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Holmes MA, Terhune CE, Chalk-Wilayto J, Yoakum CB, Taylor P, Ramirez R, Solís MP, Polvadore TA, Ross CF, Taylor AB, Fogaca MD, Laird MF. Ontogenetic changes in jaw leverage and skull shape in tufted and untufted capuchins. J Morphol 2024; 285:e21705. [PMID: 38704727 DOI: 10.1002/jmor.21705] [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] [Revised: 04/19/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024]
Abstract
The ontogeny of feeding is characterized by shifting functional demands concurrent with changes in craniofacial anatomy; relationships between these factors will look different in primates with disparate feeding behaviors during development. This study examines the ontogeny of skull morphology and jaw leverage in tufted (Sapajus) and untufted (Cebus) capuchin monkeys. Unlike Cebus, Sapajus have a mechanically challenging diet and behavioral observations of juvenile Sapajus suggest these foods are exploited early in development. Landmarks were placed on three-dimensional surface models of an ontogenetic series of Sapajus and Cebus skulls (n = 53) and used to generate shape data and jaw-leverage estimates across the tooth row for three jaw-closing muscles (temporalis, masseter, medial pterygoid) as well as a weighted combined estimate. Using geometric morphometric methods, we found that skull shape diverges early and shape is significantly different between Sapajus and Cebus throughout ontogeny. Additionally, jaw leverage varies with age and position on the tooth row and is greater in Sapajus compared to Cebus when calculated at the permanent dentition. We used two-block partial least squares analyses to identify covariance between skull shape and each of our jaw muscle leverage estimates. Sapajus, but not Cebus, has significant covariance between all leverage estimates at the anterior dentition. Our findings show that Sapajus and Cebus exhibit distinct craniofacial morphologies early in ontogeny and strong covariance between leverage estimates and craniofacial shape in Sapajus. These results are consistent with prior behavioral and comparative work suggesting these differences are a function of selection for exploiting mechanically challenging foods in Sapajus, and further emphasize that these differences appear quite early in ontogeny. This research builds on prior work that has highlighted the importance of understanding ontogeny for interpreting adult morphology.
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Affiliation(s)
- Megan A Holmes
- Department of Family Medicine and Community Health, Duke University School of Medicine, Durham, North Carolina, USA
| | - Claire E Terhune
- Department of Anthropology, University of Arkansas, Fayetteville, North Carolina, USA
| | - Janine Chalk-Wilayto
- Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA
| | - Caitlin B Yoakum
- Department of Anatomy, Arkansas College of Health Education, Fort Smith, Arkansas, USA
| | - Parker Taylor
- Department of Anthropology, University of Arkansas, Fayetteville, North Carolina, USA
| | - Rocio Ramirez
- Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, California, USA
| | - Megan P Solís
- Department of Anthropology, Stony Brook University, Stony Brook, New York, USA
| | - Taylor A Polvadore
- Department of Anthropology, University of Arkansas, Fayetteville, North Carolina, USA
| | - Callum F Ross
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, USA
| | - Andrea B Taylor
- Department of Foundational Biomedical Sciences, Touro University California, Vallejo, California, USA
| | | | - Myra F Laird
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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2
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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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Wang JL, Wang J, Chen KN, Guo JQ, Xu XL, Guo CB. Designing customized temporomandibular fossa prosthesis based on envelope surface of condyle movement: validation via in silico musculoskeletal simulation. Front Bioeng Biotechnol 2023; 11:1273263. [PMID: 38026896 PMCID: PMC10644477 DOI: 10.3389/fbioe.2023.1273263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Objective: This study presents an innovative articular fossa prosthesis generated by the envelope surface of condyle movement, and compares its mandible movements, muscle activities, and joint reaction forces with two temporomandibular joint (TMJ) prostheses using multibody musculoskeletal simulation. Methods: A healthy 23-year-old female was recruited for this study. Cone-beam computed tomographic (CBCT) was performed to reconstruct the mandibular bone geometry. A customized TMJ fossa prosthesis was designed based on the subject-specific envelope surface of condyle movement (ESCM). Mandibular kinematics and jaw-closing muscle electromyography (EMG) were simultaneously recorded during maximum jaw opening-closing movements. To validate our prosthesis design, a mandibular musculoskeletal model was established using flexible multibody dynamics and the obtained kinematics and EMG data. The Biomet fossa prosthesis and the ellipsoidal fossa prosthesis designed by imitating the lower limb prostheses were used for comparison. Simulations were performed to analyze the effects of different fossa prostheses on jaw opening-closing motions, mandibular muscle activation, and contact forces. Results: The maximum opening displacement for the envelope-based fossa prosthesis was greater than those for Biomet and ellipsoidal prostheses (36 mm, 35 mm, and 33 mm, respectively). The mandibular musculoskeletal model with ellipsoidal prosthesis led to dislocation near maximal jaw opening. Compared to Biomet, the envelope-based fossa reduced the digastric and lateral pterygoid activation at maximal jaw opening. It also reduced the maximal resistance to condylar sliding on the intact side by 63.2 N. Conclusion: A customized TMJ fossa prosthesis was successfully developed using the ESCM concept. Our study of musculoskeletal multibody modeling has highlighted its advantages and potential. The artificial fossa design successfully achieved a wider condylar range of motion. It also reduced the activation of jaw opening muscles on the affected side and resistance on the intact side. This study showed that an ESCM-based approach may be useful for optimizing TMJ fossa prostheses design.
