Eryops megacephalus

Last updated: May 27, 2024
Verified by: AZ Animals Staff
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Unlike modern amphibians, Eryops had a well-developed rib cage


Eryops Scientific Classification

Scientific Name
Eryops megacephalus

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Eryops Conservation Status

Eryops Locations

Eryops Locations

Eryops Facts

Fish, small reptiles, and other amphibians
Fun Fact
Unlike modern amphibians, Eryops had a well-developed rib cage
Most Distinctive Feature
Eryops had a long, drawn-out face
Distinctive Feature
Eryops had a massive head
Marshlands, swamps and other locations close to water bodies
Orthacanthus, Dimetrodon
Extinct amphibian
Special Features
Eryopds had long and large skulls
Number Of Species
North America

Eryops Physical Characteristics

440 pounds
4.9–9.8 feet

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Eryops is a genus of extinct, primitive amphibians that lived in the swamps of the Permian Period (about 299 to 251 million years ago). It is an ancient relative of modern-day amphibians, such as frogs, toads, and salamanders. The Erypops looked more like a giant salamander than a toad. 

Description and Size




amphibian was massive and stout, weighing 440 pounds, and was mostly about 4.9 to 6.6 feet long.


Eryops is a genus of extinct, semi-aquatic animals that lived during the Late Carboniferous. It contains the single species, Eryops megacephalus. The fossils of this amphibian are found mainly in Early Permian rocks in New Mexico and the eastern United States. Eryops, the genus name, is a Greek word that means “drawn-out face,” while “megacephalus,” the species name, translates to “big head.” The two terms refer to the long and large skull of this animal.

The amphibian was massive and stout, weighing 440 pounds, and was mostly about 4.9 to 6.6 feet long. However, it could grow to a maximum length of 9.8 feet with a 2-foot extended skull and a short, stiff tail. The limbs were robust, even though they were short, and the shoulder and hip girdles were enormous. The Eryops had the most heavily ossified skeleton of its relatives and was among the largest land animals of its time. 

Eryops had well-developed ribs. This is a fascinating trait considering the fact that most amphibians have small ribs or none at all. Generally, amphibians don’t need ribs since they breathe through their skin like modern salamanders and frogs.

Evolution and History 

Eryops evolved from lobe-finned fish in the Early Permian about 295 million years ago, making it one of the earliest amphibians ever to evolve. Despite being an amphibian, it retained many characteristics of its Piscean ancestors, along with adaptations that made life on land possible.

For instance, they had lungs instead of gills for taking in air on land. But the rib cage was not developed enough to expand and draw in air. Scientists think the animal had to move the floor of its mouth with an up-and-down motion to pump air. 

The most significant adaptation that made life on land possible for this primitive amphibian was its limbs. The Eryops‘ limbs were just slightly strong enough to keep its body off the ground. The hind legs were particularly important. In addition to supporting the animal’s weight on land, it would have also provided propulsion in the water. 

Still, walking on land would have been very difficult, and the animal was most likely very slow. It moved with very short board strides. Preserved fossilized footprints confirm the Eryops and many of the other early amphibians that evolved after it most likely moved this way. Animals with longer and more erect limbs would not evolve until tens of millions of years after the Eryops extinction. 

The Eryops’ life represents a crucial step in the evolutionary history of living organisms as it demonstrates the gradual transition from life in the water to life on land.

Diet—What Did Eryops Eat?

The carnivore was one of the giant terrestrial predators of its era, and its 2-foot-long head, armed with razor-sharp teeth, was an effective hunting tool. Eryops ate fish, small reptiles, and other amphibians. There were also a lot of terrestrial invertebrates around during the period, which would have provided enough food.

Typically, the carnivore would position itself with its jaws open and wait patiently. When a prey moved close to its mouth, the Eryops would snap its jaws shut like an organic bear trap, holding the target in place while it methodically gnawed on it. Despite the lack of a chewing mechanism, the animal could clutch its prey and squeeze it before throwing it farther into its mouth. This feeding behavior is seen in alligators and crocodiles today. 

Habitat—When and Where Did Eryops Live?

