Meet our newest ancestor: Homo Naledi

On 10 September, scientists announced what just may be the single most important pre-historic find in the last half century. South Africa has long been a region where uncovered ancient remains have yielded an enormous amount of data about our species, Homo Sapiens', evolutionary roots.

Now, in the Rising Star Caves 50km north of Johannesburg, the discovery of 1550 bones from 15 individuals shakes up everything we thought we knew about how modern humans became, well, human.

Meet Homo Naledi

Naledi means "star" in Sesotho (one of South Africa's official languages and Lesotho's primary language). And, though H. naledi shares our genus, Homo, it is classified as a hominin, an extinct human species that lived over 100,000 years ago.

Paleoanthropologists say that, while H. naledi has yet to be dated, its fossils reflect an "anatomical mosaic," a surprising mix of a gorilla-sized brain and distinctly human-like feet and ankles.

Lee Berger, the scientist from the University of Witwatersand who led the excavation team, suspects H. naledi wasn't just a structural pre-cursor to humans but had also developed a sophisticated ritual of disposing their dead. This hypothesis is based on where the first traces of H. naledi were found, in a remote and largely inaccessible chamber 30 metres below the ground.

To reach the site, researchers had to crawl through a narrow chute eight inches wide. Berger claimed the extreme isolation of H. naledi fossils implied they must've gone down into the subterranean depths with some purpose in mind, which would also have required torches to navigate. The only other archaic humans to display such cultural complexity are Neanderthals and Homo erectus, humanity's two most recent ancestors.

If true, this proposal points to an entirely original paradigm for viewing our distant past as H. naledi was an animal (not yet human) that had, in Berger's words, the "cognitive ability to recognise its separation from nature".

Other experts, however, have dismissed the possibility outright. Some, such as William Jungers at the Stony Brook School of Medicine in New York, have urged caution in over-hyping H. naledi. Until the fossils have been properly dated, Jungers argued ".they are more novelties than game-changers".

Wherever the truth may lie, one thing is for certain: Berger's breakthrough highlights how much we actually don't understand about our early origins and how much waits to be discovered, out there in the bottom of a cave pit where no one has gone before.