Why one famous predator shrank two ways: Fossils reveal distinct growth strategies in early Permian Dimetrodon

The sail-backed predator Dimetrodon is one of the most iconic animals of the early Permian—long before dinosaurs dominated Earth. Most known species of this early relative of mammals reached large body sizes, sometimes up to 3 meters (10 feet) in length and 250 kilograms (550 pounds). Yet some species remained surprisingly small. A new study by an international research team led by Dr. Aurore Canoville of the Friedenstein Stiftung Gotha and the Museum für Naturkunde Berlin now shows that these small body sizes were achieved through very different growth strategies.