Monday , April 12 2021

Fossils shed light on human origins

Sophisticated scanning technology reveals intriguing secrets about Little Foot, the fossil of a human forerunner who inhabited South Africa 3.67 million years ago at a critical time in our evolutionary history.

Scientists said Tuesday they examined key parts of the nearly complete and well-preserved fossil at Britain’s national synchrotron facility, Diamond Light Source.

The scan focused on the cranial vault of Little Foot (the top of his safe) and his lower jaw or jaw.

The researchers learned not only about the biology of Little Foot species, but also about the difficulties this individual, an adult female, encountered during her lifetime.

Little Foot species mixed features similar to apes and humans and are considered a possible direct ancestor of humans.

Paleoanthropologist Ron Clarke of the University of the Witwatersrand, who unearthed the fossil in the 1990s in the Sterkfontein Caves northwest of Johannesburg and co-authored the new study, has identified the species as Australopithecus prometheus.

“In the cranial vault, we could identify the vascular channels of the spongy bone that are likely to be involved in brain thermoregulation, such as cooling the brain,” said Cambridge University paleoanthropologist Amelie Beaudet, who led the study. published in e-Life magazine.

“This is very interesting, as we didn’t have much information about this system,” added Beaudet, who noted that it probably played a key role in increasing the size of the triple brain, from Australopithecus to modern humans.

Little Foot’s teeth were also revealing.

“The dental tissues are very well preserved. She was relatively old, as her teeth are quite worn,” Beaudet said, though the exact age of Little Foot has not yet been determined.

The researchers detected defects in tooth enamel that indicate two crises of physiological stress in childhood, such as disease or malnutrition.

“There is still much to learn about the biology of early hominins,” said study co-author Thomas Connolley, chief scientist of Diamond’s beam line, with a term that encompasses modern humans and some extinct members of the lineage human evolution.

“Synchrotron X-ray imaging allows fossil specimens to be examined in a manner similar to computed tomography with radiography of a patient, but in much more detail.”

Little Foot, whose nickname reflects the small bones of the foot that were found among the first elements of the skeleton found, was about 130 cm tall. Little Foot has been compared in importance to the fossil named Lucy, which is about 3.2 million years old and is less complete.

Both are species of the genus Australopithecus but had different biological features, just as modern humans and Neanderthals are species of the same genus -Homo-, but with different characteristics. Lucy’s species is called Australopithecus afarensis.

“Australopithecus could 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 would be the best candidate to be our direct ancestor,” Beaudet said.

Our own species, Homo sapiens, first appeared about 300,000 years ago.

Synchrotron results are based on previous research on Little Foot.

The species was able to walk fully upright, but had features that suggest it was still climbing trees, perhaps sleeping there to avoid large predators. He had gorilla-like facial features and powerful hands for climbing. His legs were longer than his arms, as in modern humans, which makes this older hominin definitely have that trait.

“All of the earlier skeletal remains of Australopithecus have been partial and fragmentary,” Clarke said.

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