"Being that we have very complete specimens of different sexes, derived from a single moment in time, we have an opportunity to explore questions that relate both to ancestral forms, as well as to potentially descendant species," added Berger, a senior research officer and director of the School of Geosciences at the University of Witwatersrand.
He and his team made the discovery after investigating caves at several locations in South Africa. The nine-year-old son of one of Berger's post-doctoral students, Job Kibii, found the partial skeleton of a 60-pound, nine- to 13-year-old male hominid at what is known as the Malapa site.
Further exploration led to the discovery of the remains for an adult female in her late twenties or early thirties weighing around 73 pounds. Both she and the excavated young male were identified as being members of the new Australopithecus species, with sediba meaning "wellspring."
Since the fossils for at least 25 animals, including saber-toothed cats, a wildcat, a brown hyena, a wild dog, antelopes, and a horse, were also found in the cave, the researchers believe the deep site acted like a "death trap" for individuals seeking water. The now fossilized woman and boy appear to have "taken a significant fall" before plunging, or being later washed by rainwater, around 164 feet. Their bodies were then buried by a roof cave-in.