A new study published in the latest issue of the Journal of Human Evolution, found that the genus Paranthropus, one of the prehistoric humans species, does not deserve the Nutcracker Man title.
The Paranthropus group stands out in this family tree because of their massive back teeth, several times the size of ours, and their extremely thick enamel (the outer-most layer of our teeth). But the new study that examined Paranthropus' fossilized teeth and enamel found new evidence on its diet.
Researchers Ian Towle and Carolina Loch from the University of Otago, New Zealand, in collaboration with researcher Joel Irish from the University of Liverpool's School of Biology and Environmental Science, found that Paranthropus had very low rates of enamel chipping (a common type of tooth fracture), comparable to living primates such as gorillas and chimpanzees. This supports other recent research about the diet of this group and should finally put to rest the nutcracker hypothesis.
"Our understanding of diet and behavior during human evolution has changed markedly over the last decades — partly due to new technologies but also because of some spectacular fossil discoveries, mainly teeth," the researchers said in a report posted on The Conversation website, on July 24.
They explained that teeth are by far the most abundant resource because they survive fossilization better than bones. This is a fortunate circumstance because teeth also offer other information that helps us to reconstruct the environment of our fossil ancestors and relatives. We can glean a lot of information from the microscopic scratches created by foods scraping along the tooth surface during chewing, the tiny particles preserved in dental plaque and the chemical composition of the teeth themselves, they added.
Before such techniques were developed and refined, researchers relied on looking at the overall shape and size of teeth, as well as wear and chipping visible with the naked eye. Small sample sizes and a lack of comparative material hampered these studies, but they provided some bold claims about the diet of our fossil ancestors, including its reliance on hard foods.
"In our recent research, we have studied a broad range of living primates and compared that information with data on fossil species. The results were surprising, with our species Homo sapiens and fossil relatives in our genus commonly showing high rates of chipping, similar to living primates that eat hard foods habitually," they concluded.