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Yi Z, Zanolli C, Liao W, Liang H, Yao Y, Tian C, Wang K, Xu G, Wang W. Enamel thickness in the deciduous postcanine dentition of fossil and extant Pongo. J Hum Evol 2024; 191:103493. [PMID: 38714076 DOI: 10.1016/j.jhevol.2024.103493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/01/2024] [Accepted: 01/02/2024] [Indexed: 05/09/2024]
Affiliation(s)
- Zhixing Yi
- Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China; Guangxi Academy of Sciences, Nanning, 530007, China
| | - Clément Zanolli
- Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, F-33600, Pessac, France
| | - Wei Liao
- Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China
| | - Hua Liang
- Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China
| | - Yanyan Yao
- Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China; Anthropology Museum of Guangxi, Nanning, 530012, China
| | - Chun Tian
- Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China
| | - Kun Wang
- School of Resources and Geosciences, China University of Mining and Technology, Xuzhou, 221116, China
| | - Guilin Xu
- Guangxi Academy of Sciences, Nanning, 530007, China; Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education, Nanning Normal University, Nanning, 530001, China.
| | - Wei Wang
- Institute of Cultural Heritage, Shandong University, Qingdao, 266237, China.
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Mahoney P, McFarlane G, Taurozzi AJ, Madupe PP, O'Hara MC, Molopyane K, Cappellini E, Hawks J, Skinner MM, Berger L. Human-like enamel growth in Homo naledi. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24893. [PMID: 38180115 DOI: 10.1002/ajpa.24893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/12/2023] [Accepted: 12/14/2023] [Indexed: 01/06/2024]
Abstract
OBJECTIVES A modern pattern (rate and duration) of dental development occurs relatively recently during human evolution. Given the temporal overlap of Homo naledi with the first appearance of fossil Homo sapiens in Africa, this small-bodied and small-brained hominin presents an opportunity to elucidate the evolution of enamel growth in the hominin clade. Here we conduct the first histological study of two permanent mandibular canines and one permanent maxillary first molar, representing three individuals attributed to H. naledi. We reconstruct the rate and duration of enamel growth and compare these findings to those reported for other fossil hominins and recent humans. MATERIALS AND METHODS Thin sections of each tooth were produced using standard histological methods. Daily and longer period incremental markings were measured to reconstruct enamel secretion and extension rates, Retzius periodicity, canine crown and molar cusp formation time. RESULTS Daily enamel secretion rates overlapped with those from recent hominins. Canine crown formation time is similar to that observed in recent Europeans but is longer than canine formation times reported for most other hominins including Australopithecus and H. neanderthalensis. The extended period of canine formation appears to be due to a relatively tall enamel crown and a sustained slow rate of enamel extension in the cervical portion of the crown. A Retzius periodicity of 11 days for the canines, and nine days for the molar, in H. naledi parallel results found in recent humans. An 11-day periodicity has not been reported for Late Pleistocene Homo (H. erectus, H. neanderthalensis) and is rarely found in Australopithecus and Paranthropus species. DISCUSSION Enamel growth of H. naledi is most similar to recent humans though comparative data are limited for most fossil hominin species. The high Retzius periodicity values do not follow expectations for a small-brained hominin.
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Affiliation(s)
- Patrick Mahoney
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Gina McFarlane
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Alberto J Taurozzi
- Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Palesa P Madupe
- Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
| | - Mackie C O'Hara
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Keneiloe Molopyane
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- The National Geographic Society, Washington, District of Columbia, USA
| | - Enrico Cappellini
- Section for GeoGenetics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - John Hawks
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, USA
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Lee Berger
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
- The National Geographic Society, Washington, District of Columbia, USA
- The Carnegie Institution for Science, Washington, District of Columbia, USA
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Najafzadeh A, Hernaiz-García M, Benazzi S, Chen B, Hublin JJ, Kullmer O, Pokhojaev A, Sarig R, Sorrentino R, Vazzana A, Fiorenza L. Finite element analysis of Neanderthal and early Homo sapiens maxillary central incisor. J Hum Evol 2024; 189:103512. [PMID: 38461589 DOI: 10.1016/j.jhevol.2024.103512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 03/12/2024]
Abstract
Neanderthal anterior teeth are very large and have a distinctive morphology characterized by robust 'shovel-shaped' crowns. These features are frequently seen as adaptive responses in dissipating heavy mechanical loads resulting from masticatory and non-masticatory activities. Although the long-standing debate surrounding this hypothesis has played a central role in paleoanthropology, is still unclear if Neanderthal anterior teeth can resist high mechanical loads or not. A novel way to answer this question is to use a multidisciplinary approach that considers together tooth architecture, dental wear and jaw movements. The aim of this study is to functionally reposition the teeth of Le Moustier 1 (a Neanderthal adolescent) and Qafzeh 9 (an early Homo sapiens adolescent) derived from wear facet mapping, occlusal fingerprint analysis and physical dental restoration methods. The restored dental arches are then used to perform finite element analysis on the left central maxillary incisor during edge-to-edge occlusion. The results show stress distribution differences between Le Moustier 1 and Qafzeh 9, with the former displaying higher tensile stress in enamel around the lingual fossa but lower concentration of stress in the lingual aspect of the root surface. These results seem to suggest that the presence of labial convexity, lingual tubercle and of a large root surface in Le Moustier 1 incisor helps in dissipating mechanical stress. The absence of these dental features in Qafzeh 9 is compensated by the presence of a thicker enamel, which helps in reducing the stress in the tooth crown.