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Affiliation(s)
- Jun-Lin Wang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Jing Wang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Ke-Nan Chen
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Jian-Qiao Guo
- MOE Key Laboratory of Dynamics and Control of Flight Vehicle, School of Aerospace Engineering, Beijing Institute of Technology, Beijing, China
| | - Xiang-Liang Xu
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
| | - Chuan-Bin Guo
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, National Center of Stomatology, National Clinical Research Center for Oral Diseases, National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing Key Laboratory of Digital Stomatology, Research Center of Engineering and Technology for Computerized Dentistry, Ministry of Health, NMPA Key Laboratory for Dental Materials, Beijing, China
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Morse PE, Pampush JD, Kay RF. Dental topography of the Oligocene anthropoids Aegyptopithecus zeuxis and Apidium phiomense: Paleodietary insights from analysis of wear series. J Hum Evol 2023; 180:103387. [PMID: 37245335 DOI: 10.1016/j.jhevol.2023.103387] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/30/2023]
Abstract
Fossil primate dietary inference is enhanced when ascertained through multiple, distinct proxies. Dental topography can be used to assess changes in occlusal morphology with macrowear, providing insight on tooth use and function across the lifespans of individuals. We measured convex Dirichlet normal energy-a dental topography metric reflecting occlusal sharpness of features such as cusps and crests-in macrowear series of the second mandibular molars of two African anthropoid taxa from ∼30 Ma (Aegyptopithecus zeuxis and Apidium phiomense). Wear was quantified via three proxies: occlusal dentine exposure, inverse relief index, and inverse occlusal relief. The same measurements were calculated on macrowear series of four extant platyrrhine taxa (Alouatta, Ateles, Plecturocebus, and Sapajus apella) to provide an analogical framework for dietary inference in the fossil taxa. We predicted that Ae. zeuxis and Ap. phiomense would show similar patterns in topographic change with wear to one another and to extant platyrrhine frugivores like Ateles and Plecturocebus. The fossil taxa have similar distributions of convex Dirichlet normal energy to one another, and high amounts of concave Dirichlet normal energy 'noise' in unworn molars-a pattern shared with extant hominids that may distort dietary interpretations. Inverse relief index was the most useful wear proxy for comparison among the taxa in this study which possess disparate enamel thicknesses. Contrary to expectations, Ae. zeuxis and Ap. phiomense both resemble S. apella in exhibiting an initial decline in convex Dirichlet normal energy followed by an increase at the latest stages of wear as measured by inverse relief index, lending support to previous suggestions that hard-object feeding played a role in their dietary ecology. Based on these results and previous analyses of molar shearing quotients, microwear, and enamel microstructure, we suggest that Ae. zeuxis had a pitheciine-like strategy of seed predation, whereas Ap. phiomense potentially consumed berry-like compound fruits with hard seeds.
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Affiliation(s)
- Paul E Morse
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA; Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA.
| | - James D Pampush
- Department of Exercise Science, High Point University, High Point, NC 27260, USA; Department of Physician Assistant Studies, High Point University, High Point, NC 27260, USA
| | - Richard F Kay
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA; Division of Earth and Climate Sciences, Nicholas School, Duke University, Durham, NC 27708, USA
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Tanoue K, Shimada K. Jaw mechanics in macrophagous lamniform sharks and their evolutionary and functional implications. Anat Rec (Hoboken) 2023; 306:311-325. [PMID: 36059141 DOI: 10.1002/ar.25071] [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: 05/18/2022] [Revised: 07/03/2022] [Accepted: 08/29/2022] [Indexed: 01/25/2023]
Abstract
Jaw mechanics of lamniform sharks were examined three-dimensionally to analyze the variability in jaw shape and the evolution of the jaw system based on the extant macrophagous species. Three-dimensional lever analysis was applied to lamniform jaws to calculate bite force at each tooth relative to maximum input force from jaw adductor muscles for interspecific comparison of efficiency in lamniform jaws. When total input force from the jaw adductor muscles on both working and balancing sides of the skull is considered, input force varies along the jaw because the contribution by balancing side muscles is not constant. The phylogenetically basal-most species, Mitsukurina owstoni, has the least efficient jaws due to posteriorly positioned jaw adductor muscles. Our study shows that the higher efficiency of jaws is regarded as apomorphic in lamniform phylogeny owing to the anterior extension of jaw adductor muscles relative to M. owstoni and a relative decrease in jaw length in relation to width seen in some species, both of which increase leverage. Differences in the efficiency of jaws among derived genera or species are due to the morphology of their jaws. The relationship between calculated bite force relative to maximum input force and tooth morphology indicates low relative bite forces being exerted at anteriorly located, narrow, piercing teeth, whereas high relative bite forces at posteriorly located, broad, cutting, or crushing-type teeth. As a result, the biting pressure during feeding is maintained throughout the tooth series.
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Affiliation(s)
- Kyo Tanoue
- Department of Earth System Science, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Kenshu Shimada
- Department of Environmental Science and Studies and Department of Biological Sciences, DePaul University, Chicago, Illinois, USA.,Sternberg Museum of Natural History, Fort Hays State University, Hays, Kansas, USA
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6
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Kulkarni V, Gupta H, Gupta S, Ghosh S. Evaluation of occlusal forces using T scan analysis following mandibular fracture fixation. Natl J Maxillofac Surg 2023; 14:35-40. [PMID: 37273425 PMCID: PMC10235733 DOI: 10.4103/njms.njms_143_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 06/06/2023] Open
Abstract
Introduction Mandible receives maximum impact following maxillofacial trauma. The dentate segment in particular is of importance as it has a direct bearing on the occlusive forces. The studies that have been carried out are either based on crude clinical evaluations or make use of elaborate and labor-intensive techniques. This study made use of T-scan analysis for objective identification of occlusive forces following mandibular fracture fixation. Materials and Methods Eighty clinic-radiologically diagnosed cases of dentate segments of the mandible were considered, after random sampling method. The occlusion analysis was done by use of a T scan to obtain Relatively Occlusal Force. The procedure was repeated at 04-, 24-, 36-, and 48-weeks intervals. The data was recorded on Excel Spreadsheet (Microsoft Inc) and analysis was done using SPSS software. Results The cases were predominantly males with a homogenous distribution of cases of age. The age versus gender distribution was more skewed in the female subgroup with a higher kurtosis value. Both evaluative (Pearson's) and inferential (paired t) tests were applied to reason the study. It was observed that the ROF values decreased in values as compared to pre-operative/post-treatment (Difference of Mean = 2.19, SE = 2.13) compared to 4 (Difference of Mean = -0.40 SE = 0.188),24 (Difference of Mean = -1.22, SE = 0.24) and 36 (Difference of Mean = -3.24, SE = 0.30) weeks, which however surpassed the pre-operative levels at 48 weeks post-operative period. This is suggestive of impending muscular imbalance in the initial periods. The surpass of 48 weeks may be due to optimal forces that were their pre-trauma. Conclusion Mandibular fracture fixation is the most widely used and also a time-tested modality in the management of mandibular trauma. The evaluation of occlusive forces needs an understanding of their behavior following such fixation. The present study used T-scan analysis to objectify such forces and added extra insight apart from clinical evaluations of tooth contact and parafunctional movements.
