Cienciaes.com: Dimetrodon, a reptile with a sail

2010-03-20 15:05:40

The first fossil remains of Dimetrodon were discovered in the United States by the American paleontologist Edward Drinker Cope in 1878. Dimetrodon was a pelycosaur reptile, closer to mammals than to modern reptiles, as evidenced by its teeth; In Dimetrodon, the different types of teeth characteristic of mammals had already begun to be differentiated: it had conical and pointed canines, with which it tore the meat of its prey, and other flat and very sharp teeth, which were used to cut the meat into pieces. smaller, which facilitated digestion. Its name means “teeth of two sizes.” Dimetrodon was a large predator, measuring three and a half meters in length and weighing more than two hundred kilos, which lived between 280 and 265 million years ago on the supercontinent of Pangea. Its most prominent feature was a large, bell-shaped dorsal sail, which rose from its neck to the tail-head. This sail was a layer of skin covered by numerous blood vessels and held in place by long spines that extended upwards from the spinal column, reaching a meter in height in the central part.

When the first vertebrates colonized the mainland, they encountered a problem: temperature control. The thermal inertia of water is much greater than that of air, so the temperature variations suffered by aquatic animals are much less. The first reptiles, cold-blooded animals, spent the nights torpid and took advantage of the heat of the sun to warm up and resume their activities. In the tropical region where Dimetrodon lived, the nights were cold and the days were hot. Dimetrodon, with its blood-vessel-filled sail exposed to the sun, heated up much faster than its prey. Thus, Dimetrodon could start hunting when its prey was not yet able to escape.