Behavioral inferences from the high levels of dental chipping in <i>Homo naledi</i>

Towle, Ian; Irish, Joel D.; Groote, Isabelle De

doi:10.1002/ajpa.23250

Cited by 45 publications

(82 citation statements)

References 56 publications

(101 reference statements)

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“…Again, in the light of our findings this would make a dust‐loaded diet unlikely but rather suggests that this microwear signature was the result of small sized seeds. However, we cannot fully exclude the possibility that grit (sensu stricto—coarse sand with a grain size of 0.5–2 mm) caused these chips and was also involved in texture formation as suggested by Towle, Irish, and De Groote () and Berthaume, Delezene, and Kupczik (). Both fossil hominin examples show that more field observations and feeding experiments under controlled conditions are needed to better understand texture formation.…”

Section: Discussionmentioning

confidence: 82%

Dust affects chewing efficiency and tooth wear in forest dwelling Western chimpanzees (Pan troglodytesverus)

Schulz‐Kornas

Stuhlträger

Clauss³

et al. 2019

American J Phys Anthropol

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Objectives: In humans it has been shown that abrasive particles in the diet result in increased tooth wear and less intense chewing behavior, both of which decrease chewing efficiency. This behavioral response may also exist in non-human primates as a means to reduce the wear effect of dust-laden food. Here we tested whether the periodical occurrence of abrasive dust particles in the diet of Western chimpanzees affects tooth wear and reduces chewing efficiency.Materials and methods: We measured fecal particle size of undigested food matter as an indicator of chewing efficiency in 13 Western chimpanzees of the Taï National Park (Ivory Coast) before (wet), after (wet) and during a dust-rich (dry) period. Moreover, feeding data were compiled for a further 12 chimpanzees and matched to three-dimensional surface texture data measured on two molar facets of 26 skulls of the same population.Results: Fecal particles were larger during the dry period, indicating a reduced chewing efficiency compared to wet periods; age and sex did not have an effect. Concomitantly, dust led to an increase of abrasive wear evidenced by smaller texture features and higher density of fine furrows on wear facets.Discussion: Our findings show that a periodical increase in dust loads on foods places a dietaryphysiological stress on the digestive system in chimpanzees. We suggest that the impact of extrinsic abrasive particles from globally acting periodical dust-laden winds may affect evolutionary fitness. Further studies are required to elucidate this relationship in other non-human primates and fossil hominins. K E Y W O R D S abrasive particles, fecal particle size, mastication, Taï, texture

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Section: Discussionmentioning

confidence: 82%

Dust affects chewing efficiency and tooth wear in forest dwelling Western chimpanzees (Pan troglodytesverus)

Schulz‐Kornas

Stuhlträger

Clauss³

et al. 2019

American J Phys Anthropol

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“…A recent analysis of Homo naledi teeth by Towle, Irish, and De Groote () reported a high rate of antemortem chipping, more than twice that for South African hominins A. africanus and Par. robustus teeth, and much higher than those for examined extant primates.…”

Section: Introductionmentioning

confidence: 99%

“…The authors interpret this evidence to suggest that H. naledi teeth were exposed to “acute trauma” on a regular basis during life. And despite recent arguments concerning the biomechanics of chipping, Towle et al () proposed that regular consumption of grit‐laden foods, such as roots and tubers are causal, much as Robinson () suggested for Par. robustus earlier.…”

Section: Introductionmentioning

confidence: 99%

Brief communication: Dental microwear and diet of Homo naledi

Ungar

Berger

2018

American J Phys Anthropol

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“…We hypothesize that caries is likely more common than currently thought, and utilizing micro tomography (micro-CT) scans may help in getting a better understanding of the frequency of lesions in different species. Given substantial dietary differences have been suggested between the species studied (e.g., Kupczik et al, 2018;Towle et al, 2017;Henry et al, 2012;Peterson et al, 2018), we expect there will be significant differences in caries rate. The results may therefore give further information into dietary changes in the hominin lineage.…”

Section: Introductionmentioning

confidence: 83%

Dental caries in human evolution: frequency of carious lesions in South African fossil hominins

Towle

Irish

Groote

et al. 2019

Preprint

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Caries frequencies in South African fossil hominins were observed and compared with other hominin samples. Species studied include Paranthropus robustus, Homo naledi, Australopithecus africanus, early Homo and A. sediba. Teeth were viewed macroscopically with Micro-CT scans used to confirm lesions. Position and severity of each lesion were also noted and described. For all South African fossil hominin specimens studied, 16 have carious lesions, six of which are described for the first time in this study. These are from a minimum of six individuals, and include four P. robustus, one H. naledi, and one early Homo individual. No carious lesions were found on deciduous teeth, or any teeth assigned to A. africanus. Most are located interproximal, and only posterior teeth are affected. Caries frequency typically ranges between 1-5% of teeth in non-agricultural human samples, and this pattern seemingly holds true for at least the past two million years in the hominin lineage. Non-agricultural populations significantly above or below this threshold generally have a specialized diet, supporting other dietary evidence that A. africanus likely consumed large amounts of tough, non-cariogenic vegetation. Given the common occurrence of caries in the other hominin species, cariogenic bacteria and foods were evidently common in their collective oral environment. Along with recent research highlighting additional examples of caries in H. neanderthalensis, early Homo andPleistocene H. sapiens, caries is clearly an ancient disease that was much more common than once maintained throughout the course of human evolution.

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Behavioral inferences from the high levels of dental chipping in Homo naledi

Abstract: Behavioral inferences from the high levels of dental chipping in Homo naledi http://researchonline.ljmu.ac.uk/6367/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively.

Cited by 45 publications

References 56 publications

Dust affects chewing efficiency and tooth wear in forest dwelling Western chimpanzees (Pan troglodytesverus)

Dust affects chewing efficiency and tooth wear in forest dwelling Western chimpanzees (Pan troglodytesverus)

Brief communication: Dental microwear and diet of Homo naledi

Dental caries in human evolution: frequency of carious lesions in South African fossil hominins

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