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Affiliation(s)
- Vishal Kulkarni
- Department of Oral and Maxillofacial Surgery, Command Military Dental Centre, Lucknow, Uttar Pradesh, India
| | - Hemant Gupta
- Department of Oral and Maxillofacial Surgery, Babu Banarasi Das College of Dental Sciences, Lucknow, Uttar Pradesh, India
| | - Swati Gupta
- Department of Prosthodontics, Babu Banarasi Das College of Dental Sciences, Lucknow, Uttar Pradesh, India
| | - Sirsendu Ghosh
- Department of Biostatistics, Command Military Dental Centre, Lucknow, Uttar Pradesh, India
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7
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Salunkhe SM, Kadam H, Nakhate M, Edsor E, Kamble R, Vadane AK. Evaluation of Masticatory Forces in Patients Treated for Mandibular Fractures: A Case-Control Study. Cureus 2022; 14:e29295. [PMID: 36277531 PMCID: PMC9578546 DOI: 10.7759/cureus.29295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/09/2022] [Indexed: 11/15/2022] Open
Abstract
Purpose: This study aimed to evaluate the masticatory forces in patients treated for mandibular fractures. To assess the magnitude of damage to the masticatory system caused by the various mandibular fractures and the period required for their normalization. Materials and Methods: Data were recorded from the authentic and original bite force measurement device from 2015 to 2017. The sample was composed of 30 isolated mandible fractures patients, Group 1 consisting 15 patients with unilateral mandible fractures, Group 2 consisting 15 patients with bilateral mandible fractures, treated with ORIF (open reduction immobilization fixation) under general anesthesia, and Group 3 was a control group. Predictor variables were drawn from predefined intervals for three months (ninth POW) postoperative week. The condition of wound healing was checked, and masticatory forces are measured at the first, fourth, sixth, and ninth postoperative weeks and compared with a control group of the same age and gender. The outcome variables were the success rate and associated complications. Results: For the study, a total of 30 patients with 15 bilateral and 15 unilateral isolated mandibular fractures were included. The study result suggests that the patient had lower bite forces relative to the control group at all intervals. All patients showed a significant increase in the bite force values from the first to the fourth postoperative weeks (p = ‹0.001), which also increased significantly from the fourth to sixth postoperative weeks (p = ‹0.001), and from the sixth to the ninth week. Conclusion: Based on the results obtained from our study, we conclude that there is a temporary adverse effect on masticatory forces. Fracture of the bilateral mandible has a stronger influence on bite force than unilateral mandible fracture. These fractures also take a longer time to normalize.
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8
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Santana SE, Grossnickle DM, Sadier A, Patterson E, Sears KE. Bat Dentitions: A Model System for Studies at The Interface of Development, Biomechanics, and Evolution. Integr Comp Biol 2022; 62:icac042. [PMID: 35575617 DOI: 10.1093/icb/icac042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The evolution of complex dentitions was a major innovation in mammals that facilitated the expansion into new dietary niches that imposed selection for tight form-function relationships. Teeth allow mammals to ingest and process food items by applying forces produced by a third-class lever system composed by the jaw adductors, the cranium, and the mandible. Physical laws determine changes in jaw adductor (biting) forces at different bite point locations along the mandible (outlever), thus individual teeth are expected to experience different mechanical regimes during feeding. If the mammal dentition exhibits functional adaptations to mandible feeding biomechanics, then teeth are expected to have evolved to develop mechanically-advantageous sizes, shapes, and positions. Here, we present bats as a model system to test this hypothesis and, more generally, for integrative studies of mammal dental diversity. We combine a field-collected dataset of bite forces along the tooth row with data on dental and mandible morphology across 30 bat species. We (1) describe, for the first time, bite force trends along the tooth row of bats, (2) use phylogenetic comparative methods to investigate relationships among bite force patterns, tooth and mandible morphology, and (3) hypothesize how these biting mechanics patterns may relate to the developmental processes controlling tooth formation. We find that bite force variation along the tooth row is consistent with predictions from lever mechanics models, with most species having the greatest bite force at the first lower molar. The cross-sectional shape of the mandible body is strongly associated with the position of maximum bite force along the tooth row, likely reflecting mandibular adaptations to varying stress patterns among species. Further, dental dietary adaptations seem to be related to bite force variation along molariform teeth, with insectivorous species exhibiting greater bite force more anteriorly, narrower teeth and mandibles, and frugivores/omnivores showing greater bite force more posteriorly, wider teeth and mandibles. As these craniodental traits are linked through development, dietary specialization appears to have shaped intrinsic mechanisms controlling traits relevant to feeding performance.
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Affiliation(s)
- Sharlene E Santana
- Department of Biology, University of Washington, Seattle, WA
- Burke Museum of Natural History and Culture, University of Washington, Seattle, WA
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Laird MF, Punjani Z, Oshay RR, Wright BW, Fogaça MD, Casteren A, Izar P, Visalberghi E, Fragazy D, Strait DS, Ross CF, Wright KA. Feeding postural behaviors and food geometric and material properties in bearded capuchin monkeys (
Sapajus libidinosus
). AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022. [PMCID: PMC9305483 DOI: 10.1002/ajpa.24501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Objectives Foods that are geometrically and mechanically challenging to eat have been associated with specializations in feeding behavior and craniodental morphology across primates, and many of these foods are embedded, requiring a variety of positional behaviors during feeding. However, variation in positional behaviors in response to food properties is not well understood. Here, we examine differences in feeding postural behaviors across feeding events in relation to substrate and food geometric and material properties in a species of extractive foragers, bearded capuchins (Sapajus libidinosus). Methods and materials We coded over 1400 co‐occurring postural and feeding behaviors, their durations, and relative sizes of substrate and food from videos recorded at Fazenda Boa Vista in Gilbués, Piauí, Brazil. Food material properties were measured from foods collected at the time of the video recordings. Results Our results suggest that bearded capuchin feeding postures significantly differ across the feeding sequence, with substrate size, and between foods of high and low toughness and elastic modulus. Feeding postures were less variable for highly mechanically challenging foods. Food size also had a significant effect on postural behaviors. Large foods were more likely to be associated with suspended postures and small foods with sitting and squatting. Feeding postural behaviors were best explained by a combination of substrate and food variables. Conclusions Our results indicate that food geometric and mechanical properties have a significant influence on feeding postural behaviors in bearded capuchins. We posit that feeding postural behaviors reflect a combination of substrate variables and food properties, and large, mechanically challenging foods have a limiting effect on postural variation.
