Paleontologist Adam Yates from the University of the Witwatersrand presented an incomplete skeleton of the Aardonyx celestae at a news conference Wednesday.
The findings of Yates and his team have been published in the Royal Society journal Proceedings B.
The species was a plant-eater dating back about 200 million years to the early Jurassic period. The dinosaur walked on its hind legs but could drop to all fours and stood nearly 6 feet (about 1.7 meters) high at the hip.
Yates believes it represents a missing evolutionary link between earlier dinosaurs and their descendants.