A famous member of an extinct human group went through hard times early in her life. The fossil, known as Little Foot, has tell-tale signs in her teeth that suggest she was either deprived of food or seriously ill during her childhood. Analysis of the fossil also revealed blood vessels in the skull, which could help us better understand the evolution of human brains.
Little Foot lived about 3.67 million years ago in what is now South Africa. She was an ape-like hominin with a much smaller brain than modern humans. She belonged to the genus Australopithecus, but scientists disagree about her exact species. Little Foot was old when she died, and her remains were found with those of a baboon, suggesting she died in a fight.
To find out more details of Little Foot’s biology, Amélie Beaudet at the University of Cambridge in the UK and her colleagues scanned the fossil’s skull using the X-ray synchrotron at the Diamond Light Source in the UK. This allowed them to see details as small as 3 micrometres, compared to 100 micrometres in a CT scanner.
“In the teeth we can see some defects, like lines or grooves,” says Beaudet. “It means at some point the enamel could not form properly.” This must have happened during childhood when Little Foot’s body was still developing.
There are several possible explanations, says Beaudet. One is that Little Foot’s environment changed, perhaps because the climate shifted, and as a result she found herself short of food. “We know that the environment was not always stable,” says Beaudet.
But it is also possible that Little Foot was ill, perhaps due to an infection. “We cannot say it was because of a food shortage, or because she was sick, or something else,” says Beaudet.
The team was also able to see tiny blood vessels in the bones of the skull and lower jaw. Beaudet says it was a “big surprise” that the fossil was preserved well enough to see such details.
Understanding Little Foot’s blood supply may ultimately shed light on the evolution of our unusually large brains. The brain needs to receive a lot of nutrients, and generates heat that needs to be carried away. Blood does both, so as our ancestors’ brains evolved to be larger, the blood vessels must have also evolved. “What part of the system had to evolve first for the rest to happen?” asks Beaudet.
Journal reference: eLife, DOI: 10.7554/eLife.64804
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