Science

New Hominid Species Discovered in South Africa

Benedicte Kurzen for The New York Times

Lee R. Berger, an American paleoanthropologist, with son Matthew and dog Tau, at the at the Malapa site where they discovered the new hominid species.

CRADLE OF HUMANKIND, South Africa — Nine-year-old Matthew Berger dashed after his dog, Tau, into the high grass here one sunny morning, tripped over a log and stumbled onto a major archaeological discovery. Scientists announced Thursday that he had found the bones of a new hominid species that lived almost two million years ago during the fateful, still mysterious period spanning the emergence of the human family.

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Benedicte Kurzen for The New York Times

The cranium of Australopithecus sediba from the Malapa site in South Africa.

“Dad, I found a fossil!” Matthew said he cried out to his father, Lee R. Berger, an American paleoanthropologist, who had been searching for hominid bones just a hill and a half away for almost two decades. Fossil hunters have profitably scoured these rolling grasslands north of Johannesburg since the 1930s.

Matthew held the ancient remains of a 4-foot-2 boy who had been just a few years older than Matthew himself. Dr. Berger, with the Institute for Human Evolution at the University of the Witwatersrand in Johannesburg, and his fellow researchers have since found much more of the boy’s skeleton, including his extraordinarily well-preserved skull, and three other individuals. South Africa’s children will compete to name the boy.

In a report being published Friday in the journal Science, Dr. Berger, 44, and a team of scientists said the fossils from the boy and a woman were a surprising and distinctive mixture of primitive and advanced anatomy and thus qualified as a new species of hominid, the ancestors and other close relatives of humans. It has been named Australopithecus sediba.

The species sediba, which means fountain or wellspring in Sotho, strode upright on long legs, with human-shaped hips and pelvis, but still climbed through trees on apelike arms. It had the small teeth and more modern face of Homo, the genus that includes modern humans, but the relatively primitive feet and “tiny brain” of Australopithecus, Dr. Berger said.

Geologists estimated that the individuals lived 1.78 million to 1.95 million years ago, probably closer to the older date, when australopithecines and early species of Homo were contemporaries.

Dr. Berger’s team said that the new species probably descended from Australopithecus africanus. At a teleconference on Wednesday, he described the species as a possible ancestor of Homo erectus, an immediate predecessor to Homo sapiens, or a close “side branch” that did not lead to modern humans.

Scientists not involved in the research are debating whether the bones belong to the Homo or Australopithecus genus, but most agree that the discovery of the skeletons at the Malapa site here in the Cradle of Humankind, a World Heritage site where dolomitic limestone caves contain fossils of ancient animals and hominids, is a major advance in the early fossil history of hominids.

“They are a fascinating mosaic of features,” said Rick Potts, director of the Human Origins Program at the Smithsonian. “It reminds us of the combining and recombining of characteristics, the tinkering and experimentation, that go on in evolution.”

Dr. Berger said the path to the discovery began over the Christmas holidays in 2007 when he began using Google Earth to map caves in the Cradle of Humankind. On a recent visit to his office, he rotated Google Earth images of the dun landscape on his desktop, showing how he spotted the shadows and distortions of the earth that gave clues to the location of caves, often topped with wild olive and white stinkwood trees.

On Aug. 15, 2008, when Matthew called his father to look at the bones he had found, Dr. Berger began cursing wildly as he neared his son. The boy mistook his father’s profanity for anger. But from 15 feet, Dr. Berger, who had done his Ph.D. thesis on hominid shoulder bones, among them the clavicle, was astounded to see that his son had in his hands a clavicle with the unmistakable shape of a hominid.

“I couldn’t believe it,” Dr. Berger giddily recalled. “I took the rock, and I turned it” and “sticking out of the back of the rock was a mandible with a tooth, a canine, sticking out. And I almost died,” he said, adding, “What are the odds?”

In March 2009 he found the remarkably intact cranium of the sediba boy whose clavicle Matthew had picked up. Donald C. Johanson, who found the famed 3.2-million-year-old Lucy skeleton in Ethiopia in 1973, described the skull as “a fabulous specimen.”

In his lab last week, Dr. Berger took a fire-resistant case from a safe and reverently lifted the skull from its foam bed, revealing its startlingly delicate face.

“Beautiful, isn’t it?” he said.

The scientists also found a profusion of animal fossils at the site — saber-toothed cats, mongooses, wild dogs, antelopes and hyenas, among others. Dr. Berger and Paul Dirks, a geologist at James Cook University in Queensland, Australia, hypothesized that the animals might have been lured to the edge of a 100- to 150-foot funnel-shaped shaft into a deep cave, perhaps by the scent of water during a drought, then plunged to their deaths.

Celia W. Dugger reported from Cradle of Humankind, and John Noble Wilford from New York.

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