During the Middle Triassic era, shortly before the first dinosaurs appeared on Earth, a small reptile appeared on the territory of present-day Argentina, called Lagosuchus.
Lagosuchus was rather light and had long, thin hind limbs that allowed him to run very fast. Some scientists even believe that he could jump in the manner of a rabbit or a kangaroo. Speed and mobility were the only defense of the Lagosuch from the large carnivorous reptiles that lived next to it in the desert on the territory of modern South America.
Like the first dinosaurs, Lagosuchus moved only on its hind legs. In fact, Lagosuchus and its close relatives Marasuchus (Mara Crocodile) and Lagerpedon (Rabbit Snake) were the very first known bipedal animals. The appearance of bipedal animals was a huge event in evolution, because until the Middle Triassic, all animals moved only on four limbs.
Walking on two legs allowed the forelimbs to be released, which made running more efficient and made it possible to catch prey with the help of the forelimbs. Lagosuch had a long tail, which was a counterbalance to a thin, graceful neck. The body of the animal was short and compact.
Lagosuchs ate meat, so their jaws contained a number of small sharp teeth. The front paws were long and ended in a three-toed hand. The sharp claws of the animal allowed it to catch and hold prey, such as insects or small vertebrates.
Lagozuhi, Mazhzukhi and Lagerdions are the closest relatives of dinosaurs. Studying their fossilized remains allows scientists to better understand the origin and evolution of dinosaurs. Since the fossil remains of Lagosuchus and the most ancient dinosaurs were found in the same area, this made it possible for scientists to assume that dinosaurs descended from animals similar to Lagosuchus.