Scientists Discover New Species of Human Ancestor

When American paleoanthropologist Lee R. Berger and his team of scientists from the University of Witwatersrand in Johannesburg, South Africa were first tipped off by a group of spelunkers that there was a previously inaccessible section of the local Rising Star Cave filled with bones, it’s doubtful that they could have predicted the gravity of the discovery that they were about to make. Now, two years later, Berger and a team of over 60 scientists from around the world have published a study revealing that their research has determined that the bones belong to a previously unknown ancestor of humanity, which they have dubbed homo naledi.

Within the Rising Star Cave, from which the new species takes its name (“naledi” is the local Sesotho language’s word for “star”), the team of researchers have so far identified over 1,550 fossil elements, making it the largest sample of any hominin species found at a single African site. Berger and his team have determined that the bones once belonged to at least 15 different individuals; according to the researchers, the naledi used the cave as a burial site where they would inter the bodies of their dead.

Burial Rituals

If Berger and his team’s hypothesis that the Rising Star Cave is an ancient tomb for an extinct pre-human species is correct, the discovery of homo naledi represents an overturning of previously held beliefs about the history of human ritual. Before now, it was believed that ritual burial was a behavior limited to modern humans, and not of any homo sapiens ancestor species.

While Berger estimates that h. naledi walked the earth near the beginning of the development of this homo genus, determining the fossils’ exact origin date has proven difficult, thanks to the mixing of sediment from different eras within the cave and a lack of fossilized fauna nearby. Given the new species’ primitive anatomy and small brain size, combined with geologists’ estimates that the cave is no more than three million years old, the researchers estimate that homo naledi likely walked the Earth between 2.5 and 2.8 million years ago.

Toolmakers

In addition to burying their dead, there is evidence that homo naledi also made and used tools, which helped justify the scientists classifying the new species as a member of the homo genus. The species also had a relatively modern structure to its feet, teeth, and jaws, and also walked upright on long legs, though it appears their average height was less than five feet tall. While some scientists, such as University of Pittsburgh Jeffrey H. Schwartz, are not yet convinced that the naledi should be considered a member of the homo genus (Schwartz says he feels that the fossils are closer to resembling Australopithecus, the pre-hominin genus of which the famous skeleton Lucy is the most well-known example), the authors of the study say they are confident in their classification.

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