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Pampush JD, Morse PE, Kay RF. Dental sculpting and compensatory shearing crests demonstrated in a WEAR series of Presbytis rubicunda (Cercopithecoidea, Colobidae) with dental topography analysis. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 185:e24953. [PMID: 38751320 DOI: 10.1002/ajpa.24953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/28/2024] [Accepted: 04/29/2024] [Indexed: 08/15/2024]
Abstract
OBJECTIVES Maintaining effective and efficient occlusal morphology presents adaptive challenges for mammals, particularly because mastication produces interactions with foods and other materials that alters the geometry of occlusal surfaces through macrowear and/or catastrophic failure (i.e. "chipping"). Altered occlusal morphologies are often less effective for masticating materials of given diet-but not always-some species exhibit dental sculpting, meaning their dentitions are set up to harness macrowear to hone their occlusal surfaces into more effective morphologies (i.e. secondary morphologies). Here we show that dental sculpting is present in the folivorous Presbytis rubicunda of Borneo. METHODS Thirty-one undamaged lower second molars of P. rubicunda exhibiting various stages of macroscopic wear were micro-CT scanned and processed into digital surfaces. The surfaces were measured for convex Dirichlet normal energy (vDNE, a measure of surface sharpness), and degree of surface wear. Regression analyses compared surface sharpness with several measures of wear to test for the presence and magnitude of dental sculpting. RESULTS Positive correlations between the wear proxies and vDNE reveal that P. rubicunda wear in such a way as to become sharper, and therefore more effective chewing surfaces by exposing enamel-dentine junctions on their occlusal surfaces and then honing these junctions into sharpened edges. Compared to another primate folivore in which increasing surface sharpness with macrowear has been demonstrated (i.e., Alouatta palliata), the worn surfaces are similarly sharp, but the dental sculpting process appears to be different. DISCUSSION The results presented here suggest that not only do some primates exhibit dental sculpting and the attendant secondary morphology, but that there appear to be multiple different morphological configurations that can achieve this result. P. rubicunda has thicker enamel and a more stereotyped wear pattern than A. palliata, although both show positive correlations of occlusal surface sharpness (vDNE) with various wear proxies. These findings shed light on the varied approaches for the maintenance of effective and efficient occlusal surfaces in primates.
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Affiliation(s)
- James D Pampush
- Department of Health and Human Performance, High Point University, High Point, North Carolina, USA
- Department of Physician Assistant Studies, High Point University, High Point, North Carolina, USA
| | - Paul E Morse
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
- Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA
| | - Richard F Kay
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
- Division of Earth and Climate Sciences, Nicholas School, Duke University, Durham, North Carolina, USA
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Law CJ, Tinker MT, Fujii JA, Nicholson T, Staedler M, Tomoleoni JA, Young C, Mehta RS. Tool use increases mechanical foraging success and tooth health in southern sea otters ( Enhydra lutris nereis). Science 2024; 384:798-802. [PMID: 38753790 DOI: 10.1126/science.adj6608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 04/01/2024] [Indexed: 05/18/2024]
Abstract
Although tool use may enhance resource utilization, its fitness benefits are difficult to measure. By examining longitudinal data from 196 radio-tagged southern sea otters (Enhydra lutris nereis), we found that tool-using individuals, particularly females, gained access to larger and/or harder-shelled prey. These mechanical advantages translated to reduced tooth damage during food processing. We also found that tool use diminishes trade-offs between access to different prey, tooth condition, and energy intake, all of which are dependent on the relative prey availability in the environment. Tool use allowed individuals to maintain energetic requirements through the processing of alternative prey that are typically inaccessible with biting alone, suggesting that this behavior is a necessity for the survival of some otters in environments where preferred prey are depleted.
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Affiliation(s)
- Chris J Law
- Department of Biology, University of Washington, Seattle, WA, USA
- Department of Integrative Biology, University of Texas, Austin, TX, USA
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - M Tim Tinker
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- Nhydra Ecological Consulting, Halifax, Nova Scotia, Canada
- US Geological Survey, Western Ecological Research Center, Santa Cruz, CA, USA
| | | | | | | | - Joseph A Tomoleoni
- US Geological Survey, Western Ecological Research Center, Santa Cruz, CA, USA
| | - Colleen Young
- Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, Office of Spill Prevention and Response, Santa Cruz, CA, USA
| | - Rita S Mehta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, USA
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3
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Mitchell DR, Potter S, Eldridge MDB, Martin M, Weisbecker V. Functionally mediated cranial allometry evidenced in a genus of rock-wallabies. Biol Lett 2024; 20:20240045. [PMID: 38531413 PMCID: PMC10965333 DOI: 10.1098/rsbl.2024.0045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 03/04/2024] [Indexed: 03/28/2024] Open
Abstract
In assessments of skeletal variation, allometry (disproportionate change of shape with size) is often corrected to examine size-independent variation for hypotheses relating to function. However, size-related trade-offs in functional demands may themselves be an underestimated driver of mammalian cranial diversity. Here, we use geometric morphometrics alongside dental measurements to assess craniodental allometry in the rock-wallaby genus Petrogale (all 17 species, 370 individuals). We identified functional aspects of evolutionary allometry that can be both extensions of, and correlated negatively with, static or ontogenetic allometric patterns. Regarding constraints, larger species tended to have relatively smaller braincases and more posterior orbits, the former of which might represent a constraint on jaw muscle anatomy. However, they also tended to have more anterior dentition and smaller posterior zygomatic arches, both of which support the hypothesis of relaxed bite force demands and accommodation of different selective pressures that favour facial elongation. By contrast, two dwarf species had stouter crania with divergent dental adaptations that together suggest increased relative bite force capacity. This likely allows them to feed on forage that is mechanically similar to that consumed by larger relatives. Our results highlight a need for nuanced considerations of allometric patterns in future research of mammalian cranial diversity.
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Affiliation(s)
- D. Rex Mitchell
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales 2522, Australia
| | - Sally Potter
- School of Natural Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
- Australian Museum Research Institute, Sydney, New South Wales 2010, Australia
| | - Mark D. B. Eldridge
- Australian Museum Research Institute, Sydney, New South Wales 2010, Australia
| | - Meg Martin
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Vera Weisbecker
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales 2522, Australia
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4
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Sender RS, Strait DS. The biomechanics of tooth strength: testing the utility of simple models for predicting fracture in geometrically complex teeth. J R Soc Interface 2023; 20:20230195. [PMID: 37376873 PMCID: PMC10300505 DOI: 10.1098/rsif.2023.0195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
Teeth must fracture foods while avoiding being fractured themselves. This study evaluated dome biomechanical models used to describe tooth strength. Finite-element analysis (FEA) tested whether the predictions of the dome models applied to the complex geometry of an actual tooth. A finite-element model was built from microCT scans of a human M3. The FEA included three loading regimes simulating contact between (i) a hard object and a single cusp tip, (ii) a hard object and all major cusp tips and (iii) a soft object and the entire occlusal basin. Our results corroborate the dome models with respect to the distribution and orientation of tensile stresses, but document heterogeneity of stress orientation across the lateral enamel. This implies that high stresses might not cause fractures to fully propagate between cusp tip and cervix under certain loading conditions. The crown is most at risk of failing during hard object biting on a single cusp. Geometrically simple biomechanical models are valuable tools for understanding tooth function but do not fully capture aspects of biomechanical performance in actual teeth whose complex geometries may reflect adaptations for strength.
