A team of scientists from Arizona State University has found the earliest evidence of our human genus during a field research in Ethiopia, back in 2013.

The fossil is nothing more than the left side of a jaw with five teeth. It is 2.8 million years old and predates the similar fossils from the human genus – Homo – with more than 400 thousand years.

The discovery has been made public today, March 4, in the journal Science. Even though in the past scientists have discovered even older fossils, the most famous being that of skeleton Lucy, which is at least 3 million years old, this is the oldest Homo evidence that has ever come to light.

Scientists from Arizona State University say that the fossils they have discovered in Ethiopia belong to our ancestors, being closer to modern day humans than the oldest, more apelike members of the human family tree.

The importance of the discovery, says William Kimbel, the director of ASU’s Institute of Human Origins, is that it adds a reference point in the timeline of human ancestry from a period that is very mysterious.

Human history is a puzzle for many scientists. It starts more than 3 million years ago, in the regions of Eastern Africa, where different ape-like creatures, the Australopithecus, lived. Lucy was one of them. In the next 500.000 years, these creatures went extinct and then our genus, Homo, appears in the same place.

From the evidence they have discovered in Ethiopia, the scientists were able to draw some conclusions over the general behavior and appearance of this human ancestor who walked the Earth 2.8 million years ago.

It walked on two feet and preferred a more dry climate. Researchers are trying to figure out what did it diet consisted of and whether he used stone tools or not.

The jaw has symmetrical premolars, slim molars and it is evenly proportioned, which is a feature of the Homo branch.

The find took more than a decade of research and searching.

“It took us almost 13 years to find this human ancestor. It doesn’t mean that the work that we did was wasted up until that time. But when we did find this jaw, we were pretty excited,” said Professor Kaye Reed, co-leader of the team who made the discovery.

Image source: NPR