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Edaphosaurus

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Edaphosaurus was a significant genus of extinct animals that lived a very long time ago.

Edaphosaurus pogonias
Edaphosaurus pogonias

These creatures lived during the Late Carboniferous and Early Permian periods. This time was roughly 303.4 to 272.5 million years ago. They lived in areas that are now North America and Europe. Edaphosaurus is an important part of history because it was one of the earliest large herbivores. A herbivore is an animal that eats plants. It was also an amniote tetrapod. This means it was a four-legged vertebrate that could live on land.

Edaphosaurus Scale
Edaphosaurus Scale

The body of Edaphosaurus was built for a life of eating tough plants. These animals could grow quite large. Some species weighed more than 300 kg. Their bodies had several distinct parts. They had short, robust limbs and a wide ribcage. The cervical vertebrae, which are the bones in the neck, were quite short. This was because their heads were very small compared to their bodies. The dorsal vertebrae, or the bones in the back, were massive. They also had a deep tail to balance their weight.

Edaphosaurus-cruciger jconway
Edaphosaurus-cruciger jconway

Eating was a complex process for Edaphosaurus. Their heads were small, triangular, and relatively broad. The front of the jaws had marginal teeth with serrated tips. These sharp edges helped them crop pieces from terrestrial plants. Inside the mouth, they had something very special. The back of the roof of the mouth and the inside of the lower jaw held dense batteries of peglike teeth. These formed a broad, crushing surface known as tooth plates.

To use these plates, the animal used propalinal jaw movements. This means the jaws moved from the front to the back to grind food. Because they ate plants, they likely had a large gut. This gut probably contained symbiotic bacteria to help break down cellulose. Cellulose is the tough material found in plant cell walls.

The most famous feature of Edaphosaurus was the sail on its back.

Boston Edaphosaurus
Boston Edaphosaurus

This sail was supported by extremely long neural spines. These are bones that grow upward from the vertebral column. The spines stretched from the neck to the lumbar region. Unlike the sail on the predator Dimetrodon, the spines of Edaphosaurus had small cross-bars. Scientists are still debating why these animals had such large sails. Some suggest the sail helped control body temperature. Others think it was used for display to recognize other members of the species. Some even proposed it could have helped with camouflage or fat storage.

Edaphosaurus-Field Museum
Edaphosaurus-Field Museum

We know much about Edaphosaurus thanks to paleontologists. Edward Drinker Cope first described the animal in 1882. He found the first fossils in the Texas Red Beds. He named the genus Edaphosaurus, which means "pavement lizard." This name refers to the dense "dental pavement" of teeth in its mouth. Cope originally thought the animal was a member of the Pelycosauria group. He even created the family Edaphosauridae to classify them. Later, he mistakenly created a separate genus called Naosaurus. He thought Naosaurus had a sail like a ship's mast. We now know that Naosaurus fossils actually belong to Edaphosaurus.

Different species of Edaphosaurus show how these animals changed over time. For example, Edaphosaurus cruciger was a very large species. Another species, Edaphosaurus boanerges, was named by Alfred Romer and Llewellyn Price in 1940. The name "boanerges" is an ironic reference to a very small jaw found in a fossil. There was also Edaphosaurus colohistion, which was an early species with a smaller sail. Scientists have noticed a trend in these species. Over time, the projecting processes on the spines became larger and more elaborate. This shows how the anatomy of the group evolved.

Edaphosaurus belongs to a group called synapsids. This group is very important because it includes the ancestors of mammals. Studying their bones tells us about how they lived. By looking at bone histology, which is the study of bone tissue, scientists found something interesting. Edaphosaurus grew much more slowly than the predator Dimetrodon. This suggests that Edaphosaurus had a lower metabolism. A metabolism is the process by which a living thing uses energy. While they were slow growers, their large sails grew very quickly. The bony tubercles on the spines grew rapidly over just a few seasons.

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🖼️ Images & Media (14)
File:Edaphosaurus NT small.jpg
Edaphosaurus NT small.jpg
File:Edaphosaurus Scale.svg
Edaphosaurus Scale.svg
File:The_Osteology_of_the_Reptiles_p50.png
The_Osteology_of_the_Reptiles_p50.png
File:Boston Edaphosaurus.jpg
Boston Edaphosaurus.jpg
File:Edaph boanerg2.jpg
Edaph boanerg2.jpg
File:Edaphosaurus-cruciger jconway.jpg
Edaphosaurus-cruciger jconway.jpg
File:Ed novomexicanus1DB.jpg
Ed novomexicanus1DB.jpg
File:Edaphosaurus pogonias.jpg
Edaphosaurus pogonias.jpg
File:Edaphosaurus-Field Museum.jpg
Edaphosaurus-Field Museum.jpg
File:The_human_side_of_animals_(7409100774).jpg
The_human_side_of_animals_(7409100774).jpg
File:Natural history (1919) (14779409184).jpg
Natural history (1919) (14779409184).jpg
File:The life of a fossil hunter BHL19032104.jpg
The life of a fossil hunter BHL19032104.jpg

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