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Affiliation(s)
- Rachel S. Sender
- Department of Anthropology, Washington University in St Louis, St Louis, MO 63013, USA
| | - David S. Strait
- Department of Anthropology, Washington University in St Louis, St Louis, MO 63013, USA
- Paleo-Research Institute, University of Johannesburg, Auckland Park, Gauteng 2092, South Africa
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5
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Guatelli-Steinberg D, Schwartz GT, O'Hara MC, Gurian K, Rychel J, Dunham N, Cunneyworth PMK, Donaldson A, McGraw WS. Aspects of molar form and dietary proclivities of African colobines. J Hum Evol 2023; 180:103384. [PMID: 37201412 DOI: 10.1016/j.jhevol.2023.103384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 04/04/2023] [Accepted: 04/09/2023] [Indexed: 05/20/2023]
Abstract
This study investigates aspects of molar form in three African colobine species: Colobus polykomos, Colobus angolensis, and Piliocolobus badius. Our samples of C. polykomos and P. badius are from the Taï Forest, Ivory Coast; our sample of C. angolensis is from Diani, Kenya. To the extent that protective layers surrounding seeds are hard, we predicted that molar features related to hard-object feeding would be more pronounced in Colobus than they are Piliocolobus, as seed-eating generally occurs at higher frequencies in species of the former. We further predicted that among the colobines we studied, these features would be most pronounced in Taï Forest C. polykomos, which feeds on Pentaclethra macrophylla seeds encased within hard and tough seed pods. We compared overall enamel thickness, enamel thickness distribution, absolute crown strength, cusp tip geometry, and flare among molar samples. Sample sizes per species and molar type varied per comparison. We predicted differences in all variables except overall enamel thickness, which we expected would be invariant among colobines as a result of selection for thin enamel in these folivorous species. Of the variables we examined, only molar flare differed significantly between Colobus and Piliocolobus. Our findings suggest that molar flare, an ancient feature of cercopithecoid molars, was retained in Colobus but not in Piliocolobus, perhaps as a result of differences in the seed-eating proclivities of the two genera. Contrary to predictions, none of the aspects of molar form we investigated tracked current dietary differences in seed-eating between the two Colobus species. Finally, we explored the possibility that molar flare and absolute crown strength, when analyzed together, might afford greater differentiation among these colobine species. A multivariate t test of molar flare and absolute crown strength differentiated C. polykomos and P. badius, possibly reflecting known niche divergence between these two sympatric Taï Forest species.
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Affiliation(s)
- Debbie Guatelli-Steinberg
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA; School of Anthropology and Conservation, University of Kent, Canterbury, Kent, CT2 7NR, UK.
| | - Gary T Schwartz
- Institute of Human Origins & School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, 85287, USA
| | - Mackie C O'Hara
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA; School of Anthropology and Conservation, University of Kent, Canterbury, Kent, CT2 7NR, UK
| | - Kaita Gurian
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA
| | - Jess Rychel
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA
| | - Noah Dunham
- Division of Conservation and Science, Cleveland Metroparks Zoo, 4200 Wildlife Way, Cleveland, OH, 44109, USA; Department of Biology, Case Western Reserve University, 2080 Adelbert Road, Cleveland, OH, 44106, USA
| | | | - Andrea Donaldson
- Colobus Conservation, P.O. Box 5380-80401, Diani, Kenya; Department of Anthropology, Durham University, Durham, DH1 3LE, UK
| | - W Scott McGraw
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA
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6
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Fannin LD, Swedell L, McGraw WS. Enamel chipping and its ecological correlates in African papionins: Implications for hominin feeding behavior. J Hum Evol 2023; 177:103330. [PMID: 36898301 DOI: 10.1016/j.jhevol.2023.103330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 03/12/2023]
Abstract
African papionins are classic paleoecological referents for fossil hominins. Enamel chips on the teeth of baboons and hominins are argued to represent responses to similar dietary habits; however, a comprehensive analysis of modern papionin chipping is lacking, leaving open the question of analog suitability. Here, we investigate patterns of antemortem enamel chipping across a diverse set of African papionin species occupying a range of ecological niches. We compare papionin chipping frequencies to estimates for Plio-Pleistocene hominins to address hypotheses of habitat and/or dietary similarities. Antemortem chips in seven African papionin species were scored on intact postcanine teeth (P3-M3) using established protocols. Chip size was scored on a tripartite scale. Papio hamadryas and Papio ursinus-two common paleoecological referents-display higher levels of chipping than Plio-Pleistocene hominin taxa (Australopithecus and Paranthropus) posited to have similar dietary habits. Papio populations occupying dry or highly seasonal habitats accumulate more large chips than Papio taxa occupying more mesic habitats, and terrestrial papionins chip their teeth more often than closely related taxa occupying arboreal niches. Chipping is present on the teeth of all Plio-Pleistocene hominins; however, chipping in baboons (P. ursinus and P. hamadryas) consistently exceeds most hominin taxa. Chipping frequencies on their own do not reliably sort taxa into major dietary groupings. We conclude that the large differences in chipping frequency may instead reflect habitat use and food processing idiosyncrasies. Less chipping in Plio-Pleistocene hominin teeth compared to modern Papio is more likely attributable to differences in dental morphology rather than diet.
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Affiliation(s)
- Luke D Fannin
- Department of Anthropology, Dartmouth College, Hanover, NH, 03755, USA; Graduate Program in Ecology, Evolution, Environment, and Society, Dartmouth College, Hanover, NH, 03755, USA.
| | - Larissa Swedell
- Department of Anthropology, Queens College, City University of New York, Flushing, NY, 11367, USA; Anthropology Program, Graduate Center, City University of New York, New York, NY, 10016, USA; New York Consortium in Evolutionary Primatology, New York, NY, 10016, USA; Department of Archaeology, University of Cape Town, Rondebosch, Western Cape, 7700, South Africa
| | - W Scott McGraw
- Department of Anthropology, The Ohio State University, Columbus, OH, 43210, USA
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7
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Soukup JW, Jeffery J, Hetzel SJ, Ploeg HL, Henak CR. Morphological quantification of the maxillary canine tooth in the domestic dog (Canis lupus familiaris). Ann Anat 2023; 246:152041. [PMID: 36526093 PMCID: PMC9947742 DOI: 10.1016/j.aanat.2022.152041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/20/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
Canine tooth shape is known to vary with diet and killing behavior in wild animals and the relationship between form and function is driven in part by selective pressure. However, comparative investigation of the domestic dog (Canis lupus familiaris) is of interest. How do they compare to their wild counterparts? This study sought to quantify and characterize the morphology of the canine tooth in the domestic dog, and to provide a preliminary investigation into the variance in canine tooth morphology across individual dogs of varying breeds. Three-dimensional (3D) models generated from micro-computed tomography (µ-CT) studies of 10 mature maxillary canine teeth from the domesticated dog (Canis lupus familiaris) were used to quantify key morphological features and evaluate variance among dogs. Results show that, utilizing modern imaging and model building software, the morphology of the canine tooth can be comprehensively characterized and quantified. Morphological variables such as second moment of area and section modulus (geometrical parameters related to resistance to bending), as well as aspect ratio, ridge sharpness, cusp sharpness and enamel thickness are optimized in biomechanically critical areas of the tooth crown to balance form and function. Tooth diameter, second moment of area, section modulus, cross sectional area, tooth volume and length as well as enamel thickness are highly correlated with body weight. In addition, we found preliminary evidence of morphological variance across individual dogs. Quantification of these features provide insight into the balance of form and function of the canine tooth in wild and domesticated canids. In addition, results suggest that variance between dogs exist in some morphological features and most morphological features are highly correlated with body weight.
