Missing link? Ida, the 47-million-year-old fossil of a lemur that could change the way we understand human evolution









Scientists find the 'missing link': a 47million-year-old lemur that could revolutionise how we see human evolution

By David Derbyshire
19th May 2009

Her name is Ida, she is three feet tall and if the scientists are right, she could be a common ancestor of all apes, monkeys and people.

In one of the most important fossil discoveries for years, researchers today revealed the beautifully preserved remains of a lemur-like creature who died in a lake 47 million years ago.

Ida is so perfectly fossilised, it is possible to see the outline of her fur in the rock and even the traces of her last meal.

The scientists who presented the fossil today claimed she was an important 'missing link' in mankind's family tree - and helps shed light on a crucial part of evolution.

But some independent experts are sceptical about the fossil and claim her unveiling - timed to coincide with a lucrative book and television documentary - own more to showbiz than science.

Ida was discovered in the 1983 in a fossil treasure trove called the Messel Pit in Germany by private collectors who split the skeleton in two and sold both halves.

Ida is so perfectly preserved that there are still traces of her last meal in her stomach - and outlines of her fur can be seen etched into the stone

The skeleton shows distinct physical characteristics of human beings - like hands that can grasp things, and opposable thumbs

For the past two years, an international team of scientists, led by  Dr Jørn Hurum of the University of Oslo Natural History Museum secretly conducted a forensic analysis of the fossil.

Dr Hurum said the fossil would be pictured in 'all the text books' for the next 100 years.

'This is the first link to all humans,' he said. 'Truly a fossil that links world heritage.'

He added: 'This fossil is so complete. Everything’s there. It’s unheard of in the primate record at all. You have to get to human burial to see something that’s this complete.'

Dr Jens Franzen, another of the researchers, described Ida as 'like the Eighth Wonder of the World', because of the extraordinary completeness of the skeleton.

An X-ray of Ida's teeth. She still had not shed all her baby (deciduous) teeth when she died. Scientists believe she was only about nine months old

CTs of Ida's entire skull, including her jaw and teeth, seen in greater detail above

But rather than being a direct ancestor of mankind, he said she was more likely to be an 'aunt' rather than a 'grandmother'.

'She belongs to the group from which higher primates and human beings developed but my impression is she is not on the direct line,' he said.  

Professor Philip Gingerich - Museum of Palaeontology, University of Michigan, was equally enthusiastic.

'It’s really a kind of Rosetta Stone,' he said.

The findings are published in the journal PLoS One.

The two halves of Ida. The skeleton was split in half on its discovery in 1983, with the two parts going to different collections

Ida is 20 times older than most fossils that can shed light on human evolution. She comes from a period when the primate family tree was splitting into two groups - one containing humans, apes and monkeys, the other containing lemurs and bush babies.

The team concluded that she was not simply another lemur, but a new species called Darwinius masillae- after her place of discovery and to mark the bicentennial of Darwin's birth.

Sir David Attenborough - pictured here with a real lemur - will present a documentary on Ida to be aired on the BBC

They also believe she lies close to the human-monkey-ape branch.

She lacked two of the key anatomical features found in lemurs - a grooming claw on the second toe of the foot, and a fused row of teeth known as a 'toothcomb'.

She also had nails like apes - rather than lemur claws - and her teeth were similar to monkey's. Her forward facing eyes were like human eyes, while she had humanlike opposable thumbs.

The creature was a young female who died aged nine months.  Her stomach contained traces of fruits, seeds and leaves. The skeleton is intact apart from a piece of tail.

The researchers are even able to speculate on the cause of death. Her left wrist was healing from bad fracture. They believe she may have been overcome by carbon dioxide gas while drinking from a volcanic lake.

Struggling with an injury arm she may have slipped unconscious and been washed into the lake. The unique conditions at the bed of the lake preserved her.

Sir David Attenborough, who will present a BBC documentary on the discovery next Tuesday, said: 'This little creature is going to show us our connection with the rest of all mammals. The link they would have said until now is missing… is no longer missing.'

Independent experts were more cautious.

Dr Henry Gee, a senior editor at the journal Nature, said the use of the term 'missing link' was misleading.

'It's extremely nice to have a new find and it will be well-studied,' he said. 

Article: HERE