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Affiliation(s)
- Myra F. Laird
- Department of Integrative Anatomical Sciences University of Southern California Los Angeles California USA
| | - Zeenia Punjani
- Department of Integrative Anatomical Sciences University of Southern California Los Angeles California USA
| | - Rachel R. Oshay
- Department of Integrative Anatomical Sciences University of Southern California Los Angeles California USA
| | - Barth W. Wright
- Department of Surgery University of Kansas Medical Center Kansas City Kansas USA
| | - Mariana Dutra Fogaça
- Department of Biomedical Sciences Institute of Population Genetics, University of Veterinary Medicine Vienna Austria
- Neotropical Primates Research Group – NeoPReGo São Paulo Brazil
| | - Adam Casteren
- Department of Human Evolution Max Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Patrícia Izar
- Department of Experimental Psychology University of São Paulo São Paulo Brazil
| | - Elisabetta Visalberghi
- Institute of Cognitive Sciences and Technologies, National Research Council (CNR) Rome Italy
| | - Dorothy Fragazy
- Department of Psychology University of Georgia Athens Georgia USA
| | - David S. Strait
- Department of Anthropology Washington University in St. Louis St. Louis Missouri USA
- Palaeo‐Research Institute, University of Johannesburg, Cnr Kingsway and University Road Auckland Park Auckland Park South Africa
| | - Callum F. Ross
- Department of Organismal Biology and Anatomy University of Chicago Chicago Illinois USA
| | - Kristin A. Wright
- Department of Biomedical Sciences University of Missouri Kansas City School of Medicine Kansas City Missouri USA
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10
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Deutsch AR, Dickinson E, Whichard VA, Lagomarsino GR, Perry JMG, Kupczik K, Hartstone-Rose A. Primate body mass and dietary correlates of tooth root surface area. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:4-26. [PMID: 36787710 DOI: 10.1002/ajpa.24430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/26/2021] [Accepted: 09/22/2021] [Indexed: 11/10/2022]
Abstract
OBJECTIVES This study aims to examine primate postcanine tooth root surface area (TRSA) in the context of two ecological variables (diet and bite force). We also assess scaling relationships within distinct taxonomic groups and across the order as a whole. MATERIALS AND METHODS Mandibular postcanine TRSA was measured using a three-dimensional computed tomography (CT) method for catarrhine (N = 27), platyrrhine (N = 21), and strepsirrhine (N = 24) taxa; this represents the first sample of strepsirrhines. Two different body size proxies were used: cranial geometric mean (GM) using nine linear measurements, and literature-derived body mass (BM). RESULTS TRSA correlated strongly with body size, scaling with positive allometry or isometry across the order as a whole; however, scaling differed significantly between taxa for some teeth. Among Strepsirrhini, molar TRSA relative to GM differed significantly between folivores and pliant-object feeders. Additionally, P4 TRSA relative to BM differentiated folivores from both hard- and pliant-object feeders. Among Cercopithecoidea, P4 TRSA adjusted by GM differed between hard- and pliant-object feeders. DISCUSSION Dietary signals in TRSA appear primarily driven by high frequency loading experienced by folivores. Stronger and more frequent dietary signals were observed within Strepsirrhini relative to Haplorhini. This may reflect the constraints of orthognathism within the latter, constraining the adaptability of their postcanine teeth. Finally, because of the strong correlation between TRSA and BM for each tooth locus (mean r2 = 0.82), TRSA can be used to predict BM in fossil primates using provided equations.
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Affiliation(s)
- Ashley R Deutsch
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Edwin Dickinson
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Victoria A Whichard
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Giulia R Lagomarsino
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Jonathan M G Perry
- Department of Physical Therapy Education, Western University of Health Sciences, Lebanon, Oregon, USA
| | - Kornelius Kupczik
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Anthropology, University of Chile, Santiago, Chile
| | - Adam Hartstone-Rose
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
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11
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Glowacka H, Schwartz GT. A biomechanical perspective on molar emergence and primate life history. SCIENCE ADVANCES 2021; 7:eabj0335. [PMID: 34613774 PMCID: PMC8494445 DOI: 10.1126/sciadv.abj0335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/16/2021] [Indexed: 05/21/2023]
Abstract
The strong relationship between M1 emergence age and life history across primates provides a means of reconstructing fossil life history. The underlying process that leads to varying molar emergence schedules, however, remains elusive. Using three-dimensional data to quantify masticatory form in ontogenetic samples representing 21 primate species, we test the hypothesis that the location and timing of molar emergence are constrained to avoid potentially dangerous distractive forces at the temporomandibular joint (TMJ) throughout growth. We show that (i) molars emerge in a predictable position to safeguard the TMJ, (ii) the rate and duration of jaw growth determine the timing of molar emergence, and (iii) the rate and cessation age of jaw growth is related to life history. Thus, orofacial development is constrained by biomechanics throughout ontogeny. This integrative perspective on primate skull growth is consistent with a long sought-after causal explanation underlying the correlation between molar emergence and life history.
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Affiliation(s)
- Halszka Glowacka
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ 85004, USA
- Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA
- Corresponding author.
| | - Gary T. Schwartz
- Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA
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Brassard C, Merlin M, Monchâtre-Leroy E, Guintard C, Barrat J, Garès H, Larralle A, Triquet R, Houssin C, Callou C, Cornette R, Herrel A. Masticatory system integration in a commensal canid: interrelationships between bones, muscles and bite force in the red fox. J Exp Biol 2021; 224:jeb.224394. [DOI: 10.1242/jeb.224394] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 01/28/2021] [Indexed: 12/20/2022]
Abstract
ABSTRACT
The jaw system in canids is essential for defence and prey acquisition. However, how it varies in wild species in comparison with domestic species remains poorly understood, yet is of interest in terms of understanding the impact of artificial selection. Here, we explored the variability and interrelationships between the upper and lower jaws, muscle architecture and bite force in the red fox (Vulpes vulpes). We performed dissections and used 3D geometric morphometric approaches to quantify jaw shape in 68 foxes. We used a static lever model and bite force estimates were compared with in vivo measurements of 10 silver foxes. Our results show strong relationships exist between cranial and mandible shape, and between cranial or mandible shape on the one hand and muscles or estimated bite force on the other hand, confirming the strong integration of the bony and muscular components of the jaw system. These strong relationships are strongly driven by size. The functional links between shape and estimated bite force are stronger for the mandible, which probably reflects its greater specialisation towards biting. We then compared our results with data previously obtained for dogs (Canis lupus familiaris) to investigate the effect of domestication. Foxes and dogs differ in skull shape and muscle physiological cross-sectional area (PCSA). They show a similar amount of morphological variation in muscle PCSA, but foxes show lower variation in cranial and mandible shape. Interestingly, the patterns of covariation are not stronger in foxes than in dogs, suggesting that domestication did not lead to a disruption of the functional links of the jaw system.
