tamara is an animal lover from South Africa with years of experience researching and writing about reptiles of all sizes. She has three dogs, Lulu, Ciri, and Rafiki, all from a rescue organization. In her spare time, Tamara likes to go on trail walks and often has her nose buried in a book.