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Affiliation(s)
- Jason W Soukup
- Department of Surgical Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA.
| | - Justin Jeffery
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Scott J Hetzel
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Heidi-Lynn Ploeg
- Department of Mechanics and Materials Engineering, Queen's University, Kingston, ON, Canada
| | - Corinne R Henak
- Department of Mechanical Engineering, University of Wisconsin-Madison, College of Engineering, Madison, WI, USA; Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
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Guatelli‐Steinberg D, Schwartz GT, O'Hara MC, Gurian K, Rychel J, McGraw WS. Molar form, enamel growth, and durophagy in Cercocebus and Lophocebus. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 179:386-404. [PMCID: PMC9796247 DOI: 10.1002/ajpa.24592] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 06/20/2022] [Accepted: 06/29/2022] [Indexed: 05/29/2023]
Abstract
Objectives To test the hypothesis that differences in crown structure, enamel growth, and crown geometry in Cercocebus and Lophocebus molars covary with differences in the feeding strategies (habitual vs. fallback durophagy, respectively) of these two genera. Relative to Lophocebus molars, Cercocebus molars are predicted to possess features associated with greater fracture resistance and to differ in enamel growth parameters related to these features. Materials and Methods Sample proveniences are as follows: Cercocebus atys molars are from the Taï Forest, Ivory Coast; Lophocebus albigena molars are from a site north of Makoua, Republic of Congo; and a Lophocebus atterimus molar is from the Lomako Forest, Democratic Republic of Congo. For μCT scans on which aspects of molar form were measured, sample sizes ranged from 5 to 35 for Cercocebus and 3 to 12 for Lophocebus. A subsample of upper molars was physically sectioned to measure enamel growth variables. Results Partly as a function of their larger size, Cercocebus molars had significantly greater absolute crown strength (ACS) than Lophocebus molars, supporting the hypothesis. Greater crown heights in Cercocebus are achieved through faster enamel extension rates. Also supporting the hypothesis, molar flare and proportional occlusal basin enamel thickness were significantly greater in Cercocebus. Relative enamel thickness (RET), however, was significantly greater in Lophocebus. Discussion If ACS is a better predictor of fracture resistance than RET, then Cercocebus molars may be more fracture resistant than those of Lophocebus. Greater molar flare and proportional occlusal basin thickness might also afford Cercocebus molars greater fracture resistance.
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Affiliation(s)
| | - Gary T. Schwartz
- School of Human Evolution and Social Change and Institute of Human OriginsArizona State UniversityTempeArizonaUSA
| | - Mackie C. O'Hara
- Department of AnthropologyThe Ohio State UniversityColumbusOhioUSA
- School of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Kaita Gurian
- Department of AnthropologyThe Ohio State UniversityColumbusOhioUSA
| | - Jess Rychel
- Department of AnthropologyThe Ohio State UniversityColumbusOhioUSA
| | - W. Scott McGraw
- Department of AnthropologyThe Ohio State UniversityColumbusOhioUSA
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Winkler DE, Clauss M, Kubo MO, Schulz-Kornas E, Kaiser TM, Tschudin A, De Cuyper A, Kubo T, Tütken T. Microwear textures associated with experimental near-natural diets suggest that seeds and hard insect body parts cause high enamel surface complexity in small mammals. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.957427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In mammals, complex dental microwear textures (DMT) representing differently sized and shaped enamel lesions overlaying each other have traditionally been associated with the seeds and kernels in frugivorous diets, as well as with sclerotized insect cuticles. Recently, this notion has been challenged by field observations as well as in vitro experimental data. It remains unclear to what extent each food item contributes to the complexity level and is reflected by the surface texture of the respective tooth position along the molar tooth row. To clarify the potential of seeds and other abrasive dietary items to cause complex microwear textures, we conducted a controlled feeding experiment with rats. Six individual rats each received either a vegetable mix, a fruit mix, a seed mix, whole crickets, whole black soldier fly larvae, or whole day-old-chicks. These diets were subjected to material testing to obtain mechanical properties, such as Young’s modulus, yield strength, and food hardness (as indicated by texture profile analysis [TPA] tests). Seeds and crickets caused the highest surface complexity. The fruit mix, seed mix, and crickets caused the deepest wear features. Moreover, several diets resulted in an increasing wear gradient from the first to the second molar, suggesting that increasing bite force along the tooth row affects dental wear in rats on these diets. Mechanical properties of the diets showed different correlations with DMT obtained for the first and second molars. The first molar wear was mostly correlated with maximum TPA hardness, while the second molar wear was strongly correlated with maximum yield stress, mean TPA hardness, and maximum TPA hardness. This indicates a complex relationship between chewing mechanics, food mechanical properties, and observed DMT. Our results show that, in rats, seeds are the main cause of complex microwear textures but that hard insect body parts can also cause high complexity. However, the similarity in parameter values of surface textures resulting from seed and cricket consumption did not allow differentiation between these two diets in our experimental approach.
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van Casteren A, Codd JR, Kupczik K, Plasqui G, Sellers WI, Henry AG. The cost of chewing: The energetics and evolutionary significance of mastication in humans. SCIENCE ADVANCES 2022; 8:eabn8351. [PMID: 35977013 PMCID: PMC9385136 DOI: 10.1126/sciadv.abn8351] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Any change in the energetic cost of mammalian mastication will affect the net energy gain from foods. Although the energetic efficiency of masticatory effort is fundamental in understanding the evolution of the human masticatory system, nothing is known currently about the associated metabolic costs of chewing different items. Here, using respirometry and electromyography of the masseter muscle, we demonstrate that chewing by human subjects represents a measurable energy sink. Chewing a tasteless odorless gum elevates metabolic rate by 10 to 15% above basal levels. Energy expenditure increases with gum stiffness and is paid for by greater muscle recruitment. For modern humans, it is likely that mastication represents a small part of the daily energy budget. However, for our ancestors, before the onset of cooking and sophisticated food processing methods, the costs must have been relatively high, adding a previously unexplored energetic dimension to the interpretation of hominin dentofacial fossils.
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Affiliation(s)
- Adam van Casteren
- School of Biological Sciences, University of Manchester, Manchester, UK
- Max Planck Weizmann Center for Evolutionary Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Corresponding author.
| | - Jonathan R. Codd
- School of Biological Sciences, University of Manchester, Manchester, UK
| | - Kornelius Kupczik
- Max Planck Weizmann Center for Evolutionary Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Anthropology, Faculty of Social Sciences, University of Chile, Santiago de Chile, Chile
| | - Guy Plasqui
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands
| | | | - Amanda G. Henry
- Faculty of Archaeology, Leiden University, Leiden, Netherlands
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11
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Sign-oriented Dirichlet Normal Energy: Aligning Dental Topography and Dental Function in the R-package molaR. J MAMM EVOL 2022. [DOI: 10.1007/s10914-022-09616-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Berthaume MA, Kupczik K. Molar biomechanical function in South African hominins Australopithecus africanus and Paranthropus robustus. Interface Focus 2021; 11:20200085. [PMID: 34938434 DOI: 10.1098/rsfs.2020.0085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2021] [Indexed: 11/12/2022] Open
Abstract
Diet is a driving force in human evolution. Two species of Plio-Pleistocene hominins, Paranthropus robustus and Australopithecus africanus, have derived craniomandibular and dental morphologies which are often interpreted as P. robustus having a more biomechanically challenging diet. While dietary reconstructions based on dental microwear generally support this, they show extensive dietary overlap between species, and craniomandibular and dental biomechanical analyses can yield contradictory results. Using methods from anthropology and engineering (i.e. anthroengineering), we quantified the molar biomechanical performance of these hominins to investigate possible dietary differences between them. Thirty-one lower second molars were 3D printed and used to fracture gelatine blocks, and Bayesian generalized linear models were used to investigate the relationship between species and tooth wear, size and shape, and biomechanical performance. Our results demonstrate that P. robustus required more force and energy to fracture blocks but had a higher force transmission rate. Considering previous dietary reconstructions, we propose three evolutionary scenarios concerning the dietary ecologies of these hominins. These evolutionary scenarios cannot be reached by investigating morphological differences in isolation, but require combining several lines of evidence. This highlights the need for a holistic approach to reconstructing hominin dietary ecology.