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Affiliation(s)
- Colline Brassard
- Mécanismes Adaptatifs et Evolution (MECADEV), Muséum national d'Histoire naturelle, CNRS, 55 rue Buffon 75005, Paris, France
- Archéozoologie, archéobotanique: sociétés, pratiques et environnements (AASPE), Muséum national d'Histoire naturelle, CNRS, CP55, 57 rue Cuvier, 75005 Paris, France
| | - Marilaine Merlin
- Mécanismes Adaptatifs et Evolution (MECADEV), Muséum national d'Histoire naturelle, CNRS, 55 rue Buffon 75005, Paris, France
| | - Elodie Monchâtre-Leroy
- ANSES, Laboratoire de la rage et de la faune sauvage, Station expérimentale d'Atton, CS 40009, 54220 Malzéville, France
| | - Claude Guintard
- Laboratoire d'Anatomie comparée, Ecole Nationale Vétérinaire, de l'Agroalimentaire et de l'Alimentation, Nantes Atlantique – ONIRIS, Nantes Cedex 03, France
- GEROM, UPRES EA 4658, LABCOM ANR NEXTBONE, Faculté de santé de l'Université d'Angers, 49933 Angers Cedex, France
| | - Jacques Barrat
- ANSES, Laboratoire de la rage et de la faune sauvage, Station expérimentale d'Atton, CS 40009, 54220 Malzéville, France
| | - Hélène Garès
- Direction des Services Vétérinaires – D.D.C.S.P.P. de la Dordogne, 24000 Périgueux, France
| | | | - Raymond Triquet
- Université de Lille III, Domaine Universitaire du Pont de Bois BP 60149, Villeneuve d'ascq Cedex 59653, France
| | - Céline Houssin
- Institut de Systématique, Evolution, Biodiversité (ISYEB), CNRS, Muséum national d'Histoire naturelle, Sorbonne Université, Ecole Pratique des hautes Etudes, Université des Antilles, CNRS, CP 50, 57 rue Cuvier, 75005 Paris, France
| | - Cécile Callou
- Mécanismes Adaptatifs et Evolution (MECADEV), Muséum national d'Histoire naturelle, CNRS, 55 rue Buffon 75005, Paris, France
| | - Raphaël Cornette
- Institut de Systématique, Evolution, Biodiversité (ISYEB), CNRS, Muséum national d'Histoire naturelle, Sorbonne Université, Ecole Pratique des hautes Etudes, Université des Antilles, CNRS, CP 50, 57 rue Cuvier, 75005 Paris, France
| | - Anthony Herrel
- Mécanismes Adaptatifs et Evolution (MECADEV), Muséum national d'Histoire naturelle, CNRS, 55 rue Buffon 75005, Paris, France
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13
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Ingestive behaviors in bearded capuchins (Sapajus libidinosus). Sci Rep 2020; 10:20850. [PMID: 33257755 PMCID: PMC7705727 DOI: 10.1038/s41598-020-77797-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 11/17/2020] [Indexed: 11/25/2022] Open
Abstract
The biomechanical and adaptive significance of variation in craniodental and mandibular morphology in fossil hominins is not always clear, at least in part because of a poor understanding of how different feeding behaviors impact feeding system design (form–function relationships). While laboratory studies suggest that ingestive behaviors produce variable loading, stress, and strain regimes in the cranium and mandible, understanding the relative importance of these behaviors for feeding system design requires data on their use in wild populations. Here we assess the frequencies and durations of manual, ingestive, and masticatory behaviors from more than 1400 observations of feeding behaviors video-recorded in a wild population of bearded capuchins (Sapajus libidinosus) at Fazenda Boa Vista in Piauí, Brazil. Our results suggest that ingestive behaviors in wild Sapajus libidinosus were used for a range of food material properties and typically performed using the anterior dentition. Coupled with previous laboratory work indicating that ingestive behaviors are associated with higher mandibular strain magnitudes than mastication, these results suggest that ingestive behaviors may play an important role in craniodental and mandibular design in capuchins and may be reflected in robust adaptations in fossil hominins.
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Ortiz A, Schander-Triplett K, Bailey SE, Skinner MM, Hublin JJ, Schwartz GT. Enamel thickness variation in the deciduous dentition of extant large-bodied hominoids. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:500-513. [PMID: 32767577 DOI: 10.1002/ajpa.24106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 05/16/2020] [Accepted: 06/11/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVES Enamel thickness features prominently in hominoid evolutionary studies. To date, however, studies of enamel thickness in humans, great apes, and their fossil relatives have focused on the permanent molar row. Comparatively little research effort has been devoted to tissue proportions within deciduous teeth. Here we attempt to fill this gap by documenting enamel thickness variation in the deciduous dentition of extant large-bodied hominoids. MATERIALS AND METHODS We used microcomputed tomography to image dental tissues in 80 maxillary and 78 mandibular deciduous premolars of Homo sapiens, Pan troglodytes, Gorilla, and Pongo. Two-dimensional virtual sections were created from the image volumes to quantify average (AET) and relative (RET) enamel thickness, as well as its distribution across the crown. RESULTS Our results reveal no significant differences in enamel thickness among the great apes. Unlike the pattern present in permanent molars, Pongo does not stand out as having relatively thicker-enameled deciduous premolars than P. troglodytes and Gorilla. Humans, on the other hand, possess significantly thicker deciduous premolar enamel in comparison to great apes. Following expectations from masticatory biomechanics, we also find that the "functional" side (protocone, protoconid) of deciduous premolars generally possesses thicker enamel than the "nonfunctional" side. DISCUSSION Our study lends empirical support to anecdotal observations that patterns of AET and RET observed for permanent molars of large-bodied apes do not apply to deciduous premolars. By documenting enamel thickness variation in hominoid deciduous teeth, this study provides the comparative context to interpret rates and patterns of wear of deciduous teeth and their utility in life history reconstructions.
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Affiliation(s)
- Alejandra Ortiz
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA.,Center for the Study of Human Origins, Department of Anthropology, New York University, New York, New York, USA
| | - Katherine Schander-Triplett
- Barrett, The Honors College, College of Liberal Arts and Sciences, Arizona State University, Tempe, Arizona, USA
| | - Shara E Bailey
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, New York, USA.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew M Skinner
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Collège de France, Paris, France
| | - Gary T Schwartz
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA
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15
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Machado FA. Selection and Constraints in the Ecomorphological Adaptive Evolution of the Skull of Living Canidae (Carnivora, Mammalia). Am Nat 2020; 196:197-215. [PMID: 32673094 DOI: 10.1086/709610] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The association between phenotype and ecology is essential for understanding the environmental drivers of morphological evolution. This is a particularly challenging task when dealing with complex traits, such as the skull, where multiple selective pressures are at play and evolution might be constrained by ontogenetic and genetic factors. I integrate morphometric tools, comparative methods, and quantitative genetics to investigate how ontogenetic constraints and selection might have interacted during the evolution of the skull in extant Canidae. The results confirm that the evolution of cranial morphology was largely adaptive and molded by changes in diet composition. While the investigation of the adaptive landscape reveals two main selective lines of least resistance (one associated with size and one associated with functional shape features), rates of evolution along size were higher than those found for shape dimensions, suggesting the influence of constraints on morphological evolution. Structural modeling analyses revealed that size, which is the line of most genetic/phenotypic variation, might have acted as a constraint, negatively impacting dietary evolution. Constraints might have been overcome in the case of selection for the consumption of large prey by associating strong selection along both size and shape directions. The results obtained here show that microevolutionary constraints may have played a role in shaping macroevolutionary patterns of morphological evolution.
