Ida has several characteristics shared by humans such as an opposable thumb, relatively short arms and legs, and forward facing eyes. But she may not have been on the same branch of our family tree, says a new study.
Credit: The Link
SYDNEY: Earlier this year a fantastically preserved 47-million-year-old primate, was the subject of a heated debate. But a new study says it can’t possibly be an ancestor of humans.
Erik Seiffert, and his team, did an extensive analysis, detailed in the British journal Nature this week, which looking at 360 anatomical features of 117 living and extinct primates.
They also took a closer look at the jaw and teeth of a newly discovered 37-million-year-old Eocene primate from Africa, named Afradapis – a relative of Darwinius, the species at the centre of the controversy.
“Our analysis of early primate relationships is the largest that has ever been undertaken, and our results indicate that Afradapis and Darwinius played no role in the origin of higher primates,” said Seiffert, an anatomist at Stony Brook University, in New York, USA.
Largest yet study
The controversy began when a team led by Jørn Hurum, from the Natural History Museum in Oslo, Norway, published a paper in May 2009 which described the discovery of Darwinius masillae, an early primate they dubbed 'Ida' (see ”Astounding primate fossil excites experts”).
Their analysis placed her in a category alongside the ancestors of monkeys, apes and humans, on the basis that she had primitive features that were similar to those species. These traits included a monkey-like jaw, spatula shaped teeth, a short face and a steeper ankle joint.
The press machine surrounding the announcement – which simultaneously released a book and a DVD narrated by David Attenborough – referred to Ida as a ‘missing link’ in the early history of primates – an idea which some experts discounted as conjecture.
Convergent evolution
Seiffert said his new data suggests that Ida and her close relatives (the adapiforms) are instead part of the 'strepsirrhine' sister group to monkeys and apes, which includes modern lemurs.
“Our analysis indicates that adapiforms were the first African primates to show the specialised tooth and jaw features that are seen in living anthropoids [monkey, apes and humans],” Seiffert said.
According to him, however, these similarities found in Darwinius and Afradapis developed coincidentally in a process known as convergent evolution.
Jonathan Perry, an anatomist from Midwestern University, and co-author on Seiffert’s paper, added that the traits seen in these species appear to be more complex than some found in apes that appeared later. This suggests that they may have developed the similarities simply because they shared the same eating habits, he said.
