Plateaosaurus means flat lizard. It is the first giant among dinosaurs and the largest of its era. It is also the first in the lineage of giant dinosaurs such as Diplodocus. It is recognized by its long neck, imposing body, and its powerful legs. A quadruped, it is able to stand on its two hind legs to run faster as well as to reach food at greater heights. Its front legs were also equipped with sharp claws to more easily grab branches and bring them to itself. They were also used for defense against predators. Its flat teeth allowed it to crush all types of plants. Its stomach contained stones, called gastroliths, used to grind food.