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16
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Edmonds HM, Glowacka H. The ontogeny of maximum bite force in humans. J Anat 2020; 237:529-542. [PMID: 32406523 DOI: 10.1111/joa.13218] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/18/2020] [Accepted: 04/23/2020] [Indexed: 11/27/2022] Open
Abstract
Ontogenetic changes in the human masticatory complex suggest that bite force, a key measure of chewing performance, increases throughout growth and development. Current published bite force values for humans exist for molar and incisal biting, but few studies measure bite forces across all tooth types, or measure bite force potentials in subjects of different ages. In the absence of live data, models of bite force such as the Constrained Lever Model (CLM), are employed to predict bite force at different bite points for adults, but it is unclear whether such a model can accurately predict bite force potentials for juveniles or subadults. This study compares theoretically derived bite forces and live bite force data, and places these within an ontogenetic context in humans. Specifically, we test whether (1) patterns of maximum bite force increase along the tooth row throughout ontogeny, (2) bite force patterns estimated using the CLM match patterns observed from live bite force data, and (3) changes in bite forces along the tooth row and throughout ontogeny are associated with concomitant changes in adductor muscle leverage. Our findings show that maximum bite forces increase throughout ontogeny and change along the tooth row, with the highest forces occurring at the posterior dentition. These findings adhere to the expectations under the CLM and validate the model's utility in predicting bite force values throughout development. Furthermore, adductor muscle leverage values reflect this pattern, with the greatest leverage values occurring at the posterior dentition throughout ontogeny. The CLM informs our study of mammalian chewing mechanics by providing a model of how morphological changes of the masticatory apparatus during ontogeny affect bite force distribution along the tooth row. Furthermore, the decreased bite force magnitudes observed in juveniles and subadults compared with adults suggest that differences in juvenile and subadult diets may partially be due to differences in bite force production potentials.
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Affiliation(s)
- Hallie M Edmonds
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA
| | - Halszka Glowacka
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
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17
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Laird MF, Ross CF, O'Higgins P. Jaw kinematics and mandibular morphology in humans. J Hum Evol 2020; 139:102639. [DOI: 10.1016/j.jhevol.2019.102639] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 07/05/2019] [Accepted: 07/08/2019] [Indexed: 10/25/2022]
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18
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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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19
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The Masticatory Apparatus of Humans (Homo sapiens): Evolution and Comparative Functional Morphology. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/978-3-030-13739-7_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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20
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Kupczik K, Toro-Ibacache V, Macho GA. On the relationship between maxillary molar root shape and jaw kinematics in Australopithecus africanus and Paranthropus robustus. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180825. [PMID: 30225074 PMCID: PMC6124107 DOI: 10.1098/rsos.180825] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/03/2018] [Indexed: 06/08/2023]
Abstract
Plio-Pleistocene hominins from South Africa remain poorly understood. Here, we focus on how Australopithecus africanus and Paranthropus robustus exploited and-in part-partitioned their environment. Specifically, we explore the extent to which first maxillary molar roots (M1) are oriented and thus, by proxy, estimate the direction of loads habitually exerted on the chewing surface. Landmark-based shape analysis of M1 root reconstructions of 26 South African hominins and three East African Paranthropus boisei suggest that A. africanus may have been able to dissipate the widest range of laterally directed loads. Paranthropus robustus and P. boisei, despite having overlapping morphologies, differ in aspects of root shape/size, dento-cranial morphologies, microwear textures and C4 food consumption. Hence, while Paranthropus monophyly cannot be excluded, equivalence of dietary niche can. The South African hominins occupied distinct ecological niches, whereby P. robustus appears uniquely adapted to dissipate antero-posteriorly directed loads.
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Affiliation(s)
- Kornelius Kupczik
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
| | - Viviana Toro-Ibacache
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
- Facultad de Odontología, Universidad de Chile, Sergio Livingstone Pohlhammer 943, Independencia, Región Metropolitana, Santiago de Chile, Chile
| | - Gabriele A. Macho
- School of Archaeology, University of Oxford, Oxford OX1 3QY, UK
- Department of Earth and Planetary Sciences, Birkbeck, University of London, London WC1E 7HX, UK
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21
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Ross CF, Porro LB, Herrel A, Evans SE, Fagan MJ. Bite force and cranial bone strain in four species of lizards. J Exp Biol 2018; 221:jeb.180240. [DOI: 10.1242/jeb.180240] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 10/16/2018] [Indexed: 11/20/2022]
Abstract
In vivo bone strain data provide direct evidence of strain patterns in the cranium during biting. Compared to mammals, in vivo bone strains in lizard skulls are poorly documented. This paper presents strain data from the skulls of Anolis equestris, Gekko gecko, Iguana iguana and Salvator merianae during transducer biting. Analysis of variance was used to investigate effects of bite force, bite point, diet, cranial morphology and cranial kinesis on strain magnitudes. Within individuals the most consistent determinants of variance in bone strain magnitudes are gage location and bite point, with the importance of bite force varying between individuals. Inter-site variance in strain magnitudes—strain gradient—is present in all individuals, and varies with bite point. Between individuals within species, variance in strain magnitude is driven primarily by variation in bite force, not gage location or bite point, suggesting that inter-individual variation in patterns of strain magnitude is minimal. Between species, variation in strain magnitudes is significantly impacted by bite force and species membership, as well as by interactions between gage location, species, and bite point. Independent of bite force, species differences in cranial strain magnitudes may reflect selection for different cranial morphology in relation to feeding function, but what these performance criteria are is not clear. The relatively low strain magnitudes in Iguana and Uromastyx compared to other lizards may be related to their herbivorous diet. Cranial kinesis and the presence or absence of postorbital and supratemporal bars are not important determinants of inter-specific variation in strain magnitudes.
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Affiliation(s)
- Callum F. Ross
- Organismal Biology & Anatomy, University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA
| | - Laura B. Porro
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Anthony Herrel
- Sorbonne Universités, Département Adaptations du Vivant, UMR 7179, C.N.R.S/M.N.H.N., Paris, France
| | - Susan E. Evans
- Department of Cell and Developmental Biology, UCL, University College London, London, WC1E 6BT, UK
| | - Michael J. Fagan
- School of Engineering and Computer Science, University of Hull, Hull, HU6 7RX, UK
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Cox PG. The jaw is a second-class lever in Pedetes capensis (Rodentia: Pedetidae). PeerJ 2017; 5:e3741. [PMID: 28875081 PMCID: PMC5581530 DOI: 10.7717/peerj.3741] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/05/2017] [Indexed: 11/23/2022] Open
Abstract
The mammalian jaw is often modelled as a third-class lever for the purposes of biomechanical analyses, owing to the position of the resultant muscle force between the jaw joint and the teeth. However, it has been proposed that in some rodents the jaws operate as a second-class lever during distal molar bites, owing to the rostral position of the masticatory musculature. In particular, the infraorbital portion of the zygomatico-mandibularis (IOZM) has been suggested to be of major importance in converting the masticatory system from a third-class to a second-class lever. The presence of the IOZM is diagnostic of the hystricomorph rodents, and is particularly well-developed in Pedetes capensis, the South African springhare. In this study, finite element analysis (FEA) was used to assess the lever mechanics of the springhare masticatory system, and to determine the function of the IOZM. An FE model of the skull of P. capensis was constructed and loaded with all masticatory muscles, and then solved for biting at each tooth in turn. Further load cases were created in which each masticatory muscle was removed in turn. The analyses showed that the mechanical advantage of the springhare jaws was above one at all molar bites and very close to one during the premolar bite. Removing the IOZM or masseter caused a drop in mechanical advantage at all bites, but affected strain patterns and cranial deformation very little. Removing the ZM had only a small effect on mechanical advantage, but produced a substantial reduction in strain and deformation across the skull. It was concluded that the masticatory system of P. capensis acts as a second class lever during bites along almost the entire cheek tooth row. The IOZM is clearly a major contributor to this effect, but the masseter also has a part to play. The benefit of the IOZM is that it adds force without substantially contributing to strain or deformation of the skull. This may help explain why the hystricomorphous morphology has evolved multiple times independently within Rodentia.
