Inside the head of Little Foot: Researchers reconstruct the brain of 3.7 million year old ancestor

0
13
MicroCT scans of the Australopithecus fossil were used to reconstruct the brain, and reveal a small brain combining ape-like and human-like features


Inside the head of Little Foot: Researchers reconstruct the brain of our 3.7 million year old ancestor

  • MicroCT scans of the Australopithecus fossil were used to reconstruct the brain
  • Scans to reveal impressions left on the skull by the brain and its vessels

Mark Prigg For Dailymail.com

Researchers have reconstructed the brain of Little Foot, a controversial hominin which lived 3.67 million years ago.

Amid a swirling debate over whether the elderly female skeleton is a new separate species, researchers managed to reconstruct the brain.

It reveals a small brain combining ape-like and human-like features.  

MicroCT scans of the Australopithecus fossil were used to reconstruct the brain, and reveal a small brain combining ape-like and human-like features

MicroCT scans of the Australopithecus fossil were used to reconstruct the brain, and reveal a small brain combining ape-like and human-like features

THE ROW OVER LITTLE FOOT 

Four scientific papers, which are yet to be peer-reviewed or published, claim the skeleton of an elderly female with a crippled left arm proves she does not belong to any known category, and should therefore be recognised as a new species. 

The Australopithecus fossil named Little Foot, an ancient human relative, was excavated over 14 years from the Sterkfontein Caves in South Africa, by Professor Ronald Clarke, from the University of the Witwatersrand (Wits). 

‘Our ability to reconstruct features of early hominin brains has been limited by the very fragmentary nature of the fossil record,’ said Wits researcher, Dr Amélie Beaudet, who led the research.

‘The Little Foot endocast is exceptionally well preserved and relatively complete, allowing us to explore our own origins better than ever before.’  

MicroCT scans of the Australopithecus fossil known as Little Foot shows that the brain of this ancient human relative was small and shows features that are similar to our own brain and others that are closer to our ancestor shared with living chimpanzees.

The team used the scans to reveal impressions left on the skull by the brain and the vessels that feed it, along with the shape of the brain. 

While the brain features structures similar to modern humans – such as an asymmetrical structure and pattern of middle meningeal vessels – some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.

The skeleton dates back 3.6 million years. Four scientific papers, which are yet to be peer-reviewed or published, claim the skeleton of an elderly female with a crippled left arm proves she does not belong to any known species of human ancestor

The skeleton dates back 3.6 million years. Four scientific papers, which are yet to be peer-reviewed or published, claim the skeleton of an elderly female with a crippled left arm proves she does not belong to any known species of human ancestor

The skeleton dates back 3.6 million years. Four scientific papers, which are yet to be peer-reviewed or published, claim the skeleton of an elderly female with a crippled left arm proves she does not belong to any known species of human ancestor

The endocast showed that Little Foot’s brain was asymmetrical, with a distinct left occipital petalia. 

Brain asymmetry is essential for lateralisation of brain function. 

Asymmetry occurs in humans and living apes, as well as in other younger hominin endocasts. 

Little Foot now shows us that this brain asymmetry was present at a very early date (from 3.67 million years ago), and supports suggestions that it was probably present in the last common ancestor of hominins and other great apes.

While the brain features structures similar to modern humans - such as an asymmetrical structure and pattern of middle meningeal vessels - some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.

While the brain features structures similar to modern humans - such as an asymmetrical structure and pattern of middle meningeal vessels - some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.

While the brain features structures similar to modern humans – such as an asymmetrical structure and pattern of middle meningeal vessels – some of its critical areas such as an expanded visual cortex and reduced parietal association cortex points to a condition that is distinct from us.

Other brain structures, such as an expanded visual cortex, suggests that the brain of Little Foot probably had some features that are closer to the ancestor we share with living chimpanzees.

‘In human evolution, when know that a reduced visual cortex, as we can see in our own brain, is related to a more expanded parietal cortex – which is a critical cerebral area responsible for several aspects of sensory processing and sensorimotor integration,’ says Beaudet. 

‘On the contrary, Little Foot has a large visual cortex, which is more similar to chimpanzees than to humans.’

FINDING LITTLE FOOT 

In 1994, Ron Clarke, a paleoanthropologist from the University of the Witwatersrand in South Africa, discovered the skeleton of Little Foot in Silberberg Grotto at Sterkfontein.

It is believed that she fell down a narrow shaft in the Sterkfontein Caves, leaving behind a nearly complete skeleton.

Dr Clarke discovered her remains – four foot bones – in 1994.

Then in July 1997, he and Stephen Motsumi and Nkwane Molefe, located the position of the end of the skeleton’s shin bone in the Sterkfontein caves.

In July 1997, Dr Clarke and Stephen Motsumi and Nkwane Molefe (pictured), located the position of the end of the skeleton's shin bone in the Sterkfontein caves

In July 1997, Dr Clarke and Stephen Motsumi and Nkwane Molefe (pictured), located the position of the end of the skeleton's shin bone in the Sterkfontein caves

In July 1997, Dr Clarke and Stephen Motsumi and Nkwane Molefe (pictured), located the position of the end of the skeleton’s shin bone in the Sterkfontein caves

The study also has shown that the vascular system in Australopithecus was more complex than previously thought, which raises new questions on the metabolism of the brain at this time.  

‘This would mean that even if Little Foot’s brain was different from us, the vascular system that allows for blood flow (which brings oxygen) and may control temperature in the brain – both essential aspects for evolving a large and complex brain – were possibly already present at that time,’ says Beaudet.

Given its geological age of over 3 million years, Little Foot’s brain suggests that younger hominins evolved greater complexity in certain brain structures over time, perhaps in response to increasing environmental pressures experienced after 2.6 million years ago with continuing reduction in closed habitats.

‘Such environmental changes could also potentially have encouraged more complex social interaction, which is driven by structures in the brain,’ says Beaudet.

 

Advertisement





Source link

LEAVE A REPLY

Please enter your comment!
Please enter your name here