Rare Permian Material! If all fossils are out of stock, sign up for email notifications as we do expect to get more over time.

With a fearsome jaw and reptilian appearance, Dimetrodon is often mistaken for a dinosaur. However, this family of Early Permian Age species falls into a disparate taxonomic clade known as Synapsids which includes Mammals. This specimen is a 0.92" fossil fragment of the Dimetrodon's iconic spine. The purpose of the spine sail is unknown, though speculation ranges from thermoregulation to sexual dimorphism, and perhaps even locomotion.