Is this the FIRST man? Fossil jawbone of 2.8 million-year-old human ancestor discovered that could be our earliest relative
Jawbone – known as LD 350-1 – was discovered in Afar region of Ethiopia
The fossil may have belonged to the earliest member of the Homo family
It means that the Homo family emerged 400,000 years earlier than believed
Scientists think it could represent a common ancestor for all Homo species
The jaw shares features with other Homo fossils but is also more primative
Discovery has helped fill a huge gap in the fossil record of our evolution
Scientists say it could provide new clues about how our species evolved
By RICHARD GRAY and BEN SPENCER FOR THE DAILY MAIL
The first of our human ancestors emerged in Africa around 2.8 million years ago – 400,000 years earlier than previously thought, a newly discovered fossilised jawbone has revealed.
The partially complete lower jaw, which was uncovered in the Afar region of Ethiopia, is thought to belong to a species that may have been the first member of the Homo family.
This would make it the common ancestor for modern humans – Homo sapiens – and their extinct relatives including Homo habilis, Homo erectus and Neanderthals.
The fossilised lower jawbone, shown above with teeth still in the bone, was found in Ledi-Geraru in Ethiopia
Scientists say the fossil, which is known as LD 350-1, is recognisably human but also has more primative features that suggests it is older than other fossils belonging to the Homo family.
Researchers who have digitally reconstructed the jaws of other ancient human ancestors say the fossil also matches what they would expect from this common ancestor.
THE COMPLEX EVOLUTION OF MAN
55 million years ago – First primitive primates evolve
15 million years ago – Hominidae (great apes) evolve from the ancestors of the gibbon
8 million years ago – First gorillas evolve. Later, chimp and human lineages diverge
5.5 million years ago – Ardipithecus, early ‘proto-human’ shares traits with chimps and gorillas
4 million years ago – Australopithecines appeared. They had brains no larger than a chimpanzee’s
2.8 million years ago – LD 350-1 appeared and may be the first of the Homo family
2.7 million years ago – Paranthropus, lived in woods and had massive jaws for chewing
2.3 million years ago – Homo habalis first thought to have appeared in Africa
1.8 million years ago – Homo ergaster begins to appear in fossil record
1.6 million years ago – Hand axes become the first major technological innovation
800,000 years ago – Early humans control fire and create hearths. Brain size increases rapidly
400,000 years ago – Neanderthals first begin to appear and spread across Europe and Asia
200,000 years ago – Homo sapiens – modern humans – appear in Africa
40,0000 years ago – Modern humans reach Europe
The discovery, which was found in the Ledi-Geraru area of Afar, has put a new date on the emergence of the first ‘man’ from our more ape-like ancestors.
Dr Brian Villmoare, from the University of Nevada, Las Vegas, helped lead the fossil hunters, said: ‘In spite of a lot of searching, fossils on the Homo lineage older than two million years ago are very rare.
‘To have a glimpse of the very earliest phase of our lineage’s evolution is particularly exciting.
‘LD 350-1 reveals that many of the anatomical patterns we see in 2 million-year old Homo were established much earlier in the evolution of the genus.
‘At 2.8 million years ago we see relatively evolved Homo traits in combination with other much more primitive anatomical features.’
The researchers, whose work on the fossil is published in the journal Science, say the fossil could be a key missing link between the Homo lineage and a more primitive and ape-like rival branch of the hominin evolutionary tree called Australopithecus.
Details of the Australopithecus are best known from a fossil named ‘Lucy’, dating back 3.2 million years, which was discovered in Ethiopia in 1974.
But exactly how Homo habilis had appeared was unclear due to a huge gap in the fossil record.
The new discovery has helped to fill that gap.
Scientists say it can provide important clues to the changes in jaw and teeth that distinguished members of the Homo family from those belonging to Australopithecus.
Until now the earliest evidence of the existence of the first Homo species was 2.3 million to 2.4 million year old fossils.
Scientists have been searching for decades for earlier examples in an attempt to understand how our ancestors split from other ape-like hominins.