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Affiliation(s)
- Philip G Cox
- Department of Archaeology, University of York, York, UK.,Hull York Medical School, University of York, York, UK
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Laird MF. Variation in human gape cycle kinematics and occlusal topography. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 164:574-585. [DOI: 10.1002/ajpa.23298] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 07/07/2017] [Accepted: 08/01/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Myra F. Laird
- Department of Organismal Biology and Anatomy; University of Chicago; Chicago Illinois 60637
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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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Reed DA, Iriarte-Diaz J, Diekwisch TGH. A three dimensional free body analysis describing variation in the musculoskeletal configuration of the cynodont lower jaw. Evol Dev 2016; 18:41-53. [PMID: 26763591 DOI: 10.1111/ede.12171] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The evolution of the middle ear from the cynodont craniomandibular bones is one of the key mammalian innovations, and the mechanics underlying this anatomical transformation represents an intriguing paradox. Because the jaw joint of nonmammalian cynodonts was functionally coupled to the inner ear, auditory performance would favor low joint reaction forces. However, this could not be achieved at the expense of feeding performance, favoring high bite forces. The balance of these two seemingly incompatible performance criteria in the context of the morphological diversity of the cynodont lower jaw is poorly understood. Here we derive a series of equations using three dimensional free body analysis that describe the relationship between the orientation and position of the jaw elevator muscles, the position of the jaw articulation relative to the bite point, the joint reaction forces and the bite force in the lower jaw of the nonmammalian cynodont Probainognathus. These equations permit the effects of variation in each variable to be tested independently, yielding three terms that act to limit joint reaction forces without substantially impacting bite force: the reorientation of the resultant muscle force more vertically, shifting the position of the bite point medial to the jaw articulation, and elevating the jaw articulation above the level with the tooth row only when the muscles are oriented principally in the anterior direction. The predictions from our equations provide insights for functional interpretations of patterns of morphological diversity in the cynodont fossil record. They also illustrate that the musculoskeletal configuration of the cynodont lower jaw can be evolutionarily labile without negatively impacting the dual performance criteria of the auditory and feeding system.
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Affiliation(s)
- D A Reed
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - J Iriarte-Diaz
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - T G H Diekwisch
- Center for Craniofacial Research and Diagnosis and Department of Periodontics, Baylor College of Dentistry, Dallas, TX, USA
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Ledogar JA, Dechow PC, Wang Q, Gharpure PH, Gordon AD, Baab KL, Smith AL, Weber GW, Grosse IR, Ross CF, Richmond BG, Wright BW, Byron C, Wroe S, Strait DS. Human feeding biomechanics: performance, variation, and functional constraints. PeerJ 2016; 4:e2242. [PMID: 27547550 PMCID: PMC4975005 DOI: 10.7717/peerj.2242] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/21/2016] [Indexed: 11/20/2022] Open
Abstract
The evolution of the modern human (Homo sapiens) cranium is characterized by a reduction in the size of the feeding system, including reductions in the size of the facial skeleton, postcanine teeth, and the muscles involved in biting and chewing. The conventional view hypothesizes that gracilization of the human feeding system is related to a shift toward eating foods that were less mechanically challenging to consume and/or foods that were processed using tools before being ingested. This hypothesis predicts that human feeding systems should not be well-configured to produce forceful bites and that the cranium should be structurally weak. An alternate hypothesis, based on the observation that humans have mechanically efficient jaw adductors, states that the modern human face is adapted to generate and withstand high biting forces. We used finite element analysis (FEA) to test two opposing mechanical hypotheses: that compared to our closest living relative, chimpanzees (Pan troglodytes), the modern human craniofacial skeleton is (1) less well configured, or (2) better configured to generate and withstand high magnitude bite forces. We considered intraspecific variation in our examination of human feeding biomechanics by examining a sample of geographically diverse crania that differed notably in shape. We found that our biomechanical models of human crania had broadly similar mechanical behavior despite their shape variation and were, on average, less structurally stiff than the crania of chimpanzees during unilateral biting when loaded with physiologically-scaled muscle loads. Our results also show that modern humans are efficient producers of bite force, consistent with previous analyses. However, highly tensile reaction forces were generated at the working (biting) side jaw joint during unilateral molar bites in which the chewing muscles were recruited with bilateral symmetry. In life, such a configuration would have increased the risk of joint dislocation and constrained the maximum recruitment levels of the masticatory muscles on the balancing (non-biting) side of the head. Our results do not necessarily conflict with the hypothesis that anterior tooth (incisors, canines, premolars) biting could have been selectively important in humans, although the reduced size of the premolars in humans has been shown to increase the risk of tooth crown fracture. We interpret our results to suggest that human craniofacial evolution was probably not driven by selection for high magnitude unilateral biting, and that increased masticatory muscle efficiency in humans is likely to be a secondary byproduct of selection for some function unrelated to forceful biting behaviors. These results are consistent with the hypothesis that a shift to softer foods and/or the innovation of pre-oral food processing techniques relaxed selective pressures maintaining craniofacial features that favor forceful biting and chewing behaviors, leading to the characteristically small and gracile faces of modern humans.