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Affiliation(s)
- Michael A Berthaume
- Division of Mechanical Engineering and Design, London South Bank University, 103 Borough Road, London SE1 0AA, UK.,Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute of Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Kornelius Kupczik
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute of Evolutionary Anthropology, 04103 Leipzig, Germany.,Department of Human Evolution, Max Planck Institute of Evolutionary Anthropology, 04103 Leipzig, Germany
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Dental chipping supports lack of hard-object feeding in Paranthropus boisei. J Hum Evol 2021; 156:103015. [PMID: 34038770 DOI: 10.1016/j.jhevol.2021.103015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 02/06/2023]
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14
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Chipping and wear patterns in extant primate and fossil hominin molars: 'Functional' cusps are associated with extensive wear but low levels of fracture. J Hum Evol 2020; 151:102923. [PMID: 33360110 DOI: 10.1016/j.jhevol.2020.102923] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 01/01/2023]
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15
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Yi Z, Liao W, Zanolli C, Wang W. A robust alternative to assessing three-dimensional relative enamel thickness for the use in taxonomic assessment. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 174:555-567. [PMID: 33247444 DOI: 10.1002/ajpa.24187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 10/18/2020] [Accepted: 11/04/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Three-dimensional relative enamel thickness (3DRET) is important for assessing hypotheses about taxonomy, phylogeny, and dietary reconstruction for primates. However, its weaknesses have not been thoroughly investigated. Here, we analyze its weaknesses and propose an index aiming at better taxonomic discrimination. MATERIALS AND METHODS The dimensionless 3D index, ratio of enamel-thickness to dentine-thickness (3DRED), which is defined as the cubic root of the ratio of 3D average enamel thickness (3DAET) to 3D average dentine thickness (3DADT), is proposed here. To compare 3DRET and 3DRED and their sensitivity to voxel size, a fossil orangutan molar was scanned 14 times with different resolutions ranging from 10 to 50 μm. Enamel thickness analysis was carried out for each resultant digital model. In addition, enamel thickness measurements of 179 mandibular permanent molars (eight genera) were analyzed, followed by investigating the relationship between 3DRET and 3DAET and between 3DRED and 3DAET. RESULTS Regarding sensitivity, 3DRED is more robust than 3DRET. In addition, 3DRET is correlated with 3DAET by linear curve with regression coefficients approximating or larger than 0.8 in most cases, while 3DRED shows less correlation with 3DAET. Furthermore, there are clear separations between different taxa in the bivariate plot of 3DRED against 3DAET, indicative of the taxonomic value of 3DRED. CONCLUSION Under certain conditions, 3DRED promises to be a robust and reliable alternative to 3DRET in taxonomic study.
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Affiliation(s)
- Zhixing Yi
- School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Wei Liao
- School of Earth Sciences, China University of Geosciences, Wuhan, China.,Anthropology Museum of Guangxi, Nanning, China
| | - Clément Zanolli
- Laboratoire PACEA, UMR 5199 CNRS, Université de Bordeaux, Pessac, France
| | - Wei Wang
- Anthropology Museum of Guangxi, Nanning, China.,Institute of Cultural Heritage, Shandong University, Qingdao, China
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16
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Lockey AL, Alemseged Z, Hublin JJ, Skinner MM. Maxillary molar enamel thickness of Plio-Pleistocene hominins. J Hum Evol 2020; 142:102731. [DOI: 10.1016/j.jhevol.2019.102731] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 11/19/2019] [Accepted: 12/02/2019] [Indexed: 11/30/2022]
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17
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Schwartz GT, McGrosky A, Strait DS. Fracture mechanics, enamel thickness and the evolution of molar form in hominins. Biol Lett 2020; 16:20190671. [PMID: 31964261 DOI: 10.1098/rsbl.2019.0671] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
As the tissue most directly responsible for breaking down food in the oral cavity, the form and function of enamel is obviously of evolutionary significance in humans, non-human primates and other vertebrates. Accordingly, a standard metric, relative enamel thickness (RET), has been used for many decades to provide insights into vertebrate and human palaeobiology. Relatively thick enamel has evolved many times in vertebrates including hominoids (the group to which living humans and fossil hominins belong), and this pattern is thought to provide information about taxonomy, phylogeny, functional anatomy and diet. In particular, relatively thick enamel is thought to make tooth crowns strong so that they resist fractures associated with eating mechanically resistant foods. Here, we use current models of tooth biomechanics to show that RET is at best only moderately informative of function and diet in living hominoids and fossil hominins, and at worst provides misleading information. We propose a new metric, absolute crown strength, to assess the resistance of teeth to fracture, and identify what may be a novel characteristic of tooth strength in fossil hominins.
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Affiliation(s)
- Gary T Schwartz
- Institute of Human Origins, Arizona State University, Tempe, AZ, USA.,School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA
| | - Amanda McGrosky
- Institute of Human Origins, Arizona State University, Tempe, AZ, USA.,School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA
| | - David S Strait
- Department of Anthropology, Washington University in St Louis, St Louis, MO, USA.,Palaeo-Research Institute, University of Johannesburg, Gauteng, South Africa
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18
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van Casteren A, Strait DS, Swain MV, Michael S, Thai LA, Philip SM, Saji S, Al-Fadhalah K, Almusallam AS, Shekeban A, McGraw WS, Kane EE, Wright BW, Lucas PW. Hard plant tissues do not contribute meaningfully to dental microwear: evolutionary implications. Sci Rep 2020; 10:582. [PMID: 31953510 PMCID: PMC6969033 DOI: 10.1038/s41598-019-57403-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 12/27/2019] [Indexed: 11/09/2022] Open
Abstract
Reconstructing diet is critical to understanding hominin adaptations. Isotopic and functional morphological analyses of early hominins are compatible with consumption of hard foods, such as mechanically-protected seeds, but dental microwear analyses are not. The protective shells surrounding seeds are thought to induce complex enamel surface textures characterized by heavy pitting, but these are absent on the teeth of most early hominins. Here we report nanowear experiments showing that the hardest woody shells - the hardest tissues made by dicotyledonous plants - cause very minor damage to enamel but are themselves heavily abraded (worn) in the process. Thus, hard plant tissues do not regularly create pits on enamel surfaces despite high forces clearly being associated with their oral processing. We conclude that hard plant tissues barely influence microwear textures and the exploitation of seeds from graminoid plants such as grasses and sedges could have formed a critical element in the dietary ecology of hominins.
