Research argues that 'long lost ancestor of humanity' is actually just a different kind of primate
Dr Jørn Hurum named the fossil after his daughter and claimed it was a 'world sensation'. Photograph: Atlantic Production
Tear up the wallchart documenting "humanity's long lost ancestor". Correct the recently altered "primate family tree" [pdf]. Dismiss the 3.7bn year timeline "from bacteria to mammals" [pdf]. Ignore the front page comment by Sir David Attenborough.
Ida, the 47 million-year-old fossil described as the "first link in human evolution" and vociferously championed by the media (including the Guardian) earlier this year, is no such thing, according to a team of scientists. They say that Ida is, instead, from a "group of extinct primates" that are "not ancestors" to humans.
The skull of Ida the missing link primate fossil In unhappier times: skull of Ida, the fossil now being discounted as the 'missing link'. Photograph: Atlantic Productions Ltd
The initial unveiling of the fossil by Dr Jørn Hurum, described as "a bit of a showman" and "a real-life Indiana Jones", set palaeontological pulses racing in May this year.
Ida, named after Hurum's daughter, was hailed by some as a "missing link" between animals and humans.
The team identified Ida as having lived at around the time the biological order of primates was splitting into distinct branches – our branch of the primates (the haplorhines), which includes monkeys and apes, split from a second group including lemurs, lorises, pottos and bush babies (the strepsirrhines).
Ida was exciting because of her lack of lemur-like physical characteristics – no fused teeth in the middle of her lower jawbone, no grooming claw – suggesting she was from the newly developed "human branch" of primates.
Presenting his findings, Hurum said Ida was the "first link in human evolution": the first step towards the branch of primates from which humans, apes and monkeys developed.
It was an exciting time. Attenborough presented a BBC1 documentary about the discovery and claimed: "This little creature is going to show us our connection with the rest of all the mammals – with cows and sheep, and elephants and anteaters."
However, Ida's significance is being called into question by a paper that will be published in the science magazine Nature tomorrow.
A team led by Erik Seiffert, from Stony Brook University in New York, examined a 37 million-year-old primate, which they describe as a close relative of Ida. Like Ida, the fossil shares several features with higher primates, the branch that includes humans.
But Seiffert says both mammals belong to the adapoids – a group of extinct primates that are not related to humans.
"Phylogenetic analysis of over 300 characteristics across 117 living and extinct primates reveals that the adapoids are not ancestors to higher primates but rather a separate lineage with no known descendants," Seiffert said.
"This means that the features they share with higher primates, such as the loss of the upper and lower second premolar, must have evolved independently."
The story is a little embarrassing as the Guardian's coverage of Ida was particularly vigorous. The items listed in the opening paragraph were all located within these pages on 20 May 2009.
Looking back at the coverage, some of the elements surrounding the discovery of Ida are a little unorthodox.
The significance of the fossil was not initially realised using modern scientific techniques. Instead, Hurum was in a vodka bar – not a regular frontier of science – when he first looked at photographs of Ida, apparently unearthed from Messel Pit in Germany by an enterprising collector in 1983.
"My heart started beating extremely fast," Hurum said in May. "I knew that the dealer had a world sensation in his hands. I could not sleep for two nights."
Dozens of newspaper pages were devoted to the "missing link" – the Guardian alone ran the story over five pages on 20 May. Amid the hyperbole it was possible to find some words of caution. The newspaper carried a warning from John Fleagle, a professor at Stony Brook University, who challenged the findings. Fleagle stressed Ida's full significance would not be known until other scientists had seen the paper.
"That will be sorted out, or at least debated extensively, in the coming years," he said. Now, it seems, that debate has begun.
So are cetaceans, if you want to go that far. Perhaps I should've said 'direct descendant'...
