Edaspids

Edaspids, commonly referred to as edaphosaurids, are a family of extinct synapsids that lived from the Late Carboniferous into the Early Permian periods, roughly 300 to 270 million years ago. They are part of the early, sail-backed, pelycosaur-grade synapsids and include the best-known genus Edaphosaurus. The term edaspid is not widely used in current taxonomy; the accepted name is Edaphosauridae.

Anatomy and appearance: Edaphosaurids are notable for a large sail running along the back, formed by elongated neural spines. They possessed relatively broad skulls with teeth adapted for processing plant material, indicating a herbivorous or omnivorous diet. Limbs and posture suggest a sprawling to semi-erect gait in life.

Ecology and significance: The sail may have played a role in thermoregulation, display, or social signaling. Their herbivorous habit represents an early experimentation with plant-eating among synapsids, a contrast to many contemporaries that were carnivorous.

Distribution and fossil record: Fossils of edaphosaurids have been found in North America and Europe, with the best-known material from Late Carboniferous to Early Permian deposits. They provide important data on early synapsid diversification and the evolution of sail-backed forms before the rise of therapsids.