[In two papers published this week in the open-access journal eLife, the researchers said that the more than 1,550 fossil elements documenting the discovery constituted the largest sample for any hominin species in a single African site, and one of the largest anywhere in the world. Further, the scientists said, that sample is probably a small fraction of the fossils yet to be recovered from the chamber. So far the team has recovered parts of at least 15 individuals.]
A reconstruction of the skull and hand of Homo naledi, a human
ancestor discovered in
Acting on a tip from spelunkers two years ago, scientists in South Africadiscovered what the cavers had only dimly glimpsed through a crack in a limestone wall deep in the Rising Star cave: lots and lots of old bones.
The remains covered the earthen floor beyond the narrow opening. This was, the scientists concluded, a large, dark chamber for the dead of a previously unidentified species of the early human lineage — Homo naledi.
The new hominin species was announced on Thursday by an international team of more than 60 scientists led by Lee R. Berger, an American paleoanthropologist who is a professor of human evolution studies at the University of the
Witwatersrand in . The species name, H. naledi,
refers to the cave where the bones lay undisturbed for so long; “naledi” means
“star” in the local Sesotho language. Johannesburg
In two papers published this week in the open-access journal eLife, the researchers said that the more than 1,550 fossil elements documenting the discovery constituted the largest sample for any hominin species in a single African site, and one of the largest anywhere in the world. Further, the scientists said, that sample is probably a small fraction of the fossils yet to be recovered from the chamber. So far the team has recovered parts of at least 15 individuals.
“With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage,” Dr. Berger said.
Besides introducing a new member of the prehuman family, the discovery suggests that some early hominins intentionally deposited bodies of their dead in a remote and largely inaccessible cave chamber, a behavior previously considered limited to modern humans. Some of the scientists referred to the practice as a ritualized treatment of their dead, but by “ritual” they said they meant a deliberate and repeated practice, not necessarily a kind of religious rite.
“It’s very, very fascinating,” said Ian Tattersall, an authority on human evolution at the
of Natural History in American Museum , who was not involved in the research. “No
question there’s at least one new species here,” he added, “but there may be debate over
the Homo designation, though the species is quite different from
anything else we have seen.” New York
A colleague of Dr. Tattersall’s at the museum, Eric Delson, who also is a professor at
of the City University of New
York, was also impressed, saying, “Berger does it again!” Lehman College
Dr. Delson was referring to Dr. Berger’s previous headline discovery, published in 2010, also involving cave deposits at the Cradle of Humankind site, 30 miles northwest of
. He found many fewer fossils
that time, but enough to conclude he was looking at a new species, which he
named Australopithecus sediba.
Geologists said the individuals lived 1.78 million to 1.95 million years ago,
when australopithecines and early species of Homo were contemporaries. Johannesburg
Researchers analyzing the H. naledi fossils have not yet nailed down their age, which is difficult to measure because of the muddled chamber sediments and the absence of other fauna remains nearby. Some of its primitive anatomy, like a brain no larger than an average orange, Dr. Berger said, indicated that the species evolved near or at the root of the Homo genus, meaning it must be in excess of 2.5 million to 2.8 million years old. Geologists think the cave is no older than three million years.
The field work and two years of analysis for Dr. Berger’s latest discovery were supported by the University of the
Witwatersrand, the National Geographic
Society and the South African Department of Science and Technology/National
Research Foundation. In addition to the journal articles, the findings will be
featured in the October issue of National Geographic Magazine and in a two-hour NOVA/National Geographicdocumentary to air Wednesday on PBS.
Scientists on the discovery team and those not involved in the research noted the mosaic of contrasting anatomical features, including more modern-looking jaws and teeth and feet, that warrant the hominin’s placement as a species in the genus Homo, not Australopithecus, the genus that includes the famous Lucy species that lived 3.2 million years ago. The hands of the newly discovered specimens reminded some scientists of the earliest previously identified specimens of Homo habilis, who were apparently among the first toolmakers.
At a news conference on Wednesday, John Hawks of the
, Madison, a senior author of
the paper describing the new species, said it was “unlike any other species
seen before,” noting that a small skull with a brain one-third the size of
modern human braincases was perched atop a very slender body. An average H.
naledi was about five feet tall and weighed almost 100 pounds, he said. University of Wisconsin
Tracy Kivell of the
, in University of Kent , an associate of Dr. Berger’s
team, was struck by H. naledi’s “extremely curved fingers, more curved than
almost any other species of early hominin, which clearly demonstrates climbing
William Harcourt-Smith of
of the City University of New
York, a researcher at the Lehman College of Natural History, led the
analysis of the feet of the new species, which he said are “virtually
indistinguishable from those of modern humans.” These feet, combined with its
long legs, suggest that H. naledi was well suited for upright long-distance
walking, Dr. Harcourt-Smith said. American Museum
In an accompanying commentary in the journal, Chris Stringer, a paleoanthropologist at the
in Natural History Museum , found overall similarities
between the new species and fossils from Dmanisi, in the
former Soviet London , dated to about 1.8 million
years ago. The Georgian specimens are usually assigned to an early variety of
Homo erectus. republic of Georgia