Wednesday, 3 March 2021

Evolution News - A 3.67 Million-Year-Old Hominin Skull CT Scan Shows Amazing Detail.

Fossil skull ("Little Foot")
New technology allows scientists first glimpse of intricate details of Little Foot’s life - - Diamond Light Source

It must be difficult for a dedicated creationist to have to live with these regular accounts of things happening many millions of years before their dogma requires them to believe the Universe existed, but then I suppose as would be Christian martyrs, they like a cross to bear.

So here for them then is yet another one. This is a scientific account of the amazingly detailed examination of a 3.67 million-year-old hominid skull from South Africa, using a new technology that allows fragile speciments to be non-destructively examined.

The skull is that of a female Australopithecine - a genus of hominin that were the immediate ancestors of the Homo genus, were widely distributed in eastern and southern Africa.
This examination was made possible by using a technology developed just a stone's throw from where I live, by Diamond Light Source - the UK's national synchrotron science facility at Harwell Science and Innovation Campus in Southeast Oxfordshire.

The Diamond Light news release explains:
In June 2019, an international team brought the complete skull of the 3.67-million-year-old ‘Little Foot’ Australopithecus skeleton, from South Africa to the UK and achieved unprecedented imaging resolution of its bony structures and dentition in an X-ray synchrotron-based investigation at Diamond. The X-ray work is highlighted in a new paper in e-Life, published today focusing on the inner craniodental features of ‘Little Foot’. The remarkable completeness and great age of the ‘Little Foot’ skeleton makes it a crucially important specimen in human origins research and a prime candidate for exploring human evolution through high-resolution virtual analysis.

We had the unique opportunity to look at the finest details of the craniodental anatomy of the ‘Little Foot’ skull. While scanning it, we did not know how well the smallest structures would be preserved in this individual, who lived more than 3.5million years ago. So, when we were finally able to examine the images, we were all very excited and moved to see such intimate details of the life of ‘Little Foot’ for the first time. The microstructures observed in the enamel indicate that Little Foot suffered through two clear periods of dietary stress or illness when she was a child.

Dr Amélie Beaudet, Lead author and Principal Investigator
Department of Archaeology, University of Cambridge, UK
And Honorary Research Fellow, University of the Witwatersrand, South Africa
To recover the smallest possible details from a fairly large and very fragile fossil, the team decided to image the skull using synchrotron X-ray micro computed tomography at the I12 beamline at Diamond, revealing new information about human evolution and origins. This paper outlines preliminary results of the X-ray synchrotron-based investigation of the dentition and bones of the skull (i.e., cranial vault and mandible).

The team were also able to observe and describe the vascular canals that are enclosed in the compact bone of the mandible. These structures have the potential to reveal a lot about the biomechanics of eating in this individual and its species, but also more broadly about how bone was remodelled in ‘Little Foot’. The branching pattern of these canals indicates some remodelling took place, perhaps in response to changes in diet, and that 'Little Foot' died as an older individual.
This movie was created by Dr. Nghia T. Vo and Dr. Robert C. Atwood at Diamond Light Source. The first part of the movie is an animated series of slices, the second part is a 3D render of the external features of the skull. The visualisation was created by downsampling some of the data generated during the experiments at Diamond by the ‘Little Foot’ research team from the University of Witwatersrand, South Africa.

Film: Diamond Light Source Limited and Witwatersrand University.
The team also observed tiny (i.e., less than 1 mm) channels in the braincase that are possibly involved in brain thermoregulation (i.e., how to cool down the brain). Brain size increased dramatically throughout human evolution (about threefold), and, because the brain is very sensitive to temperature change, understanding how temperature regulation evolves is of prime interest...
The first bones of the ‘Little Foot” fossil were discovered in the Sterkfontein Caves, northwest of Johannesburg, by Professor Ron Clarke of the University of the Witwatersrand in 1994. In 1997, following their discovery of the location of the skeleton, Professor Clarke and his team spent more than 20 years painstakingly removing the skeleton in stages from the concrete-like cave breccia using a small airscribe (a vibrating needle). Following cleaning and reconstructing, the skeleton was publicly unveiled in 2018. Wits University is the custodian of the StW 573, ‘Little Foot’, fossil.
2D sections of the roots of the upper right first molar (A,B), of the cranial vault (C,D), and of the mandibular symphysis (E) of StW 573.
The close up (B) of the roots of the upper right third premolar shows the dentine–cementum junction. The Haversian canals of the mandibular symphysis is reconstructed in 3D (F) in the same orientation as in (E). 1: dentine; 2: cementum; 3: calcite; 4: trabecular bone; 5: incremental line in the cementum; 6: diploic bone; 7: inner table; 8: diploic channel; 9: outer table; 10: Haversian canals; 11: dichotomous branching; 12: transverse connection.
The teams findings were published open access in eLife a couple of days ago:

Abstract


Numerous aspects of early hominin biology remain debated or simply unknown. However, recent developments in high-resolution imaging techniques have opened new avenues in the field of paleoanthropology. More specifically, X-ray synchrotron-based analytical imaging techniques have the potential to provide crucial details on the ontogeny, physiology, biomechanics, and biological identity of fossil specimens. Here we present preliminary results of our X-ray synchrotron-based investigation of the skull of the 3.67-million-year-old Australopithecus specimen StW 573 (‘Little Foot’) at the I12 beamline of the Diamond Light Source (United Kingdom). Besides showing fine details of the enamel (i.e., hypoplasias) and cementum (i.e., incremental lines), as well as of the cranial bone microarchitecture (e.g., diploic channels), our synchrotron-based investigation reveals for the first time the 3D spatial organization of the Haversian systems in the mandibular symphysis of an early hominin.

3D renderings of the buccal aspect of the enamel surface of the lower left canine of StW 573 using synchrotron-based data sets at 21.23 (A) and 7.91 µm (B). The black arrows (A) point to enamel defects. 3D reconstructions are superimposed (C) and the distances between them are rendered by a pseudo-color scale ranging from dark blue (lowest values) to red (highest values).
The significance of this work is not the trivially easy one of debunking Creationism since that is done quite casually and without special effort by masses of science papers on a daily basis, but that it shows how advances in science and technology itself, such as these advances that enables this precision of CT scan to be carried out, lead to the accumulation of ever-increasing and improving knowledge and understanding of the truth of human ancestry.

For example, examining the blood vessels that supplied the brain in the Australopithecines can show how the blood supply to our own brain evolved over time and allowed our relatively large brain to develop and work while staying comparatively cool.

For a Creationist, there should be a lot to fear from these rapid advances and the knowledge that we can begin to piece together an event from 3.67 million years ago that led to this proto-human ending up with a lot of other dead animals in a cave. We alredy know that she had a difficult childhood, since the enamel on her teeth shows she had two periods of stress - either starvation or illness - that caused defects in the growth of her teeth.








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