(Reuters) – Sophisticated scanning technology reveals intriguing secrets about Little Foot, the remarkable fossil of an early human forerunner that inhabited South Africa 3.67 million years ago at a critical time in our evolutionary history.
Scientists said on Tuesday that they had examined the most important parts of the almost complete and well-preserved fossil in the British synchrotron plant, Diamond Light Source. The scan focused on Little Foot’s cranial arch – the upper part of her brainstem – and her lower jaw, or lower jaw.
The researchers not only gained insight into the biology of Little Foot’s species, but also into the hardships that this individual, an adult female, encountered during her lifetime.
Little Foot’s species have mixed ape-like and human-like characteristics and are considered a possible direct ancestor of humans. The paleoanthropologist of the University of the Witwatersrand Ron Clarke, who excavated the fossil in the Sterkfontein caves north of Johannesburg in the nineties and is co-author of the new study, identified the species as Australopithecus prometheus.
“In the coronary artery, we were able to identify the vascular canals in the spongy bone that are likely involved in brain thermoregulation – how the brain cools,” said Cambridge University anthropologist Amélie Beaudet, who led the study published in the journal e-Life has been published. .
“This is very interesting because we did not have much information about the system,” Beaudet added, noting that it probably played a key role in the triple increase in brain size of Australopithecus to modern humans.
Little Foot’s teeth were also exposed.
‘The tooth tissues are really well preserved. She was relatively old because her teeth were quite worn out, ”Beaudet said, although Little Foot’s exact age has not yet been determined.
The researchers noticed defects in the tooth enamel that indicate two attacks of physiological stress such as disease or malnutrition.
“There’s still a lot to learn about early hominin biology,” said Thomas Connolley, co-author of the study. He used a term that includes modern humans and certain extinct members of the human evolutionary generation. “Synchrotron X-ray imaging makes it possible to examine fossil samples in a similar way to a hospital X-ray CT scan of a patient, but in much greater detail.”
Little Foot, whose name reflects the small foot bones, which was one of the first elements of the skeleton, stood about 130 cm long. Little Foot is in importance compared to the fossil named Lucy which is about 3.2 million years old and less complete.
Both are species of the genus Australopithecus, but have different biological characteristics, just as modern humans and Neanderthal species are of the same species – Homo – but have different characteristics. Lucy’s species is called Australopithecus afarensis.
“Australopithecus can be the direct ancestor of Homo – humans – and we really need to learn more about the different species of Australopithecus in order to decide which one would be the best candidate to be our direct ancestor,” Beaudet said.
Our own species, Homo sapiens, first appeared about 300,000 years ago.
The synchrotron findings build on previous research on Little Foot.
The species could walk completely upright, but has characteristics that indicate that it also still climbed trees, perhaps sleeping there to avoid large predators. It has gorilla-like features and powerful hands to climb. His legs were longer than his arms, as in modern man, making it the oldest hominin that definitely had the trait.
“All previous skeletal remains of Australopithecus were partial and fragmentary,” Clarke said.
Reporting by Will Dunham in Washington, Editing by Rosalba O’Brien