Developmental defects in the teeth of three wild chimpanzees from the<scp>T</scp>aï forest

Smith, Tanya M.; Boesch, Christophe

doi:10.1002/ajpa.22741

Cited by 25 publications

(24 citation statements)

References 76 publications

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“…Developmental defects in teeth (e.g., accentuated lines and hypoplasia) are a potential indicator of seasonal (heat or rain) stress events (Guatelli‐Steinberg, ; Skinner, ; Skinner, Skinner, & Boesch, ). Such defects have been documented in tooth enamel of Taï chimpanzees (Smith & Boesch, ). Currently we do not have direct evidence from feeding observations on chimpanzees indicating such a behavioral compensatory mechanism for environmental stress, but studying tooth wear in combination with fecal particle size as a measure of chewing efficiency might be a new option of quantifying eco‐physiological stressors.…”

Section: Discussionmentioning

confidence: 83%

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: 83%

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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“…Skinner () noted that great ape canines and incisors are marked with repeated defects with regular spacing, and suggested this rhythm reflects the influence of alternating dry and rainy seasons. Other studies have tentatively linked accentuated striae to seasonal cycles, reporting a negative correlation between defect timing and rainfall abundance in Theropithecus oswaldi and common chimpanzees (Macho et al, ; Smith & Boesch, ). The proximate factors suggested to explain the regular rhythm of hypoplastic defects include seasonal variation in fruit availability, heat or water stress during dry seasons, or diseases that cycle seasonally such as malaria or hookworm (Skinner & Hopwood, ; Skinner & Pruetz, ).…”

Section: Introductionmentioning

confidence: 96%

“…Linear enamel hypoplasia is known as a nonspecific indicator of physiological perturbations during the secretory phase of amelogenesis (Goodman & Rose, ). LEH has been studied extensively across extant great apes (e.g., Guatelli‐Steinberg et al, ; Skinner & Hopwood, ; Skinner & Pruetz, ; Skinner & Skinner, ; Smith & Boesch, ), anatomically modern humans (e.g., Boyde, ; Goodman, Armelagos, & Rose, ; King, Humphrey, & Hillson, ), and other primates (e.g., Chollet & Teaford, ; Guatelli‐Steinberg, ; Newell ). Experimental and clinical studies in modern humans and other animals have established disease and/or malnutrition as causes of LEH (Goodman & Rose ).…”

Section: Introductionmentioning

confidence: 99%

“…Linear enamel hypoplasia is ubiquitous among great apes and LEH prevalence typically exceeds 75% of all individuals examined (e.g., Guatelli‐Steinberg et al, ; Skinner & Hopwood, ; Skinner & Pruetz, ; Skinner & Skinner, ; Smith & Boesch, ). However, Virunga mountain gorillas are an exception to this pattern, with prior studies reporting much lower prevalence (5–11%) (Guatelli‐Steinberg et al, ; Hannibal & Guatelli‐Steinberg, ).…”

Section: Introductionmentioning

confidence: 99%

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Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes

McGrath

El‐Zaatari

Guatelli‐Steinberg

et al. 2018

American J Phys Anthropol

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Shallow defect morphology in mountain gorillas may have led to an underestimation of LEH prevalence in past studies. Defect depth is used as a proxy for insult severity, but depth might be influenced by inter- and intra-specific variation in enamel growth. Future studies should test whether severe insults are associated with deeper defects, as might be the case with Haloko, a wild-captured gorilla. Ongoing histologic studies incorporating associated behavioral records will test possible factors that underlie differences in defect morphology.

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“…6,7 By contrast, chimpanzees from Senegal, who experience only one wet season alternating with one very long dry season, show a reconstructed average interval between repetitive episodes of enamel hypoplasia of just under a year. 9,10 The assertion that repetitive linear enamel hypoplasia (rLEH) shows an average recurrence of 6 or 12 months, is not without challengers 11,12 , but see Smith et al 13 Furthermore, linking the recurrence with semi-annual moisture cycles, which are in turn linked to metabolic stressors such as seasonal food shortages, respiratory disease, malaria or intestinal worms 8 , remains speculative. With the discovery of Homo naledi, who lived in the same geographical area as Australopithecus africanus, it becomes possible to compare temporal ontogenetic patterns of enamel hypoplasia between low-and higher-latitude hominoids.…”

Section: Introductionmentioning

confidence: 99%

Developmental stress in South African hominins: Comparison of recurrent enamel hypoplasias in Australopithecus africanus and Homo naledi

Skinner¹

2019

S. Afr. J. Sci.

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Discovery of a new hominin (Homo naledi) in the same geographical area as Australopithecus africanus creates the opportunity to compare developmental dental stress in higher latitude hominins with low that in latitude apes, among whom repetitive linear enamel hypoplasia (rLEH) recurs seasonally at about 6 or 12 months. In contrast to equatorial Africa, a single rainy/dry cycle occurs annually in non-coastal southern Africa. It is predicted that LEH will recur annually but not differ in duration between ancient and more recent hominins. Data were collected from epoxy casts of anterior teeth attributed to H. naledi (18 incisors, 13 canines) and A. africanus (29 incisors, 8 canines) using a digital microscope, surface scanner and scanning electron microscope. The location, number, width, depth and distance between defects (including perikymata counts and spatial measurements) of 136 LEH events were compared among crown moieties (deciles 4-6 and 7-9), tooth types and taxa. Enamel defects are concentrated in the cervical half of anterior crowns, and in similar numbers in each taxon. Contrary to expectations, H. naledi show bimodal LEH durations reconstructed at about 2 and 8 weeks compared to just 4 weeks in A. africanus. Both taxa show bimodally recurrent episodes of LEH centring on 2 and, more commonly and severely, 6 months. A combination of two independent annual stressor types, one disease and one seasonal, could explain the observations. These estimations of duration and recurrence of developmental stress require evaluation using actual perikymata periodicity for H. naledi and more refined understanding of palaeoenvironments for both taxa. Significance:• Seasonal stress is a central concern in the biological and health sciences. Because of the innate way that enamel is deposited, the timing of stress in the childhood of apes, modern humans and their fossil ancestors can be measured with a precision of about 1 week.• Application of this method to South African Pliocene Australopithecus africanus and Mid-Pleistocene Homo naledi reveals that, unexpectedly, both forms show semi-annual stress -a finding that is tentatively attributed to two independent annual stressors, possibly disease and malnutrition.

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Developmental defects in the teeth of three wild chimpanzees from theTaï forest

Cited by 25 publications

References 76 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)

Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes

Developmental stress in South African hominins: Comparison of recurrent enamel hypoplasias in Australopithecus africanus and Homo naledi

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