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Affiliation(s)
- Adam van Casteren
- Department of Anthropology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - David S Strait
- Department of Anthropology, Washington University in St. Louis, St. Louis, MO, 63130, USA.,Palaeo-Research Institute, University of Johannesburg, Auckland Park, Gauteng, South Africa
| | - Michael V Swain
- Department of Bioengineering, Don State Technical University, Rostov-on-Don, Russia
| | - Shaji Michael
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait
| | - Lidia A Thai
- Department of Mechanical Engineering, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat, 13060, Kuwait
| | - Swapna M Philip
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait
| | - Sreeja Saji
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait
| | - Khaled Al-Fadhalah
- Department of Mechanical Engineering, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat, 13060, Kuwait
| | - Abdulwahab S Almusallam
- Department of Chemical Engineering, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat, 13060, Kuwait
| | - Ali Shekeban
- Department of Mechanical Engineering, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat, 13060, Kuwait
| | - W Scott McGraw
- Department of Anthropology, 4064 Smith Laboratory, The Ohio State University, 174 West 18th Ave., Columbus, OH, 43210-1106, USA
| | - Erin E Kane
- Department of Anthropology, Boston University, 232 Bay State Rd, Boston, MA02215-1403, USA
| | - Barth W Wright
- College of Osteopathic Medicine, Kansas City University of Medicine and Biosciences, 1750 Independence Ave., Kansas City, MO, 64106, USA
| | - Peter W Lucas
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait.,Smithsonian Tropical Research Institute, Apartado Postal, 0843-03092, Panamá, República de Panamá
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19
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Mitchell DR. The anatomy of a crushing bite: The specialised cranial mechanics of a giant extinct kangaroo. PLoS One 2019; 14:e0221287. [PMID: 31509570 PMCID: PMC6738596 DOI: 10.1371/journal.pone.0221287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 08/02/2019] [Indexed: 11/28/2022] Open
Abstract
The Sthenurinae were a diverse subfamily of short-faced kangaroos that arose in the Miocene and diversified during the Pliocene and Pleistocene. Many species possessed skull morphologies that were relatively structurally reinforced with bone, suggesting that they were adapted to incorporate particularly resistant foods into their diets. However, the functional roles of many unique, robust features of the sthenurine cranium are not yet clearly defined. Here, the finite element method is applied to conduct a comprehensive analysis of unilateral biting along the cheek tooth battery of a well-represented sthenurine, Simosthenurus occidentalis. The results are compared with those of an extant species considered to be of most similar ecology and cranial proportions to this species, the koala (Phascolarctos cinereus). The simulations reveal that the cranium of S. occidentalis could produce and withstand comparatively high forces during unilateral biting. Its greatly expanded zygomatic arches potentially housed enlarged zygomaticomandibularis muscles, shown here to reduce the risk of dislocation of the temporomandibular joint during biting with the rear of a broad, extensive cheek tooth row. This may also be a function of the zygomaticomandibularis in the giant panda (Ailuropoda melanoleuca), another species known to exhibit an enlarged zygomatic arch and hypertrophy of this muscle. Furthermore, the expanded frontal plates of the S. occidentalis cranium form broad arches of bone with the braincase and deepened maxillae that each extend from the anterior tooth rows to their opposing jaw joints. These arches are demonstrated here to be a key feature in resisting high torsional forces during unilateral premolar biting on large, resistant food items. This supports the notion that S. occidentalis fed thick, lignified vegetation directly to the cheek teeth in a similar manner to that described for the giant panda when crushing mature bamboo culms.
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Affiliation(s)
- D. Rex Mitchell
- Zoology Division, School of Environmental and Rural Sciences, University of New England, Armidale, New South Wales, Australia
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, United States of America
- * E-mail:
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20
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Law CJ, Mehta RS. Dry versus wet and gross: Comparisons between the dry skull method and gross dissection in estimations of jaw muscle cross-sectional area and bite forces in sea otters. J Morphol 2019; 280:1706-1713. [PMID: 31513299 DOI: 10.1002/jmor.21061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/24/2019] [Accepted: 08/13/2019] [Indexed: 02/05/2023]
Abstract
Bite force is a measure of feeding performance used to elucidate links between animal morphology, ecology, and fitness. Obtaining live individuals for in vivo bite-force measurements or freshly deceased specimens for bite force modeling is challenging for many species. Thomason's dry skull method for mammals relies solely on osteological specimens and, therefore, presents an advantageous approach that enables researchers to estimate and compare bite forces across extant and even extinct species. However, how accurately the dry skull method estimates physiological cross-sectional area (PCSA) of the jaw adductor muscles and theoretical bite force has rarely been tested. Here, we use an ontogenetic series of southern sea otters (Enhydra lutris nereis) to test the hypothesis that skeletomuscular traits estimated from the dry skull method accurately predicts test traits derived from dissection-based biomechanical modeling. Although variables from these two methods exhibited strong positive relationships across ontogeny, we found that the dry skull method overestimates PCSA of the masseter and underestimates PCSA of the temporalis. Jaw adductor in-levers for both jaw muscles and overall bite force are overestimated. Surprisingly, we reveal that sexual dimorphism in craniomandibular shape affects temporalis PCSA estimations; the dry skull method predicted female temporalis PCSA well but underestimates male temporalis PCSA across ontogeny. These results highlight the importance of accounting for sexual dimorphism and other intraspecific variation when using the dry skull method. Together, we found the dry skull method provides an underestimation of bite force over ontogeny and that the underlying anatomical components driving bite force may be misrepresented.
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Affiliation(s)
- Chris J Law
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California
| | - Rita S Mehta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California
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21
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Hartstone‐Rose A, Hertzig I, Dickinson E. Bite Force and Masticatory Muscle Architecture Adaptations in the Dietarily Diverse Musteloidea (Carnivora). Anat Rec (Hoboken) 2019; 302:2287-2299. [DOI: 10.1002/ar.24233] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Adam Hartstone‐Rose
- Department of Biological Sciences North Carolina State University Raleigh North Carolina
| | - Isabella Hertzig
- Department of Biological Sciences North Carolina State University Raleigh North Carolina
| | - Edwin Dickinson
- Department of Biological Sciences North Carolina State University Raleigh North Carolina
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22
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Seasonal and habitat effects on the nutritional properties of savanna vegetation: Potential implications for early hominin dietary ecology. J Hum Evol 2019; 133:99-107. [DOI: 10.1016/j.jhevol.2019.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/09/2019] [Accepted: 01/23/2019] [Indexed: 11/22/2022]
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23
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Burrows AM, Nash LT, Hartstone‐Rose A, Silcox MT, López‐Torres S, Selig KR. Dental Signatures for Exudativory in Living Primates, with Comparisons to Other Gouging Mammals. Anat Rec (Hoboken) 2019; 303:265-281. [DOI: 10.1002/ar.24048] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/03/2018] [Accepted: 06/11/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Anne M. Burrows
- Department of Physical TherapyDuquesne University Pittsburgh Pennsylvania
- Department of AnthropologyUniversity of Pittsburgh Pittsburgh Pennsylvania
| | - Leanne T. Nash
- School of Human Evolution and Social ChangeArizona State University Tempe Arizona
| | | | - Mary T. Silcox
- Department of AnthropologyUniversity of Toronto Scarborough Toronto Canada
| | - Sergi López‐Torres
- Department of Evolutionary PaleobiologyRoman Kozłowski Institute of Paleobiology, Polish Academy of Sciences Warsaw Poland
| | - Keegan R. Selig
- Department of AnthropologyUniversity of Toronto Scarborough Toronto Canada
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24
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Law CJ, Duran E, Hung N, Richards E, Santillan I, Mehta RS. Effects of diet on cranial morphology and biting ability in musteloid mammals. J Evol Biol 2018; 31:1918-1931. [DOI: 10.1111/jeb.13385] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 09/23/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Chris J. Law
- Department of Ecology and Evolutionary Biology Coastal Biology Building University of California, Santa Cruz Santa Cruz CA USA
| | - Emma Duran
- Scotts Valley High School Scotts Valley CA USA
| | - Nancy Hung
- Massachusetts Institute of Technology Cambridge MA USA
| | - Ekai Richards
- Department of Ecology and Evolutionary Biology Coastal Biology Building University of California, Santa Cruz Santa Cruz CA USA
| | | | - Rita S. Mehta
- Department of Ecology and Evolutionary Biology Coastal Biology Building University of California, Santa Cruz Santa Cruz CA USA
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25
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Constantino PJ, Borrero‐Lopez O, Lawn BR. Mechanisms of tooth damage and
Paranthropus
dietary reconstruction. BIOSURFACE AND BIOTRIBOLOGY 2018. [DOI: 10.1049/bsbt.2018.0017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
| | - Oscar Borrero‐Lopez
- Departamento de Ingeniería Mecánica, Energética y de los MaterialesUniversidad de Extremadura06006BadajozSpain
| | - Brian R. Lawn
- Materials Measurement LaboratoryNational Institute of Standards and TechnologyGaithersburgMD20899USA
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26
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Crane RL, Cox SM, Kisare SA, Patek SN. Smashing mantis shrimp strategically impact shells. ACTA ACUST UNITED AC 2018; 221:221/11/jeb176099. [PMID: 29903746 DOI: 10.1242/jeb.176099] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/16/2018] [Indexed: 12/15/2022]
Abstract
Many predators fracture strong mollusk shells, requiring specialized weaponry and behaviors. The current shell fracture paradigm is based on jaw- and claw-based predators that slowly apply forces (high impulse, low peak force). However, predators also strike shells with transient intense impacts (low impulse, high peak force). Toward the goal of incorporating impact fracture strategies into the prevailing paradigm, we measured how mantis shrimp (Neogonodactylus bredini) impact snail shells, tested whether they strike shells in different locations depending on prey shape (Nerita spp., Cenchritis muricatus, Cerithium spp.) and deployed a physical model (Ninjabot) to test the effectiveness of strike locations. We found that, contrary to their formidable reputation, mantis shrimp struck shells tens to hundreds of times while targeting distinct shell locations. They consistently struck the aperture of globular shells and changed from the aperture to the apex of high-spired shells. Ninjabot tests revealed that mantis shrimp avoid strike locations that cause little damage and that reaching the threshold for eating soft tissue is increasingly difficult as fracture progresses. Their ballistic strategy requires feed-forward control, relying on extensive pre-strike set-up, unlike jaw- and claw-based strategies that can use real-time neural feedback when crushing. However, alongside this pre-processing cost to impact fracture comes the ability to circumvent gape limits and thus process larger prey. In sum, mantis shrimp target specific shell regions, alter their strategy depending on shell shape, and present a model system for studying the physics and materials of impact fracture in the context of the rich evolutionary history of predator-prey interactions.
