At the dawn of the Permian, tens of millions of years before the first dinosaurs, the synapsid Dimetrodon roamed the Earth. This 290 million-year-old animal was an apex predator in its time with powerful jaws and teeth to devour fish and tetrapods. Despite its appearance though, Dimetrodon was not a reptile. In fact, the synapsid is more closely related to modern mammals.

Dimetrodon is most easily identified by its iconic spine sail, a huge extension of its vertebrae that could grow over 5 feet tall. This sail's purpose could have ranged from courtship displays to temperature regulation, or even as a source of locomotion.

This specimen is a fossil fragment of a Dimetrodon neural spine sail. First featured in the Second Edition of the Mini Museum, we are excited to offer Dimetrodon as a single specimen at last. Our material comes from private lands in West Texas, USA. This region, known as the Texas Red Beds, contains one of the most complete fossil records of the Early Permian and dates to roughly, 280,000,000 years old.

These fragments of Dimetrodon neural spine sail material vary by size, color and shape. Each measures roughly 2 to 3 millimeters long. This ancient Permian era material is quite precious and it is rare to see in public hands.

Each fossil is enclosed in an acrylic specimen jar and ships in our classic 4 1/2" x 3 1/2", glass-topped riker box case. A small information card which serves as the certificate of authenticity is also included.

Also available are several larger segments of neural spine fossils and a complete showcase dorsal vertebra below.

"The apex of the spine in this species is slender, and apparently was flexible. The utility is difficult to imagine." ~ Edward Drinker Cope, 1886

The Permian Period represents a radical change to life in response to a more varied climate across the planet. In the oceans, we see the first true bony fish. On land, the evolution of amphibian life gives way to pure terrestrial animals, including Dimetrodon.

With a fearsome jaw and reptilian appearance, Dimetrodon is often mistaken for a dinosaur. However, this apex predator of the Early Permian Age is part of a major group of animals known as synapsids. In addition to reptile-like creatures such as Dimetrodon, Synapsids also includes all mammals... and yes, humans too!

Over the course of 20 million years, there were many species of Dimetrodon ranging in size and decked with a variety of iconic spine sail shapes. The purpose of this structure has been debated for many decades. Early theories centered on thermoregulation while more recent studies have shown that the spines lacked the necessary channels for carrying blood vessels.

In recent decades, the discussion has moved toward the sail's role in sexual dimorphism, but science is always testing new ideas and methods. As an example, a study in 2012 in conjunction with NASA's Jet Propulsion Laboratory suggests the sail may have served as a spring-like energy storage device for fast locomotion.

Dimetrodon was certainly not the only creature with such a spine sail. Take Spinosaurus, a dinosaur which emerged much later in the fossil record with little relation to Dimetrodon. Both animals sported the fashionable back sail due to convergent evolution, a process where two unrelated animals develop similar features and life styles.

Dimetrodon is one of the first terrestrial vertebrates to develop multiple types of teeth, including tightly compressed, recurved teeth with sharp cutting edges. Known as ziphodont teeth, scientists speculate this development was a result of a new, refined feeding style in which flesh is sheared from the bones by pulling instead of direct, bone-crushing force.

Note the graphic here for close study of this ziphodont edge: (a) Royal Ontario Museum (ROM) 1797 tooth, labial view, mesial carina to the right. (b) ROM 1797, scanning electron microscope (SEM) of posterior carina, apical up. (c) ROM 6039, SEM of posterior carina, basal up. (d) ROM 6039Z, posterior carina, apical left. Viewed under cross-polarized light with a lambda plate and oblique illumination. (e) ROM 6039K, anterior carina, apical left. Viewed under plain polarized light. c, crack; d, dentine; e, enamel; g, globular dentine; is, interdentinal sulcus; k, keel. Scale bars, (a) 0.5 cm, (b–e) 0.5 mm. (Source: Nature, Brink, Kirstin S., and Robert R. Reisz. "Hidden dental diversity in the oldest terrestrial apex predator Dimetrodon.")