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Affiliation(s)
- Ali Najafzadeh
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia; Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, 3800, Australia
| | - María Hernaiz-García
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Stefano Benazzi
- Department of Cultural Heritage, University of Bologna, Ravenna, 48121, Italy
| | - Bernard Chen
- Department of Surgery, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Jean-Jacques Hublin
- Chaire de Paléoanthropologie, CIRB (UMR 7241-U1050), Collège de France, 11, Place Marcelin-Berthelot, 75231, Paris, Cedex 05, France; Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany
| | - Ottmar Kullmer
- Division of Palaeoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt a. M, 60325, Germany; Department of Palaeobiology and Environment, Institute of Ecology, Evolution, and Diversity, Goethe University, Frankfurt a. M, 60438, Germany
| | - Ariel Pokhojaev
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Rachel Sarig
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel; Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Rita Sorrentino
- Department of Cultural Heritage, University of Bologna, Ravenna, 48121, Italy; Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, 40126, Italy
| | - Antonino Vazzana
- Department of Cultural Heritage, University of Bologna, Ravenna, 48121, Italy
| | - Luca Fiorenza
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia.
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Modesto-Mata M, de la Fuente Valentín L, Hlusko LJ, Martínez de Pinillos M, Towle I, García-Campos C, Martinón-Torres M, Bermúdez de Castro JM. Artificial neural networks reconstruct missing perikymata in worn teeth. Anat Rec (Hoboken) 2024. [PMID: 38468123 DOI: 10.1002/ar.25416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 02/08/2024] [Accepted: 02/11/2024] [Indexed: 03/13/2024]
Abstract
Dental evolutionary studies in hominins are key to understanding how our ancestors and close fossil relatives grew from the early stages of embryogenesis into adults. In a sense, teeth are like an airplane's 'black box' as they record important variables for assessing developmental timing, enabling comparisons within and between populations, species, and genera. The ability to discern this type of nuanced information is embedded in the nature of how tooth enamel and dentin form: incrementally and over years. This incremental growth leaves chronological indicators in the histological structure of enamel, visible on the crown surface as perikymata. These structures are used in the process of reconstructing the rate and timing of tooth formation. Unfortunately, the developmentally earliest growth lines in lateral enamel are quickly lost to wear once the tooth crown erupts. We developed a method to reconstruct these earliest, missing perilymata from worn teeth through knowledge of the later-developed, visible perikymata for all tooth types (incisors, canines, premolars, and molars) using a modern human dataset. Building on our previous research using polynomial regressions, here we describe an artificial neural networks (ANN) method. This new ANN method mostly predicts within 2 counts the number of perikymata present in each of the first three deciles of the crown height for all tooth types. Our ANN method for estimating perikymata lost through wear has two immediate benefits: more accurate values can be produced and worn teeth can be included in dental research. This tool is available on the open-source platform R within the package teethR released under GPL v3.0 license, enabling other researchers the opportunity to expand their datasets for studies of periodicity in histological growth, dental development, and evolution.
