Mary Leakey was the first person to find this type of species in 1959. Most of these remains have been found spread over East Africa(1). The Australopithecus robustus and the Australopithecus boisei are very similar to each other and are thought to have descended from the Australopithecus aethiopicus. Other scientists believe that the Australopithecus robustus evolved from Australopithecus africanus instead(2). The distinct characteristics of this species are its very large teeth as well as its thickened skull. This find was very important in the history of paleontology for it cleared up many questions on Milford Wilpoff's hypothesis called the "Single Species Hypothesis". This idea states that every niche in nature can only support one species. When more than one species occupies a specific niche competition arises until one species completely overpowers the other(3). Wilpoff believed that if different hominids came into contact with each other in the wild they would naturally start to act like each other; therefore, not be able to occupy the same niche. The results of this situation would vary where either one of the species would be overpowered, or new species would not be able to evolve due to the competition. In response to this hypothesis it was believed that single sexual dimorphism occurred, with Australopithecus robustus being the male sex and Australopithecus africanus being the female sex. When both a male and female Australopithecus boisei were discovered from the same location in the same time period it proved that it was a separate species and put Wilpoff's hypothesis into question(1). One distinct difference that set the Australopithecus boisei apart from previous species was its massive jaws. The teeth in the back were very large as compared to its front canines, which were quite small. The surfaces of these back teeth were also very worn, which gave clues that this species ate coarse food and used these large back teeth to grind. With such large jaws one would think that the jaw region would protrude, but actually it was tucked in. This formation provided a very powerful vertical bite(3) not seen before.

Australopithecus robustus