Antetonitrus (pronounced ant-EE-tohn-IET-rus; meaning "before the thunder") is the oldest known genus of sauropod dinosaur, living during the Late Triassic Period of southern Africa. It was a quadrupedal herbivore, like many of its later relatives, although it was far smaller than some of them. Antetonitrus was the largest animal in its environment, reaching up to 33 feet (10 m) long and weighing up to two tons, but still shows some primitive adaptations to use the forelimbs for grasping, instead of purely for weight support.