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Affiliation(s)
- Mario Modesto-Mata
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
- Universidad Internacional de La Rioja (UNIR), Logroño (La Rioja), Spain
| | | | - Leslea J Hlusko
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
| | - Marina Martínez de Pinillos
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
- Laboratorio de Evolución Humana (LEH), Universidad de Burgos, Burgos, Spain
| | - Ian Towle
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
| | - Cecilia García-Campos
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
- Facultad de Ciencias, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid, Spain
| | - María Martinón-Torres
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
- Department of Anthropology, University College London, London, UK
| | - José María Bermúdez de Castro
- Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain
- Department of Anthropology, University College London, London, UK
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Guatelli-Steinberg D, Gurian K, McGraw WS. Differences in maxillary premolar form between Cercocebus and Lophocebus. J Hum Evol 2024; 186:103467. [PMID: 37992631 DOI: 10.1016/j.jhevol.2023.103467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/24/2023]
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.
| | - Kaita Gurian
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA
| | - W Scott McGraw
- Department of Anthropology, The Ohio State University, 174 West 18th Ave, Columbus, OH, 43210, USA
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Guatelli-Steinberg D, Renteria C, Grimm JR, Maeret Carpenter I, Arola DD, McGraw WS. How mangabey molar form differs under routine vs. fallback hard-object feeding regimes. PeerJ 2023; 11:e16534. [PMID: 38099313 PMCID: PMC10720418 DOI: 10.7717/peerj.16534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/07/2023] [Indexed: 12/17/2023] Open
Abstract
Background Components of diet known as fallback foods are argued to be critical in shaping primate dental anatomy. Such foods of low(er) nutritional quality are often non-preferred, mechanically challenging resources that species resort to during ecological crunch periods. An oft-cited example of the importance of dietary fallbacks in shaping primate anatomy is the grey-cheeked mangabey Lophocebus albigena. This species relies upon hard seeds only when softer, preferred resources are not available, a fact which has been linked to its thick dental enamel. Another mangabey species with thick enamel, the sooty mangabey Cercocebus atys, processes a mechanically challenging food year-round. That the two mangabey species are both thickly-enameled suggests that both fallback and routine consumption of hard foods are associated with the same anatomical feature, complicating interpretations of thick enamel in the fossil record. We anticipated that aspects of enamel other than its thickness might differ between Cercocebus atys and Lophocebus albigena. We hypothesized that to function adequately under a dietary regime of routine hard-object feeding, the molars of Cercocebus atys would be more fracture and wear resistant than those of Lophocebus albigena. Methods Here we investigated critical fracture loads, nanomechanical properties of enamel, and enamel decussation in Cercocebus atys and Lophocebus albigena. Molars of Cercopithecus, a genus not associated with hard-object feeding, were included for comparison. Critical loads were estimated using measurements from 2D µCT slices of upper and lower molars. Nanomechanical properties (by nanoindentation) and decussation of enamel prisms (by SEM-imaging) in trigon basins of one upper second molar per taxon were compared. Results Protocone and protoconid critical fracture loads were significantly greater in Cercocebus atys than Lophocebus albigena and greater in both than in Cercopithecus. Elastic modulus, hardness, and elasticity index in most regions of the crown were greater in Cercocebus atys than in the other two taxa, with the greatest difference in the outer enamel. All taxa had decussated enamel, but that of Cercocebus atys uniquely exhibited a bundle of transversely oriented prisms cervical to the radial enamel. Quantitative comparison of in-plane and out-of-plane prism angles suggests that decussation in trigon basin enamel is more complex in Cercocebus atys than it is in either Lophocebus albigena or Cercopithecus cephus. These findings suggest that Cercocebus atys molars are more fracture and wear resistant than those of Lophocebus albigena and Cercopithecus. Recognition of these differences between Cercocebus atys and Lophocebus albigena molars sharpens our understanding of associations between hard-object feeding and dental anatomy under conditions of routine vs. fallback hard-object feeding and provides a basis for dietary inference in fossil primates, including hominins.
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Affiliation(s)
- Debbie Guatelli-Steinberg
- Department of Anthropology, The Ohio State University, Columbus, OH, United States of America
- School of Anthropology and Conservation, University of Kent, Canterbury, Kent, United Kingdom
| | - Cameron Renteria
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, United States of America
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, United States of America
| | - Jack R. Grimm
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, United States of America
| | - Izabela Maeret Carpenter
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, United States of America
| | - Dwayne D. Arola
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, United States of America
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, United States of America
- Department of Mechanical Engineering, University of Washington, Seattle, WA, United States of America
- Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, United States of America
| | - W. Scott McGraw
- Department of Anthropology, The Ohio State University, Columbus, OH, United States of America
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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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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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