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Affiliation(s)
- R L Crane
- Biology Department, Duke University, Durham, NC 27708-0338, USA
| | - S M Cox
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003-9316, USA
| | - S A Kisare
- Biology Department, Duke University, Durham, NC 27708-0338, USA
| | - S N Patek
- Biology Department, Duke University, Durham, NC 27708-0338, USA
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27
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Paine OC, Koppa A, Henry AG, Leichliter JN, Codron D, Codron J, Lambert JE, Sponheimer M. Grass leaves as potential hominin dietary resources. J Hum Evol 2018; 117:44-52. [DOI: 10.1016/j.jhevol.2017.10.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 11/30/2022]
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28
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Constantino PJ, Bush MB, Barani A, Lawn BR. On the evolutionary advantage of multi-cusped teeth. J R Soc Interface 2017; 13:rsif.2016.0374. [PMID: 27558851 DOI: 10.1098/rsif.2016.0374] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/28/2016] [Indexed: 11/12/2022] Open
Abstract
A hallmark of mammalian evolution is a progressive complexity in postcanine tooth morphology. However, the driving force for this complexity remains unclear: whether to expand the versatility in diet source, or to bolster tooth structural integrity. In this study, we take a quantitative approach to this question by examining the roles of number, position and height of multiple cusps in determining sustainable bite forces. Our approach is to use an extended finite-element methodology with due provision for step-by-step growth of an embedded crack to determine how fracture progresses with increasing occlusal load. We argue that multi-cusp postcanine teeth are well configured to withstand high bite forces provided that multiple cusps are contacted simultaneously to share the load. However, contact on a single near-wall cusp diminishes the strength. Location of the load points and cusp height, rather than cusp number or radius, are principal governing factors. Given these findings, we conclude that while complex tooth structures can enhance durability, increases in cusp number are more likely to be driven by the demands of food manipulation. Structural integrity of complex teeth is maintained when individual cusps remain sufficiently distant from the side walls and do not become excessively tall relative to tooth width.
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Affiliation(s)
- Paul J Constantino
- Department of Biology, Saint Michael's College, Colchester, VT 05439, USA
| | - Mark B Bush
- School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Amir Barani
- School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Brian R Lawn
- Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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29
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Campbell KM, Santana SE. Do differences in skull morphology and bite performance explain dietary specialization in sea otters? J Mammal 2017. [DOI: 10.1093/jmammal/gyx091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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30
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Thiery G, Lazzari V, Ramdarshan A, Guy F. Beyond the Map: Enamel Distribution Characterized from 3D Dental Topography. Front Physiol 2017; 8:524. [PMID: 28785226 PMCID: PMC5519568 DOI: 10.3389/fphys.2017.00524] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/07/2017] [Indexed: 11/24/2022] Open
Abstract
Enamel thickness is highly susceptible to natural selection because thick enamel may prevent tooth failure. Consequently, it has been suggested that primates consuming stress-limited food on a regular basis would have thick-enameled molars in comparison to primates consuming soft food. Furthermore, the spatial distribution of enamel over a single tooth crown is not homogeneous, and thick enamel is expected to be more unevenly distributed in durophagous primates. Still, a proper methodology to quantitatively characterize enamel 3D distribution and test this hypothesis is yet to be developed. Unworn to slightly worn upper second molars belonging to 32 species of anthropoid primates and corresponding to a wide range of diets were digitized using high resolution microcomputed tomography. In addition, their durophagous ability was scored from existing literature. 3D average and relative enamel thickness were computed based on the volumetric reconstruction of the enamel cap. Geometric estimates of their average and relative enamel-dentine distance were also computed using 3D dental topography. Both methods gave different estimations of average and relative enamel thickness. This study also introduces pachymetric profiles, a method inspired from traditional topography to graphically characterize thick enamel distribution. Pachymetric profiles and topographic maps of enamel-dentine distance are combined to assess the evenness of thick enamel distribution. Both pachymetric profiles and topographic maps indicate that thick enamel is not significantly more unevenly distributed in durophagous species, except in Cercopithecidae. In this family, durophagous species such as mangabeys are characterized by an uneven thick enamel and high pachymetric profile slopes at the average enamel thickness, whereas non-durophagous species such as colobine monkeys are not. These results indicate that the distribution of thick enamel follows different patterns across anthropoids. Primates might have developed different durophagous strategies to answer the selective pressure exerted by stress-limited food.
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Affiliation(s)
- Ghislain Thiery
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
- School of Sociology and Anthropology, Sun Yat-Sen UniversityGuangzhou, China
| | - Vincent Lazzari
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
| | - Anusha Ramdarshan
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
| | - Franck Guy
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
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31
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Cohen JE. Earliest Divergence of Stagodontid (Mammalia: Marsupialiformes) Feeding Strategies from the Late Cretaceous (Turonian) of North America. J MAMM EVOL 2017. [DOI: 10.1007/s10914-017-9382-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Law CJ, Baliga VB, Tinker MT, Mehta RS. Asynchrony in craniomandibular development and growth in Enhydra lutris nereis (Carnivora: Mustelidae): are southern sea otters born to bite? Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blw050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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33
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Martínez LM, Estebaranz-Sánchez F, Galbany J, Pérez-Pérez A. Testing Dietary Hypotheses of East African Hominines Using Buccal Dental Microwear Data. PLoS One 2016; 11:e0165447. [PMID: 27851745 PMCID: PMC5112956 DOI: 10.1371/journal.pone.0165447] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/12/2016] [Indexed: 12/02/2022] Open
Abstract
There is much debate on the dietary adaptations of the robust hominin lineages during the Pliocene-Pleistocene transition. It has been argued that the shift from C3 to C4 ecosystems in Africa was the main factor responsible for the robust dental and facial anatomical adaptations of Paranthropus taxa, which might be indicative of the consumption of fibrous, abrasive plant foods in open environments. However, occlusal dental microwear data fail to provide evidence of such dietary adaptations and are not consistent with isotopic evidence that supports greater C4 food intake for the robust clades than for the gracile australopithecines. We provide evidence from buccal dental microwear data that supports softer dietary habits than expected for P. aethiopicus and P. boisei based both on masticatory apomorphies and isotopic analyses. On one hand, striation densities on the buccal enamel surfaces of paranthropines teeth are low, resembling those of H. habilis and clearly differing from those observed on H. ergaster, which display higher scratch densities indicative of the consumption of a wide assortment of highly abrasive foodstuffs. Buccal dental microwear patterns are consistent with those previously described for occlusal enamel surfaces, suggesting that Paranthropus consumed much softer diets than previously presumed and thus calling into question a strict interpretation of isotopic evidence. On the other hand, the significantly high buccal scratch densities observed in the H. ergaster specimens are not consistent with a highly specialized, mostly carnivorous diet; instead, they support the consumption of a wide range of highly abrasive food items.
