What did the world look like when Ida lived? Who lived together with Ida? How did Ida live? How did Ida die? How was Ida found? How is research on Ida done? What do we do with fossils like this? Which primates of today can Ida be compared with? Even though the initial interpretation of her evolutionary relationships was wide of the mark, Ida is the most spectacular prehistoric primate specimen ever found.
For the most part, the record of fossil primates is one of teeth, isolated bits of skeleton, and bone fragments. The archaic lemur cousin is mostly mentioned in papers about other fossil primates. When Jens Lorenz Franzen and colleagues described Darwinius in , the paleontologists said little about how the young primate actually lived. After examining the pathology anew through micro-CT analyses, Franzen and co-authors suggest that Ida suffered an early injury that stayed with her for the rest of her ancient life.
The bones of the lower arm — the radius and ulna — are articulated with the carpals of the wrist and the metacarpals of the palm.
There is just a bump of spongy bone between the lower arm and the hand. While Ida could probably still rotate her forearm and move her fingers, the bone callus limited the flexibility of her wrist and the movement of her palm.
The researchers behind the new study suspect that Ida may have broken her wrist while falling out of the prehistoric canopy. I feel for Ida — I broke my right wrist in a similar way when I fell off a skateboard as a child. This is only one possible scenario, though. All we know is that she sustained such an injury. Regardless of how it happened, though, Frazen and collaborators propose that Ida suffered her injury at an especially vulnerable time.
She had to climb trees and scamper over branches on her own, yet she had a painful, debilitating injury. Indeed, Franzen and colleagues point out that Ida is truly exceptional because the primates of the Messel oil shale are usually only found as rare fragments that have been damaged by predators. At least three Messel primate fossils exhibit bite marks, and part of a primate jaw was even found inside fossil feces possibly left behind by an Eocene otter.
This means that amphibious carnivores were often responsible for transporting primate bodies to a part of the lake where the remains had a chance of preservation, but it also makes Ida even more of an outlier. If most Messel primate fossils are scraps left over from amphibious predator meals, then why was Ida left untouched? But it appears to have paid off. Hurum chose Ida's nickname because the diminutive creature is at the equivalent stage of development as his six-year-old daughter.
Hurum said Ida is very excited about her namesake. The fossil's amazing preservation means that the scientific team has managed to glean a huge amount of information from it, although this required new X-ray techniques that had not previously been applied to any other specimens. The researchers believe it comes from the time when the primate lineage , that diversified into monkeys, apes and ultimately humans, split from a separate group that went on to become lemurs and other less well known species.
Crucially though, Ida is not on the lemur line because she lacks two key characteristics shared by lemurs — a grooming claw on her second toe and a fused set of teeth called a tooth comb. Also, a bone in her ankle called the talus is shaped like members of our branch of the primates.
So the researchers believe she may be on our evolutionary line dating from just after the split with the lemurs. According to the team's published description of the skeleton in the journal PLoS ONE , Ida was 53cm long and a juvenile around six to nine months old. The team can be sure Ida is a girl because she does not have a penis bone. The unprecedented preservation of Ida meant working out how she died was more like a modern day crime scene investigation than the informed guess-work that palaeontologists usually make do with.
The team noticed that she had a broken wrist that had begun to partially heal.
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