Meat-Eating Missing Link Fossil Found In Africa
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By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - A new species of human ancestor, which looked like something halfway between the famed "Lucy" and true pre-humans, has been found in Ethiopia, scientists said Thursday.
More surprisingly, they found nearby evidence that the creature, named Australopithecus garhi, butchered and ate meat 2.5 million years ago.
The international team of researchers, led by Berhane Asfaw of Ethiopia's Rift Valley Research Service and Tim White of the University of California, Berkeley, scrabbled their specimen together from bits of bone and teeth found in the hard-baked rock of Ethiopia's Middle Awash region.
The area, a hard two-day drive northeast of Addis Ababa, is known for its fossil remains of pre-humans, known as hominids.
"The hardest part is to find the things because they are extremely rare and when you do find them they are almost never complete," White, whose findings are reported in the journal Science, said in a telephone interview.
The teeth and skull bits were encased in rock, which had to be chipped away.
But they found enough to place it halfway between Lucy's species, known as Australopithecus afarensis, and Homo habilis, a species of pre-human that lived about 2 million years ago.
"The new species is most like its ancestor afarensis," White said. "The face projects forward, the braincase is crested and small, but the premolars and molars are enormous. This combination of features has never been seen before, and that's why we named a new species."
The name comes from the word "surprise" in the local Afar language.
The team also found leg and arm bones from what may be the same species of creature in the same layer. These limbs look like something halfway between apes and humans, they said.
A. afarensis would have lived between 3.6 million and 2.9 million years ago. Lucy, the name given to one unusually complete skeleton, was about 3 feet (one meter) tall and weighed about 70 pounds (30 kg).
The A. garhi specimen, which White believes was a male, would have been four feet (1.2 meter) tall, if the leg and arm bones do belong to the same species.
It fills in a big gap in the spotty record of pre- humans.
"For this period, 2.5 million years ago, you know about things earlier and there are things you know about later, but for this period we know almost nothing,'' White said.
"You go into this period with, in essence, bipedal big- toothed chimps and come out with meat-eating large- brained hominids," he added in a statement. "That's a big change in a relatively short time. We'd really like to know more about what happened there."
A second report in Science indicates that these ape-men were butchering meat and feasting on nutritious bone marrow.
Near the Awash site, the late Jean de Heinzelin of the Royal Institute of the Natural Sciences in Brussels, Belgium, J. Desmond Clark of Berkeley and other colleagues found butchered antelope bones that had been cut with stone tools and cracked open.
"With the cut marks and breaking into the bones, that's really revolutionary stuff in hominids," White said.
"It shows conclusively what they were using those stone tools for. With the sharp stone tools they can get not only the meat but also the fat inside the bones."
While A. garhi cannot conclusively be linked with the butchered bones, they date to the same period and the pre-humans would be the best candidates for whoever cut up the animals, the researchers said.
White said it is not clear whether the animals were hunted or scavenged,
but he and other scientists believe that it was the ability to add meat
to the diet that allowed humans to spread and evolve.
Skull and Fossils Found in Ethiopia Prompt Missing-Link Debate
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By JOHN NOBLE WILFORD
New York Times, April 23, 1999
Digging beneath a sere plain in Ethiopia, paleontologists have found a skull and other fossils of what they say is a new prehuman species, possibly the long-sought connecting link between apelike ancestors and the human family.
Near the site, other scientists discovered the earliest known traces of stone tools used to butcher animals. Judging by cut marks on some ancient antelope bones, humanlike creatures gathering long ago beside a shallow lake used chipped stones to slice meat and other stones to crack leg bones to get at the nourishing marrow.
This probably was the work of members of the new species, the discoverers of both sites say; but, in any case, the butchered bones are strong evidence that the first toolmakers were able to feast increasingly on meat, which could have influenced the course of human evolution.
Both finds, which are being reported in Friday's issue of the journal Science, were dated to 2.5 million years ago, in the middle of a shadowy but pivotal period in human prehistory. The fossil record for hominids, human ancestors and their close kin, is frustratingly sparse between 3 million and about 2 million years ago. Yet this was the time when hominids took up toolmaking and evolved from the small-brained, apelike australopithecines into the first members of the Homo genus.