Eryops was a primitive amphibian, suggesting it spent part of its life on land and water. It was one of the earliest amphibians to spend a significant amount of time in terrestrial habitats. The size and robustness of the vertebral column and the skeletal elements of the limbs suggest that Eryops was well adapted to moving on land. However, the Eryops still lived close to the water, where food was more abundant. 

Additionally, because soft amphibian eggs lack shells and are susceptible to drying up, they would have needed to lay their eggs in highly wet environments the way modern amphibians do. This means Eryops would have required a body of water to breed. They deposited shell-less eggs, which would have developed into aquatic larvae. However, unlike many modern amphibians, the young larvae did not go through the different stages of metamorphosis. 

Eryops—Threats and Predators

Eryops was one of the largest land animals of its time. Given its massive size, this animal didn’t have to worry about predators on land or in the water. However, they were poor swimmers and were sluggish on land as well. Eryops would have needed most of its strength to lift its body off the ground. This sluggish, challenging, and predator-vulnerable early-walking motion probably exposed this amphibian to some level of risk while on the ground. Also, predators like the Orthacanthus, a massive carnivorous prehistoric shark, might have hunted it underwater. The Dimetrodon, a more prominent inland species, may have also preyed on this amphibian.

Discovery and Fossils

The exact person who discovered the fossils of this species is not known. However, E. D. Cope named it in 1887 based on its drawn-out, elongated head. The teeth and skull bones of Eryops are the most frequently discovered fossils, most commonly found in Lower Permian rocks. Although several entire skeletons of Eryops have been discovered in the aforementioned rocks, Eryops‘ most prevalent remains are still the skull bones and teeth. Archer County, Texas, is where most of the Eryops fossils were discovered. Additional finds have been made in the Late Carboniferous rocks in New Mexico.

Extinction—When Did It Die Out?

The Eryops megacephalus went extinct between 310 and 295 million years ago. It lived during the Early Permian Period. This amphibian went extinct before the Permian-Triassic extinction event. The extinction event, known as the “mother of all mass extinctions,” occurred about 251 million years ago. 

Similar Animals to the Eryops

Similar animals to Eryops include:

  • Cheliderpeton — This animal is an extinct member of the temnospondyl group of amphibians that lived during the Early Permian period. Cheliderpeton was roughly 25.5 inches and had a 6.3-inch skull.
  • OnchiodonOnchiodon is an extinct amphibian genus that mostly lived in Europe during the Carboniferous and Permian periods. Some members of this genus also existed in North America around the time. 
  • Clamorosaurus — An extinct amphibian that lived about 272.5 million years ago, Clamorosaurus fossils have been discovered in Russia. They are close relatives of the Eryops and have a similar appearance. However, with a length of about 9 inches, Clamorosaurus was significantly smaller than the Eryops
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Abdulmumin is a pharmacist and a top-rated content writer who can pretty much write on anything that can be researched on the internet. However, he particularly enjoys writing about animals, nature, and health. He loves animals, especially horses, and would love to have one someday.

Eryops FAQs (Frequently Asked Questions) 

When was the Eryops alive? 

The gigantic amphibian lived in what is now present-day North America during the Early Permian Period. It lived between 299-255 million years ago.


From what did the Eryops evolve?

Eryops evolved from lobe-finned fish and kept many of its traits while adapting them for life on land. Eryops had a wide mouth and a huge head compared to its body, like some other fish.

How big was Eryops?

Eryops was among the largest land creatures of its era, with an average length of just over 4.9 to 6.6 feet. However, it could grow up to a length of 9.8 feet. It weighed roughly 200 pounds on average.


Who discovered Eryops?

The discoverer of Eryops is unknown. However, E. D. Cope named it in 1887 based on its large, drawn-out head. The fossils of these predators were discovered in the mid-nineteenth century in the Texas Red Beds. They were only found in Early Permian Period rocks.

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  1. Prehistoric Wildlife / Accessed November 21, 2022
  2. Fossil Fandom / Accessed November 21, 2022
  3. Wikiwand / Accessed November 21, 2022