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New research from the University of Otago debunks a long-held belief about the eating habits of our ancestors.
For more than 60 years, researchers believed that Paranthropus, a close fossil relative who lived around one to three million years ago, developed massive posterior teeth to consume hard foods such as seeds and nuts, while our own direct ancestors, the genus Homo is believed to have developed smaller teeth due to the consumption of softer foods such as cooked foods and meats.
However, after traveling to several major institutes and museums in South Africa, Japan and the UK and studying dental fractures in over 20,000 teeth from living fossils and primates, Dr Ian Towle, an anthropologist Otago biologist, in collaboration with Dr Carolina Loch, of the Faculty of Dentistry, says that “this sharp picture is much more complex than previously thought”.
“By studying each tooth individually and recording the position and size of all dental fractures, we show that tooth chipping does not support regular consumption of hard foods in Paranthropus robustus, potentially ending the argument. that this group as a whole were hard food eaters, “he says.
Dr Towle says the findings challenge our understanding of dietary and behavioral changes during human evolution.
“The results are surprising, with human fossils studied so far – those of our own genus Homo – showing extremely high rates of dental fractures, similar to living primates eating hard objects, but Paranthropus shows extremely low levels of fracture. , similar to primates that eat soft fruit or leaves.
“Although in recent years there has been a slow acceptance that another species of Paranthropus, Paranthropus boisei, found in East Africa, was unlikely to have regularly eaten hard foods, the idea that Paranthropus evolved his large dental apparatus to eat hard food persisted. Therefore, this research can be seen as the last nail in the coffin of Paranthropus as hard object feeders. “
The fact that humans exhibit such contrasting flaking patterns is equally important and will have ripple effects for future research, especially research on dietary changes during human evolution, and why human dentition evolved as it did, he said.
“Regular dental fractures in fossil humans can be caused by non-food items, such as gravel or stone tools. However, whatever the cause, these groups have been subject to wear and tear. This raises questions about why our teeth are reduced in size, especially compared to groups like Paranthropus. “
Dr. Towle’s research will now focus on whether our dentition has evolved smaller due to other factors to allow other parts of the skull to grow, leading to evolution and then promoting other dental properties to protect it against. wear and fractures, instead of an increase in the size of the teeth.
“This is something that we are now studying, to see if tooth enamel may have developed different characteristics in great apes. Our research as a whole may also have implications for our understanding of oral health,” since fossil human samples generally show pristine dental health.
“As extreme tooth wear and fractures were the norm, our ancestors probably developed dental characteristics not only to cope with this loss of tooth tissue, but to actually use it. , crowding of teeth and even increased susceptibility to cavities. “
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Paranthropus robustus tooth chipping models do not support regular chewing on hard food, co-authored by Dr Towle and Dr Loch, was published in the Journal of Human Evolution.
The prevalence and pattern of tooth chipping in extant primates, co-authored by Dr Towle and Dr Loch, has been published in the American Journal of Physical Anthropology.
Scaling and Wear Patterns in Fossil Primate and Hominid Molars: ‘Functional’ Cusps Associated with Heavy Wear but Low Levels of Fracture, Co-authored by Dr Towle and Dr Loch has been published in the Journal of Human Evolution.
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