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Affiliation(s)
- Laura Mónica Martínez
- Secció de Zoologia i Antropologia, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Ferran Estebaranz-Sánchez
- Secció de Zoologia i Antropologia, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Jordi Galbany
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington DC, United States of America
| | - Alejandro Pérez-Pérez
- Secció de Zoologia i Antropologia, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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Pampush JD, Spradley JP, Morse PE, Harrington AR, Allen KL, Boyer DM, Kay RF. Wear and its effects on dental topography measures in howling monkeys (Alouatta palliata). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 161:705-721. [PMID: 27634058 DOI: 10.1002/ajpa.23077] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/05/2016] [Accepted: 08/11/2016] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Three dental topography measurements: Dirichlet Normal Energy (DNE), Relief Index (RFI), and Orientation Patch Count Rotated (OPCR) are examined for their interaction with measures of wear, within and between upper and lower molars in Alouatta palliata. Potential inferences of the "dental sculpting" phenomenon are explored. MATERIALS AND METHODS Fifteen occluding pairs of howling monkey first molars (15 upper, 15 lower) opportunistically collected from La Pacifica, Costa Rica, were selected to sample wear stages ranging from unworn to heavily worn as measured by the Dentine Exposure Ratio (DER). DNE, RFI, and OPCR were measured from three-dimensional surface reconstructions (PLY files) derived from high-resolution CT scans. Relationships among the variables were tested with regression analyses. RESULTS Upper molars have more cutting edges, exhibiting significantly higher DNE, but have significantly lower RFI values. However, the relationships among the measures are concordant across both sets of molars. DER and EDJL are curvilinearly related. DER is positively correlated with DNE, negatively correlated with RFI, and uncorrelated with OPCR. EDJL is not correlated with DNE, or RFI, but is positively correlated with OPCR among lower molars only. DISCUSSION The relationships among these metrics suggest that howling monkey teeth adaptively engage macrowear. DNE increases with wear in this sample presumably improving food breakdown. RFI is initially high but declines with wear, suggesting that the initially high RFI safeguards against dental senescence. OPCR values in howling monkey teeth do not show a clear relationship with wear changes.
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Affiliation(s)
- James D Pampush
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Jackson P Spradley
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Paul E Morse
- Department of Anthropology, University of Florida, Gainesville, FL, USA.,Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | | | - Kari L Allen
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Doug M Boyer
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
| | - Richard F Kay
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA.,Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC, USA
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Law CJ, Young C, Mehta RS. Ontogenetic Scaling of Theoretical Bite Force in Southern Sea Otters (Enhydra lutris nereis). Physiol Biochem Zool 2016; 89:347-63. [DOI: 10.1086/688313] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Affiliation(s)
- Ivan Calandra
- GEGENAA - EA 3795; Université de Reims Champagne-Ardenne; CREA - 2 esplanade Roland Garros 51100 Reims France
| | - Gildas Merceron
- iPHEP UMR 7262; CNRS & Université de Poitiers; Bat. B35 - TSA-51106, 6 rue M. Brunet 86073 Poitiers France
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Lucas PW, Philip SM, Al-Qeoud D, Al-Draihim N, Saji S, van Casteren A. Structure and scale of the mechanics of mammalian dental enamel viewed from an evolutionary perspective. Evol Dev 2015; 18:54-61. [DOI: 10.1111/ede.12169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Peter W. Lucas
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Swapna M. Philip
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Dareen Al-Qeoud
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Nuha Al-Draihim
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Sreeja Saji
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Adam van Casteren
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology; Max Planck Institute for Evolutionary Anthropology; Deutscher Platz 6 D-04103 Leipzig Germany
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Berthaume MA, Dumont ER, Godfrey LR, Grosse IR. The effects of relative food item size on optimal tooth cusp sharpness during brittle food item processing. J R Soc Interface 2015; 11:20140965. [PMID: 25320068 DOI: 10.1098/rsif.2014.0965] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Teeth are often assumed to be optimal for their function, which allows researchers to derive dietary signatures from tooth shape. Most tooth shape analyses normalize for tooth size, potentially masking the relationship between relative food item size and tooth shape. Here, we model how relative food item size may affect optimal tooth cusp radius of curvature (RoC) during the fracture of brittle food items using a parametric finite-element (FE) model of a four-cusped molar. Morphospaces were created for four different food item sizes by altering cusp RoCs to determine whether optimal tooth shape changed as food item size changed. The morphospaces were also used to investigate whether variation in efficiency metrics (i.e. stresses, energy and optimality) changed as food item size changed. We found that optimal tooth shape changed as food item size changed, but that all optimal morphologies were similar, with one dull cusp that promoted high stresses in the food item and three cusps that acted to stabilize the food item. There were also positive relationships between food item size and the coefficients of variation for stresses in food item and optimality, and negative relationships between food item size and the coefficients of variation for stresses in the enamel and strain energy absorbed by the food item. These results suggest that relative food item size may play a role in selecting for optimal tooth shape, and the magnitude of these selective forces may change depending on food item size and which efficiency metric is being selected.
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Affiliation(s)
- Michael A Berthaume
- Medical and Biological Research Group, Department of Mechanical Engineering, University of Hull, Kingston upon Hull HU6 7RX, UK Department of Anthropology, University of Massachusetts, Amherst, MA 01003, USA
| | - Elizabeth R Dumont
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Laurie R Godfrey
- Department of Anthropology, University of Massachusetts, Amherst, MA 01003, USA
| | - Ian R Grosse
- Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01003, USA
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Enamel thickness trends in Plio-Pleistocene hominin mandibular molars. J Hum Evol 2015; 85:35-45. [DOI: 10.1016/j.jhevol.2015.03.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 11/14/2014] [Accepted: 03/25/2015] [Indexed: 11/21/2022]
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Ziscovici C, Lucas PW, Constantino PJ, Bromage TG, van Casteren A. Sea otter dental enamel is highly resistant to chipping due to its microstructure. Biol Lett 2015; 10:20140484. [PMID: 25319817 DOI: 10.1098/rsbl.2014.0484] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dental enamel is prone to damage by chipping with large hard objects at forces that depend on chip size and enamel toughness. Experiments on modern human teeth have suggested that some ante-mortem chips on fossil hominin enamel were produced by bite forces near physiological maxima. Here, we show that equivalent chips in sea otter enamel require even higher forces than human enamel. Increased fracture resistance correlates with more intense enamel prism decussation, often seen also in some fossil hominins. It is possible therefore that enamel chips in such hominins may have formed at even greater forces than currently envisaged.
