Edaphosaurus, one of the earliest known large amniote tetrapods, is an extinct genus of edaphosaurid synapsid. The genus was first described by Edward Drinker Cope in 1882.

Range

Fossil samples have been found in North America, Europe and Russia. In the United States, their fossil samples were found in Texas, New Mexico, West Virginia and Oklahoma. In Europe, fossil fragments have also been found in the Czech Republic and Germany.

Physical characteristics

Compared to its overall long and narrow build, Edaphosaurus had triangular shaped short head. It is believed that their deeper jaw had powerful muscles and the peg-like teeth along the side and front had serrated tips. They had a wide rib cage. Their foot was relatively shorter.

Like Dimetrodon, it also had a sail-like fin. The sail, stretching from neck to the lumbar region, was supported by bones of the vertebral column, but it was different in shape and morphology. Researchers suggested that there were several uses of the sail, such as protection against predator attacks, species recognition, sexual display, camouflage etc.

Discovery

Edward Drinker Cope described Edaphosaurus based on a left lower jaw and skull found from Texas. Cope classified it as a member of Pelycosauria and created the new family Edaphosauridae. He was unaware of the fact that Edaphosaurus had a large sail as the type specimen did not have any post-cranial skeleton except for an axis vertebra.

Interesting Facts

• In the British documentary film series ‘Walking with Monsters,’ Edaphosaurus was shown living in large groups, at times even hundreds, in which they nurtured their offspring.
• They were cold-blooded creatures. Scientists believe that they were active during the night.
• The Age of Reptiles, a mural by Austrian-Russian artist Rudolph Zallinger, depicts Edaphosaurus alongside Sphenacodon and Dimetrodon representing the Permian era at the Yale Peabody Museum.