By Minassie Teshome

ADDIS ABABA, Ethiopia- Scientists have discovered 4.1 million year-old fossils in northeastern Ethiopia, a monumental discovery said to fill a missing gap in human evolution.

The fossils represent unambiguous evidence for human evolution, a press release from the group responsible for the find, the Middle Awash paleo-anthropological research project, stated.

This new discovery links the earlier Ardipithecus ramidus species and the later Australopithecus afarensis, the species that the famous ‘Lucy’ discovery, found in Ethiopia in 1974, belongs to.

Dr. Birhane Asffaw, one of the project researchers, told SSI that, “There are so many gaps in between in human evolution. What we are trying to do is to fill all the gaps. What we have is windows of the past because there is not a continuous record of human evolution.”

Found in the Afar region, about 230 kilometers northeast of Addis Ababa, the fossils have the most continuous record of human evolution, according to the researchers, with a depth of sediments of about one kilometer.

Dr. Birhane said that the species of the new discovery was called Australopithecus anmensis, which was found in Kenya for the first time in 1995.

“Our present discovery was found ten years ago in Kenya, but we were not sure at that time, for it was a single fossil; only the upper jaw of human,” Dr. Birhane said, and added that there was some indication that it was younger than the older fossils, though they were not exactly sure how much younger.

Though the age of the Kenya fossils was not fully determined, researchers continued the research with the assurance of understanding it was younger than the oldest Ardipithecus ramidus, which was 4.4 million years old.

“In 2000, when the work continued, we went back to the field. We were planning to work in the older sediment area, and our camp was across the river, but when we tried to cross the river we were stopped by a big flood that came from the highlands of Ethiopia,” Dr. Birhane recalls.

They had to switch and change their direction that particular day, and started working on the south side of the river, containing younger sediment, where these new hominids were just found.

The fossils accumulated between 1995-2006 are from around 30 different human body parts and represent eight individuals.

These specimens include the largest hominid canine found so far, the earliest known thigh bone of the species, and hand and foot bones.

Dr. Birhane said the new discovery has some features in common with the earlier fossils, from 4.4 million years ago, and with the Lucy discovery, found in the same area and dating 3.4 millions old.

“We can say it is a link, connecting the earlier chapter…of evolution from six to about 4.4 million years, and the other chapter of human evolution, and chronologically it is younger than the former and older than latter.”

All the discovered fossils are now in Ethiopia and were shown to the members of the media during a press conference this week.

According to the researchers, these new fossils are of major significance to the country and should be looked upon as a national treasure and a symbol of civilization.

Dr. Berhane said, “We [Ethiopians] are lucky because we are the custodians of the historical record of all human kind.”

It also means that the largest concentration of fossils is found in the east African Rift-Valley, from Ethiopian to Tanzania.

“Though some researchers have found fossils out of the valley, for example in Chad, those areas have little concentration of fossils. This may possibly suggest the origin of human kind in this corridor of the rift and is, I think, specifically in the Afar region, because of the density of the fossils,” Berhane added.

“We now know where Australopithecus came from before 4 million years ago,” said Professor Tim White, who was among the researches to publish the discovery in the journal Nature.

The hominid had a small brain, big teeth and walked on two legs.

“It is fair to say that some species of Ardipithecus gave rise to Australopithecus,” Professor White added.

The finding also extends the range of Au. anamensis in Ethiopia.

Professor White says the large teeth suggest the hominid was able to eat fibrous foods and roots, compared with earlier species of Ardipithecus that had smaller teeth, which restricted their diet.

Along with the hominid fossils, the scientists discovered hundreds of remains of pigs, birds, rodents and monkeys, as well as hyenas and big cats, which gave them an idea of the habitat in which the ancient humans existed.

“Here, in a single Ethiopian valley, we have nearly a mile-thick stack of superimposed sediments and twelve horizons yielding hominid fossils,” Professor White said.

The fossils were found and analyzed by scientists from the United States, Ethiopia, Japan and France, and were unearthed in the Middle Awash area in the Afar desert of eastern Ethiopia.

“These discoveries confirm the Middle Awash study area as the world’s best window on human evolution,” said Professor White.

The Sub-Saharan Informer

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