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Affiliation(s)
- Charles Ziscovici
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, George Washington University, Washington, DC 20052, USA
| | - Peter W Lucas
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO BOX 24923, Safat 13110, Kuwait
| | - Paul J Constantino
- Department of Biology, Saint Michael's College, Colchester, VT 05439, USA
| | - Timothy G Bromage
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, 345 East 24th Street, New York, NY 10010, USA Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, 345 East 24th Street, New York, NY 10010, USA
| | - Adam van Casteren
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, PO BOX 24923, Safat 13110, Kuwait Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
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Abstract
A review is presented of the mechanical damage suffered by tooth crowns. This has been the subject of much recent research, resulting in a need to revise some of the thinking about the mechanisms involved. Damage is classified here by scale into macro-, meso- and microfracture. The focus is on the outer enamel coat because this is the contact tissue and where most fractures start. Enamel properties appear to be tailored to maximize hardness, but also to prevent fracture. The latter is achieved by the deployment of developmental flaws called enamel tufts. Macrofractures usually appear to initiate as extensions of tufts on the undersurface of the enamel adjacent to the enamel-dentine junction and extend from there into the enamel. Cracks that pass from the tooth surface tend to be deflected by an enamel region of high toughness; if they find the surface again, a chip (mesofracture) is produced. The real protection of the enamel-dentine junction here is the layer of decussating inner enamel. Finally, a novel analysis of mechanical wear (microfracture) suggests that the local toughness of the enamel is very important to its ability to resist tissue loss. Enamel and dentine have contrasting behaviours. Seen on a large scale, dentine is isotropic (behaving similarly in all directions) while enamel is anisotropic, but vice versa on a very small scale. These patterns have implications for anyone studying the fracture behaviour of teeth.
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Affiliation(s)
- Peter W. Lucas
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Jabriya, Kuwait
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Kato A, Tang N, Borries C, Papakyrikos AM, Hinde K, Miller E, Kunimatsu Y, Hirasaki E, Shimizu D, Smith TM. Intra- and interspecific variation in macaque molar enamel thickness. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2014; 155:447-59. [PMID: 25146639 DOI: 10.1002/ajpa.22593] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 08/04/2014] [Accepted: 08/05/2014] [Indexed: 11/06/2022]
Abstract
Enamel thickness has played an important role in studies of primate taxonomy, phylogeny, and functional morphology, although its variation among hominins is poorly understood. Macaques parallel hominins in their widespread geographic distribution, relative range of body sizes, and radiation during the last five million years. To explore enamel thickness variation, we quantified average and relative enamel thickness (AET and RET) in Macaca arctoides, Macaca fascicularis, Macaca fuscata, Macaca mulatta, Macaca nemestrina, and Macaca sylvanus. Enamel area, dentine area, and enamel-dentine junction length were measured from mesial sections of 386 molars scanned with micro-computed tomography, yielding AET and RET indices. Intraspecific sex differences were not found in AET or RET. Macaca fuscata had the highest AET and RET, M. fascicularis showed the lowest AET, and M. arctoides had the lowest RET. The latitudinal distribution of macaque species was associated with AET for these six species. Temperate macaques had thicker molar enamel than did tropical macaques, suggesting that thick enamel may be adaptive in seasonal environments. Additional research is needed to determine if thick enamel in temperate macaques is a response to intensified hard-object feeding, increased abrasion, and/or a broader diet with a greater range of food material properties. The extreme ecological flexibility of macaques may prohibit identification of consistent trends between specific diets and enamel thickness conditions. Such complications of interpretation of ecological variability, dietary diversity, and enamel thickness may similarly apply for fossil Homo species.
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Affiliation(s)
- Akiko Kato
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138; Department of Oral Anatomy, School of Dentistry, Aichi Gakuin University, Nagoya, 4648650, Japan
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Kupczik K, Lev-Tov Chattah N. The adaptive significance of enamel loss in the mandibular incisors of cercopithecine primates (Mammalia: Cercopithecidae): a finite element modelling study. PLoS One 2014; 9:e97677. [PMID: 24831704 PMCID: PMC4022739 DOI: 10.1371/journal.pone.0097677] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 04/23/2014] [Indexed: 11/19/2022] Open
Abstract
In several primate groups enamel is reduced or absent from the lingual (tongue) side of the mandibular incisor crowns akin to other placental and marsupial mammalian groups such as rodents, lagomorphs and wombats. Here we investigate the presumed adaptation of crowns with unilateral enamel to the incision of tough foods in cercopithecines, an Old World monkey subfamily, using a simulation approach. We developed and validated a finite element model of the lower central incisor of the rhesus macaque (Macaca mulatta) with labial enamel only to compute three-dimensional displacements and maximum principal stresses on the crown subjected to compressive loads varying in orientation. Moreover, we developed a model of a macaque incisor with enamel present on both labial and lingual aspects, thus resembling the ancestral condition found in the sister taxon, the leaf-eating colobines. The results showed that, concomitant with experimental results, the cercopithecine crown with unilateral enamel bends predominantly towards the inside of the mouth, while displacements decreased when both labial and lingual enamel are present. Importantly, the cercopithecine incisor crown experienced lower maximum principal stress on the lingual side compared to the incisor with enamel on the lingual and labial aspects under non-axial loads directed either towards the inside or outside of the mouth. These findings suggest that cercopithecine mandibular incisors are adapted to a wide range of ingestive behaviours compared to colobines. We conclude that the evolutionary loss of lingual enamel in cercopithecines has conferred a safeguard against crown failure under a loading regime assumed for the ingestion (peeling, scraping) of tough-skinned fruits.
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Affiliation(s)
- Kornelius Kupczik
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Institut für Spezielle Zoologie und Evolutionsbiologie, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Netta Lev-Tov Chattah
- The Department of Identification and Forensic Science, Israel National Police, Jerusalem, Israel
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McGraw WS, Vick AE, Daegling DJ. Dietary variation and food hardness in sooty mangabeys (Cercocebus atys): Implications for fallback foods and dental adaptation. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2014; 154:413-23. [DOI: 10.1002/ajpa.22525] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/21/2014] [Indexed: 11/11/2022]
Affiliation(s)
- W. Scott McGraw
- Department of Anthropology; The Ohio State University; Columbus OH 43210-1106
| | - Anna E. Vick
- Department of Social and Behavioral Sciences; Santa Fe College; Gainesville FL 32606
| | - David J. Daegling
- Department of Anthropology; University of Florida; Gainesville FL 32611-7305
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Lucas PW, Casteren AV, Al-Fadhalah K, Almusallam AS, Henry AG, Michael S, Watzke J, Reed DA, Diekwisch TGH, Strait DS, Atkins AG. The Role of Dust, Grit and Phytoliths in Tooth Wear. ANN ZOOL FENN 2014. [DOI: 10.5735/086.051.0215] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Dumont M, Tütken T, Kostka A, Duarte M, Borodin S. Structural and functional characterization of enamel pigmentation in shrews. J Struct Biol 2014; 186:38-48. [DOI: 10.1016/j.jsb.2014.02.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/06/2014] [Accepted: 02/11/2014] [Indexed: 10/25/2022]
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O'Brien S, Keown AJ, Constantino P, Xie Z, Bush MB. Revealing the structural and mechanical characteristics of ovine teeth. J Mech Behav Biomed Mater 2014; 30:176-85. [DOI: 10.1016/j.jmbbm.2013.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/10/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
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48
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Lawn BR, Bush MB, Barani A, Constantino PJ, Wroe S. Inferring biological evolution from fracture patterns in teeth. J Theor Biol 2013; 338:59-65. [DOI: 10.1016/j.jtbi.2013.08.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/21/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
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49
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Premolar microwear and tooth use in Australopithecus afarensis. J Hum Evol 2013; 65:282-93. [DOI: 10.1016/j.jhevol.2013.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 05/20/2013] [Accepted: 06/02/2013] [Indexed: 11/23/2022]
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Mahoney P. Testing functional and morphological interpretations of enamel thickness along the deciduous tooth row in human children. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 151:518-25. [DOI: 10.1002/ajpa.22289] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 04/08/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Patrick Mahoney
- School of Anthropology and Conservation, University of Kent; Canterbury; Kent CT2 7NR; UK
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