A huge haul of bones found in a small, dark chamber at the back of a cave in South Africa may be the remnants of a new species of ancient human relative.
Explorers discovered the bones after squeezing through a fissure high in the rear wall of the Rising Star cave, 50km from Johannesburg, before descending down a long, narrow chute to the chamber floor 40 metres beneath the surface.
The entrance chute into the Dinaledi chamber is so tight - a mere eight inches wide - that six lightly built female researchers were brought in to excavate the bones. Footage from their cameras was beamed along 3.5km of optic cable to a command centre above ground as they worked inside the cramped enclosure.
The excavators recovered more than 1,500 pieces of bone belonging to at least 15 individuals. The remains appear to be infants, juveniles and one very old adult. Thousands more pieces of bone are still in the chamber, smothered in the soft dirt that covers the ground.
The leaders of the National Geographic-funded project believe the bones - as yet undated - represent a new species of ancient human relative. They have named the creature Homo naledi, where naledi means "star" in Sesotho, one of the official languages of South Africa, and the primary official language of Lesotho. But other experts on human origins say the claim is unjustified, at least on the evidence gathered so far. The bones, they argue, look strikingly similar to those of early Homo erectus, a forerunner of modern humans who wandered southern Africa 1.5m years ago.
"We've found a new species that we are placing in the genus Homo, which is really quite remarkable," said Lee Berger, a paleoanthropologist who led the work at the University of Witwatersrand in Johannesburg. He described the slender, small-brained creatures as "long-legged", "pinheaded" and "gangly". The males stood about 5ft, with females a little shorter.
Measurements of the bones show that the creature has a curious blend of ancient ape and modern human-like features. Its brain is tiny, the size of a gorilla's. Its teeth are small and simple. The thorax is primitive and ape-like, but its hands more modern, their shape well-suited to making basic tools. The feet and ankles are built for walking upright, but its fingers are curved, a feature seen in apes that spend much of their time in the trees. The findings are reported in two papers published in the online journal eLife.
