WHAT’S THE STORY?

A HUGE trove of bones found deep in a cave near Johannesburg, in South Africa, could be the remains of a new species of ancient human, according to scientists.

They have named the creature Homo naledi (naledi means “star” in the local language, Sesotho) and say it appears very primitive in some respects, yet remarkably like modern humans in others. Its brain is tiny, its teeth small and simple. The thorax is ape-like as are its shoulders, but its hands are more modern, their shape well suited to making basic tools.

Its feet and ankles are built for walking upright, but its fingers are curved, a feature that is often seen in apes, which spend much of their time in the trees.

The find – in an area once known as the Cradle of Humankind because so many fossils of our early ancestors were found there – has been described as one of the greatest fossil discoveries of the past 50 years. Researchers say the discovery of 15 partial skeletons in the Rising Star cave, which is the largest single find of its type in Africa, will change ideas about our human ancestors.

Professor Lee Berger, the paleoanthropologist who led the work at the University of Witwatersrand, in Johannesburg, said: “We’ve found a new species that we are placing in the genus Homo, which is really quite remarkable.”

His description of the slender, small-brained creatures was less than complimentary: “long-legged”, “pinheaded” and “gangly”. The males were about 5ft tall, with females a little shorter.

WHO FOUND THE BONES?

THE story starts two years ago when recreational cavers Steven Tucker and Rick Hunter entered the cave, 30 miles north-west of Johannesburg. They knew that a scientist in Johannesburg was looking for bones, so they took a less trodden path.

The men worked their way through a tight constriction, climbed a jagged wall and found themselves in a cavity decorated with stalactites. As Hunter began shooting video, Tucker found a fissure in the cave floor that led to a narrow, vertical chute less than 8ins wide in some parts.


Both men are slender, built of wiry muscle and bone, and had they been just a little bigger they would not have been able to fit in the chute to find the bones.

A team of lightly built female researchers had to be brought in to excavate the bones. The women recovered more than 1,500 pieces of bone belonging to at least 15 individuals – ranging from infants to juveniles and one very old adult.

There are still thousands more pieces of bone in the chamber but, because they were not encased in rock, Berger’s team has not been able to date them.

THE MISSING LINK?

BERGER wanted to find fossils that could shed light on the biggest mystery in human evolution, the origin of our genus, Homo, between two and three million years ago.

On one side there are the ape-like australopithecines and the famous example, Lucy, discovered in Ethiopia in 1974.

On the other is Homo erectus, the tool-wielding, fire-making, globe-trotting species with a big brain and body proportions like ours.

The term “missing link” is not one favoured by those in the field, but Berger said naledi could be thought of as a “bridge” between more primitive bipedal primates and humans, so a “sort of” missing link.


He said: “We’d gone in with the idea of recovering one fossil. That turned into multiple fossils. That turned into the discovery of multiple skeletons and multiple individuals.

“And so, by the end of that remarkable, 21-day experience, we had discovered the largest assemblage of fossil human relatives ever discovered in the history of the continent of Africa. That was an extraordinary experience.”

Professor Chris Stringer, of the Natural History Museum, said: “What we are seeing is more and more species of creatures that suggests that nature was experimenting with how to evolve humans, thus giving rise to several different types of human-like creatures originating in parallel in different parts of Africa. Only one line eventually survived to give rise to us.”

However, Christoph Zollikofer, an anthropologist at the University of Zurich, said many of the bone characteristics used to claim naledi as a new species were seen in more primitive animals, and by definition could not be used to define a new species.

He said: “The few ‘unique’ features that potentially define the new species need further scrutiny, as they may represent individual variation, or variation at the population level.”

Tim White, a paleoanthropologist at the University of California, said: “From what is presented here, they belong to a primitive Homo erectus, a species named in the 1800s.”

Berger believes the discovery of a creature with such a mix of modern and primitive features should make scientists rethink the definition of what it is to be human – so much so that he himself is reluctant to describe naledi as human.

The team’s findings have been published in the online journal Elife.