The discovery team, led by Berhane Asfaw, an anthropologist with the Rift Valley Research Services in Addis Ababa, Ethiopia, named the new species Australopithecus garhi (garhi means "surprise" in the language spoken by the Afar people in the region where the fossils were found).
"This species is descended from Australopithecus afarensis and is a candidate ancestor for early Homo," the scientists concluded.
Characteristics of the skull, teeth and limb bones seemed to mark the species as a descendant of A. afarensis, which lived from 3.7 million to 3 million years ago and are famously represented by the "Lucy" skeleton from Ethiopia. Even earlier species of australopithecines, found in Kenya, have been dated back to 4.2 million years. The hominids are thought to have split from the ape lineages more than 5 million years ago.
The A. garhi had a projecting apelike face and small braincase, similar to the Lucy species. But its teeth were much larger, which was what most surprised paleontologists about the fossils.
"This combination of features has never been seen before," said Tim White, a paleoanthropologist at the University of California at Berkeley and co-leader of the discovery team, "and that's why we named a new species."
Other skeletal remains at the site included leg and arm bones of what probably, but not certainly, was another member of the new species. From this evidence, scientists said, the individual was slightly less than 5 feet tall and had long legs and a human gait, but long, apelike forearms. It was more evidence of the species as a possible direct ancestor of the Homo genus.
As often happens in response to new discoveries in the contentious field of early human origins, other paleontologists differed in their interpretations of the findings. Bernard Wood of George Washington University in Washington said it was too soon to assess the place of the new fossils on the family tree.
In another Science article, Wood was quoted as saying, "At this point it's impossible to tell what's ancestral to what."
Ian Tattersall, a specialist in hominid fossils at the American Museum of Natural History in New York, said, "It probably is a new species, but it's difficult to say exactly where it fits into human evolution."
Alan Walker, a paleoanthropologist at Pennsylvania State University, said the fossils were an important start to filling in the million-year gap in knowledge of hominid evolution in East Africa.
To him, the new species "looks like an afarensis with big teeth," Walker said. "But it has a lot of primitive features, so if it is ancestral to Homo, a lot of evolution had to take place rather quickly" to arrive at the first Homo species around 2 million years ago. The transition to much larger brains began with Homo erectus, about 1.7 million years ago. Modern Homo sapiens are thought to have emerged less than 200,000 years ago.
Some other scientists questioned whether A. garhi was a better candidate as a Homo ancestor than A. africanus, a species that emerged about 2.8 million years ago and apparently lived mostly in South Africa. The place of africanus on the family tree has long vexed paleontologists.
Walker said one thing was clear: the new fossils were definitely not africanus specimens.
Although the butchered bones were found in sediment layers corresponding to the A. garhi fossils, White said, "We cannot yet conclusively link the new species with the butchery or the more modern limb proportions."
But the proximity of the cutmarked antelope bones to the hominid fossils is strong circumstantial evidence that these were the toolmakers and hearty meat eaters. Two years ago, paleontologists announced the discovery of 2.5 million-year-old stone tools elsewhere in Ethiopia, but missing was any clear associations with hominid fossils or animal butchering.
J. Desmond Clark, a University of California archeologist on the team, said there was "absolutely no shadow of a doubt" that the antelope bones were evidence of early stone-tool use. "You can clearly distinguish these cut marks from the kinds of marks left by carnivores," Clark said.
The archeologists were not surprised by the absence of any tools at the site. It is bereft of stone from which to make tools. Presumably, Clark said, the hominids had made their stone tools elsewhere and traveled with them as they visited good hunting places. This particular site, a desert now, was a grassy plain by a lake 2.5 million years ago and must have attracted prey for the hominids.
In any event, Clark said, the new findings indicate a "great cultural breakthrough" in which hominids gained the means to change their diet with more meat and the knowledge of the nutritional benefits of marrow. These were probably factors in subsequent increases in hominid brain sizes.
In their journal report, Clark's team wrote, "The combined evidence suggests that behavioral changes associated with lithic technology and enhanced carnivory may have been coincident with the emergence of the Homo clade from Australopithecus afarensis in eastern Africa."
Copyright 1999 The New York Times