littor...@gmail.com wrote:
Atypical tooth wear found in fossil hominins also present in a Japanese macaque population
Ian Towle cs 2022 doi 10.1002/ajpa.24500
The real facts...
https://scitechdaily.com/strange-tooth-discovery-prompts-rethink-of-human-evolution/
...
The study, published in the American Journal of Biological Anthropology, concluded the ‘toothpick’-like grooves on back teeth and large uniform scratches on the macaques’ front teeth were actually caused by something
more mundane, yet still surprising – eating shellfish from rocks and accidentally chewing grit and sand with their food.
...
“Although this does not mean hominins were not placing tools in their mouths, our study suggests the accidental ingestion of grit and/or normal food processing behaviors could also be responsible for these atypical wear patterns.”
...
"eating shellfish from rocks"
The pictures show macaques using their teeth to pry limpets from dry rocks
https://onlinelibrary.wiley.com/doi/10.1002/ajpa.24500
Abstract
Objectives
Atypical tooth wear, including macroscopically visible striations on anterior teeth and within root grooves on posterior teeth, are often regarded as evidence of non-masticatory, tool use behavior in fossil hominins. Both these types of dental tissue loss are often considered unique to the genus Homo
and suggested to be the earliest evidence of human cultural habits. The aim
of this study was to describe similar tooth wear found in a wild primate population and to conduct a differential diagnosis of this atypical tissue loss.
Materials and Methods
The focus of this study was a sample of wild Japanese macaques from
Koshima Island, Japan. Individuals were provisioned regularly on the beach
as part of one of the longest running primate field sites. Tooth wear and fractures in this group were compared to two other non-provisioned
populations. Information on diet and behavior were obtained from extensive literature and on-going field observations.
"The limpet species commonly consumed, Cellana toreuma, is typically
dislodged from rocks utilizing the mouth (Figure 6a), followed by removing
the edible contents using the anterior dentition (Figure 6b). The exact
actions
involved, and the frequency of the behavior, likely varies from individual to individual and through time. Teeth must regularly contact rocks that limpets are attached to during extraction, and also the hard shell when contents are removed using the anterior dentition. Given the hardness of these materials, this process may contribute to the formation of the macrostriations visible, and therefore also to the atypical wear observed. Lastly, the role of other hard dietary items cannot be ruled out, since this group has also been
observed eating acorns and other items containing a hard coating."
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