Edaphosaurus (/ˌɛdəfoʊˈsɔːrəs/, meaning "pavement lizard" for dense clusters of teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago,[1] during the Late Carboniferous to Early Permian.

Back parts of the roof of the mouth and the inside of the lower jaw held dense batteries of peglike teeth, forming a broad crushing and grinding surface on each side above and below.

However, paleontologists now think that Edaphosaurus ate plants, although tooth-on-tooth wear between its upper and lower tooth plates indicates only "limited processing of food"[7] compared to other early plant-eaters such as Diadectes, a large nonamniote reptiliomorph (Diadectidae) that lived at the same time.

The recently described Melanedaphodon from the Middle Pennsylvanian subperiod of the Carboniferous Period in North America is currently the earliest known edaphosaurid and represents a transitional stage from a diet of hard-shelled invertebrates such as insects and mollusks to fibrous plants.

Melanedaphodon had large and bulbous teeth along its upper and lower jaws, but also had "a moderately-developed tooth battery" on its palate, "which appears intermediary towards the condition seen in Edaphosaurus" and would have helped process tough plant material.

The height of the sail, curvature of the spines, and shape of the crossbars are distinct in each of the described species of Edaphosaurus and show a trend for larger and more elaborate (but fewer) projecting processes over time.

[9] Bennett argued that the bony projections on Edaphosaurus spines were exposed and could create air turbulence for more efficient cooling over the surface of the sail to regulate body temperature.

[10] Recent research that examined the microscopic bone structure of the tall neural spines in edaphosaurids has raised doubts about a thermoregulatory role for the sail and suggests that a display function is more plausible.

[16] In 1907, American paleontologist Ermine Cowles Case suggested that the skull of Edaphosaurus might belong with skeletons called Naosaurus, based on a specimen found in 1906 that appeared to associate elements of both.

[17] In 1913, Samuel Wendell Williston and Case described the new species Edaphosaurus novomexicanus from a fairly complete specimen unearthed in New Mexico in 1910, in which a sailbacked Naosaurus-type skeleton was found with a small Edaphosaurus-type skull.

The nominal species Naosaurus raymondi was assigned to Edaphosaurus by Romer and Price (1940), but Modesto and Reisz (1990) designated it a nomen vanum,[21] and Spindler (2015) considered it probably referable to Ianthasaurus due to its age and stratigraphy.

[14] The strange appearance of Edaphosaurus with its distinctive dorsal sail composed of tall spines studded with bony knobs has made it a popular subject for scientific reconstructions and paleoart in museums and in books.

Spiny-backed reconstructions of "Naosaurus" (with a large carnivore's head) appeared in different German sources, including as a tile mosaic on the façade of the Aquarium Berlin in 1913 (destroyed in World War II and later recreated).

[26] The main part of the "Naosaurus" skeleton was a set of dorsal vertebrae with high spines (AMNH 4015) from a partial Edaphosaurus pogonias specimen found by the fossil collector Charles H. Sternberg in Hog Creek, Texas in 1896.

Because of the still incomplete knowledge of Edaphosaurus at the time, the rest of the mount was a "conjectural" composite of various real fossil bones collected in different places with other parts recreated in plaster, including a skull (AMNH 4081) based on Dimetrodon (per E.D.

His reconstruction of Edaphosaurus cruciger, as shown in a drawing, had a much smaller head (with teeth for crushing mollusks or plants), more robust limbs, and a somewhat longer tail than Osborn's carnivorous "Naosaurus" mount.

[33] Knight's 1930 depiction of Edaphosaurus, apart from its shortened tail, was much more accurate than his earlier images of "Naosaurus" for the American Museum of Natural History, incorporating a small head and a curved profile to the sail spines.

Artist Rudolph Zallinger depicted Edaphosaurus in a more scientifically updated form (with a long tail) alongside Dimetrodon and Sphenacodon to represent the Permian period in his famous The Age of Reptiles mural (1943-1947) at the Yale Peabody Museum.

The September 7, 1953 issue of Life presented The Age of Reptiles in reverse image (earliest to latest, left to right) of the mural order as a double-sided foldout page in which Edaphosaurus appeared in an Early Permian landscape[35] with plants and animals of the period.

(The choice to portray Edaphosaurus was based in part on edaphosaurid fossils found in native Carboniferous rocks in what is now the Czech Republic, originally identified as "Naosaurus" and now called Bohemiclavulus.)

These images appeared in the series of popular general audience books on prehistoric animals that Burian produced in collaboration with Czech paleontologists Josef Augusta and Zdeněk Špinar beginning in the 1930s and on into the 1970s.