Edaphosaurus (Gabriel Ugueto)

First image is a excellent illustration by the very talented artist Gabriel Ugueto. Long ago on a foggy morning during the Early Permian Period, a pair of Edaphosaurus cruciger are slowly waking up to the sun's rise. Easily one of the more recognizable edaphosaurid synapsids, ‬despite that this genus is often presented in the shadow cast by the much more famous Dimetrodon. Edaphosaurus was first named and described by Edward Drinker Cope in 1882, Edaphosaurus pogonias (type species). With E. pogonias included fives species are currently accepted, the other four are; E. cruciger (Cope, 1878) although Cope originally described it as a species of Dimetrodon, E. novomexicanus (Williston and Case, 1913), E. boanerges (Romer and Price, 1940), and E. colohistion (Berman, 1979). Edaphosaurus means "pavement lizard", derived from Greek edaphos ("ground"; also "pavement") and sauros ("lizard"). The naming is due to Edaphosaurus's dense clusters of teeth on both the upper and lower jaws. Now because of the other meanings for the Greek word edaphos, such as "soil, earth, ground, land, and base", it is often inaccurately translated as "earth lizard", "ground lizard", or "foundation lizard". The type species name pogonias (Greek) means "bearded", which refers to the enlarged inward sloping chin on the lower jaw. 

 Classified as Animalia, Chordata, Synapsida, Sphenacomorpha, and Edaphosauridae. Fossil remains of Edaphosaurus have been found in West Virginia, Ohio, Oklahoma, New Mexico, and originally Texas, USA. A few fragmentary remains that have been attributed to Edaphosaurus have been discovered in eastern Germany (central Europe) as well. It lived during the Late Carboniferous to Early Permian Periods, from the Pennsylvanian to Cisuralian Epochs (Gzhelian to Kungurian Ages 303.4 - 272.5 MYA). Depending on the species Edaphosaurus could reach 0.5 to 3.5 meters (1.6 to 11.5 feet) long and weigh over 300 kilograms (660 lbs). With Edaphosaurus cruciger being the largest species in size. The skull of Edaphosaurus is surprisingly small when compared to the size of the body, but unlike it's relative Dimetrodon, Edaphosaurus was at the opposite end being a herbivore specialising in low growing vegetation. They would have had a capacious gut, along with symbiotic bacteria to aid in breaking down cellulose and other indigestible plant material. The sail that is on their backs are near impossible not to talk about, it was basically a growth of thin tissue,‭ ‬perhaps only skin thin,‭ ‬supported by elongated neural spines. 

 They were shorter than the sail of Dimetrodon, but were heavier, and bear numerous small crossbars. Edaphosaurus along with it's close relatives evolved their tall dorsal sails independently of other sail-back animals, like members of the Sphenacodontidae family such as Dimetrodon and Secodontosaurus that lived at the same time, an unusual example of parallel evolution. The function for their sail is debated, one popular theory is thermoregulation that in lay terms means control of body temperature. This is not accepted by all however, studies done on these tall neural spines have now put doubt on this theory. Plausibly the sail for Edaphosaurus was used for display, this would include Edaphosaurus being able to recognize other individual‭ ‬Edaphosaurus from other genera sail-backed members of Eupelycosauria, Dimetrodon‭ for example. They could possibly recognize ‬different species of their own genus‭ (‬each species having its own pattern/color set‭)‬,‭ ‬and even signalling to attract a mate. It could also be possible that the sail may have grown more intense at certain times of the year‭, like the approach of the breeding season‭. Ultimately the precise function of the sail is still open for debate,‭ it could have fulfilled more than just one purpose. Within popular culture Edaphosaurus appeared in a 2005 three-part nature documentary television miniseries titled Walking with Monsters: Life Before Dinosaurs. Second image is a skeletal mount of Edaphosaurus pogonias, displayed at the Field Museum of Natural History, located in Chicago, Illinois, United States.