Dr William Kimbel, director of the Institute of Human Origins at Arizona State University who was also involved in the research, said: ‘The Ledi jaw helps narrow the evolutionary gap between Australopithecus and early Homo.
‘It’s an excellent case of a transitional fossil in a critical time period in human evolution.’
The fossilised jawbone was first discovered by student Chalachew Seyoum from the Authority for Research and Conservation of Cultural Heritage in Ethiopia in January 2013.
It is thought to be the left side of an adult’s lower jawbone that has canine, premolars and three molars still preserved in the jaw.
Mr Seyoum said he was ‘stunned’ when he saw the fossil.
‘The moment I found it, I realised that it was important, as this is the time period represented by few fossils in Eastern Africa,’ he told BBC News last night.
Dating of the fossil and the surrounding sediment suggest it is between 2.8 million and 2.75 million years old.
Other fossils of antelope, prehistoric elephants and hippos discovered alongside the jawbone suggest that this early Homo species lived in open grassland and shrub habitats.
This matches the picture that scientists believe was occurring around this time of climate change creating increasingly arid conditions in Africa.
These are thought to be one of the main driving forces that led to the evolution of the Homo lineage and eventually our own species.
Australopithecus, by contrast, was thought to inhabit far wetter environments and this may have contributed to their eventual demise.
The researchers said that the changes in the new jawbone compared to Australopithecus suggest that evolution of different jaw shapes may have been a key step in the divergence of the two lineages.
Professor Kaye Reed, also from Arizona State University, said: ‘We can see the 2.8 million year aridity signal in the Ledi-Geraru faunal community, but it’s still too soon to say that this means climate change is responsible for the origin of Homo.’
The new fossil has helped fill a huge gap in the evolutionary history (above) of how the Homo family appeared
Another study published in the journal Nature has also provided convincing evidence that LD 350-1 was a common human ancestor to the Homo family.
They used 3D imaging techniques to scan partial skull of Homo habilis – a human ancestor that lived 1.8 million years ago and is thought to have been among the first to use tools – earning it the nickname ‘handy man’.
It reveals an unexpectedly primitive structure, indicating that the species may have originated at least 2.3 million years ago and allowed the researchers to draw conclusions about what their ancestors jaw would have looked like.
Their findings suggest that three different species of early human existed side-by-side between 2.1 million and 1.6 million years ago – Homo habilis, Homo erectus and Homo rudolfensis.
Scientists used 3D imaging techniques to reconstruct the skull of Homo hablis (left) which has provided clues about how this now extinct member of our evolutionary branch would have looked. The image on the right shows an early reconstruction of Homo hablis at the Westfälisches Museum for Archaology in Herne
They found that the ancestor of Homo habilis would have had features similar to those found in the fossilised jawbone LD 350-1.
Professor Fred Spoor, a researcher of evolutionary anatomy at University College London and the Max Planck Institute in Germany, said: ‘By digitally exploring what Homo habilis really looked like we could infer the nature of its ancestor, but no such fossils were known.
‘Now the Ledi-Geraru jaw has turned up as if ‘on request’, suggesting a plausible evolutionary link between Australopithecus afarensis and Homo habilis.’
This reconstruction of the jaw of Homo habilis by the UCL team shows that it was more primitive than the jaws of Homo erectus or Homo sapiens and was more similar to the jaw of Australopithecus afarensis
Dr Simon Underdown, an anthropologist at Oxford Brookes University, said the discovery of LD 350-1 could help scientists unravel the complex beginnings of our own species.
He said: ‘It gives us a better understanding of what was happening at the earlier end of the genus Homo.
‘Finds like Kenyanthropus (a 3.5 million year old ape-like species) have made it harder to understand the relationship between the Australopithecines and us – in short it’s the replacement of the old fashioned unilinear model of a evolutionary branch with a multiple species based evolutionary bush.
‘What’s becoming clear is that we have only a small part of the jigsaw puzzle. This new fossil may well be a member of our genus, an australopithecine or an hitherto unknown genus.’