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New human ancestor unveiled

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New human ancestor unveiled

A new species of hominid, Homo naledi, has been discovered in the single largest fossil hominid find in Africa. Shedding new light on the development of our own behaviour, it’s thought that this early ancestor practiced a form of burying its dead.
Wits University today (10 September 2015) announced the discovery of the new human relative, which appears to have intentionally deposited bodies of its dead in a remote cave chamber – a behaviour previously thought limited to humans.
The fossils were revealed for the first time during an international launch at the Maropeng Visitor’s Centre in the Cradle of Humankind World Heritage Site, attended by representatives from the South African government, participating researchers from all over the world, as well as local and international media.
It has been much anticipated since Professor Lee Berger, research professor in the Evolutionary Studies Institute at Wits, and a team of researchers, cavers and explorers announced in November 2013 that they had discovered a significant fossil find in a cave known as Rising Star in the Cradle of Humankind, some 50km northwest of Johannesburg.
They launched the Rising Star Expedition and have since then discovered more than 1 550 numbered fossil elements. The discovery is the single largest fossil hominin find yet made on the continent of Africa.
The fossiles, which have yet to be dated, lay in a chamber about 90m (some 100 yards) from the cave entrance, accessible only through a chute so narrow that a special team of very slender individuals was needed to retrieve them.
So far, the team has recovered parts of at least 15 individuals of the same species, a small fraction of the fossils believed to remain in the chamber. “With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage,” Berger says.
Perhaps most remarkably, the context of the find has led the researchers to conclude that this primitive-looking hominin may have practiced a form of behaviour previously thought to be unique to humans. The fossils – which consist of infants, children, adults and elderly individuals – were found in a room deep underground that the team named the Dinaledi Chamber, or “Chamber of Stars”.
That room has “always been isolated from other chambers and never been open directly to the surface,” says Dr Paul Dirks of James Cook University in Queensland, Australia, lead author of the eLife paper on the context of the find. “What’s important for people to understand is that the remains were found practically alone in this remote chamber in the absence of any other major fossil animals.”
So remote was the space that out of more than 1 550 fossil elements recovered, only about a dozen are not hominin, and these few pieces are isolated mouse and bird remains, meaning that the chamber attracted few accidental visitors. “Such a situation is unprecedented in the fossil hominin record,” Dirks says.
The team notes that the bones bear no marks of scavengers or carnivores or any other signs that non-hominin agents or natural processes, such as moving water, carried these individuals into the chamber.
“We explored every alternative scenario, including mass death, an unknown carnivore, water transport from another location, or accidental death in a death trap, among others,” said Berger.
“In examining every other option, we were left with intentional body disposal by Homo naledi as the most plausible scenario.”