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Affiliation(s)
- Justin A. Ledogar
- Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
- Department of Anthropology, State University of New York at Albany, Albany, New York, United States
| | - Paul C. Dechow
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, United States
| | - Qian Wang
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, United States
| | - Poorva H. Gharpure
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, United States
| | - Adam D. Gordon
- Department of Anthropology, State University of New York at Albany, Albany, New York, United States
| | - Karen L. Baab
- Department of Anatomy, Midwestern University, Glendale, Arizona, United States
| | - Amanda L. Smith
- Department of Anthropology, State University of New York at Albany, Albany, New York, United States
- Department of Anthropology, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Gerhard W. Weber
- Department of Anthropology, University of Vienna, Vienna, Austria
| | - Ian R. Grosse
- Department of Mechanical & Industrial Engineering, University of Massachusetts, Amherst, Massachusetts, United States
| | - Callum F. Ross
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, Illinois, United States
| | - Brian G. Richmond
- Division of Anthropology, American Museum of Natural History, New York, New York, United States
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Barth W. Wright
- Department of Anatomy, Kansas City University of Medicine and Biosciences, Kansas City, Missouri, United States
| | - Craig Byron
- Department of Biology, Mercer University, Macon, Georgia, United States
| | - Stephen Wroe
- Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| | - David S. Strait
- Department of Anthropology, State University of New York at Albany, Albany, New York, United States
- Department of Anthropology, Washington University in St. Louis, St. Louis, Missouri, United States
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Santana SE, Miller KE. Extreme Postnatal Scaling in Bat Feeding Performance: A View of Ecomorphology from Ontogenetic and Macroevolutionary Perspectives. Integr Comp Biol 2016; 56:459-68. [DOI: 10.1093/icb/icw075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Dunham NT, Lambert AL. The role of leaf toughness on foraging efficiency in Angola black and white colobus monkeys (Colobus angolensis palliatus). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 161:343-54. [DOI: 10.1002/ajpa.23036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/05/2016] [Accepted: 06/07/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Noah T. Dunham
- Department of Anthropology; The Ohio State University; Columbus OH 43210
| | - Alexander L. Lambert
- Engineering Department; Star Dynamics Corporation; 4455 Reynolds Dr Hilliard Ohio 43026
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Toro-Ibacache V, O'Higgins P. The Effect of Varying Jaw-elevator Muscle Forces on a Finite Element Model of a Human Cranium. Anat Rec (Hoboken) 2016; 299:828-39. [PMID: 27111484 DOI: 10.1002/ar.23358] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 02/22/2016] [Accepted: 03/08/2016] [Indexed: 11/07/2022]
Abstract
Finite element analyses simulating masticatory system loading are increasingly undertaken in primates, hominin fossils and modern humans. Simplifications of models and loadcases are often required given the limits of data and technology. One such area of uncertainty concerns the forces applied to cranial models and their sensitivity to variations in these forces. We assessed the effect of varying force magnitudes among jaw-elevator muscles applied to a finite element model of a human cranium. The model was loaded to simulate incisor and molar bites using different combinations of muscle forces. Symmetric, asymmetric, homogeneous, and heterogeneous muscle activations were simulated by scaling maximal forces. The effects were compared with respect to strain distribution (i.e., modes of deformation) and magnitudes; bite forces and temporomandibular joint (TMJ) reaction forces. Predicted modes of deformation, strain magnitudes and bite forces were directly proportional to total applied muscle force and relatively insensitive to the degree of heterogeneity of muscle activation. However, TMJ reaction forces and mandibular fossa strains decrease and increase on the balancing and working sides according to the degree of asymmetry of loading. These results indicate that when modes, rather than magnitudes, of facial deformation are of interest, errors in applied muscle forces have limited effects. However the degree of asymmetric loading does impact on TMJ reaction forces and mandibular fossa strains. These findings are of particular interest in relation to studies of skeletal and fossil material, where muscle data are not available and estimation of muscle forces from skeletal proxies is prone to error. Anat Rec, 299:828-839, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Viviana Toro-Ibacache
- Centre for Anatomical and Human Sciences, Department of Archaeology and Hull York Medical School, University of York, Heslington, York, YO10 5DD, UK
- Facultad De Odontología, Universidad De Chile, Sergio Livingstone Pohlhammer 943, Independencia, Región Metropolitana, Chile
| | - Paul O'Higgins
- Centre for Anatomical and Human Sciences, Department of Archaeology and Hull York Medical School, University of York, Heslington, York, YO10 5DD, UK
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Evans AR, Daly ES, Catlett KK, Paul KS, King SJ, Skinner MM, Nesse HP, Hublin JJ, Townsend GC, Schwartz GT, Jernvall J. A simple rule governs the evolution and development of hominin tooth size. Nature 2016; 530:477-80. [DOI: 10.1038/nature16972] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 01/07/2016] [Indexed: 11/09/2022]
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Mechanical evidence that Australopithecus sediba was limited in its ability to eat hard foods. Nat Commun 2016; 7:10596. [PMID: 26853550 PMCID: PMC4748115 DOI: 10.1038/ncomms10596] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 01/04/2016] [Indexed: 11/09/2022] Open
Abstract
Australopithecus sediba has been hypothesized to be a close relative of the genus Homo. Here we show that MH1, the type specimen of A. sediba, was not optimized to produce high molar bite force and appears to have been limited in its ability to consume foods that were mechanically challenging to eat. Dental microwear data have previously been interpreted as indicating that A. sediba consumed hard foods, so our findings illustrate that mechanical data are essential if one aims to reconstruct a relatively complete picture of feeding adaptations in extinct hominins. An implication of our study is that the key to understanding the origin of Homo lies in understanding how environmental changes disrupted gracile australopith niches. Resulting selection pressures led to changes in diet and dietary adaption that set the stage for the emergence of our genus. Dietary adaptations of extinct early humans are often inferred from dental microwear data. Here, the authors employ mechanical analyses to show that Australopithecus sediba had limited ability to consume hard foods.
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The relationship between skull morphology, masticatory muscle force and cranial skeletal deformation during biting. Ann Anat 2016; 203:59-68. [DOI: 10.1016/j.aanat.2015.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/27/2015] [Accepted: 03/01/2015] [Indexed: 11/21/2022]
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Singleton M. Functional geometric morphometric analysis of masticatory system ontogeny in papionin primates. Anat Rec (Hoboken) 2015; 298:48-63. [PMID: 25338826 DOI: 10.1002/ar.23068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 10/11/2014] [Indexed: 11/05/2022]
Abstract
The three-dimensional configuration of the primate masticatory system is constrained by the need to maximize bite forces while avoiding distraction of the temporomandibular joint (TMJ). Within these bounds, shape variation has predictable effects on functional capacities such as mechanical advantage and gape. In this study, geometric morphometric analysis is used to investigate the ontogeny of masticatory function in papionin monkeys and test the hypothesis that biomechanical constraints determine the location of molar eruption. This "constrained eruption hypothesis" predicts that the distalmost molar (DMX) will occupy a consistent location anterior to the TMJ and that jaw adductor muscles will maintain consistent positions relative to both DMX and TMJ. Craniometric landmarks were digitized on cross-sectional ontogenetic series of nine papionin species. Form-space PCA of Procrustes residuals, visualization of Bookstein shape coordinates, and nonparametric ANOVA were used to identify ontogenetic shape trends and test for significant ontogenetic changes in relative landmark positions. In most taxa, DMX maintains a consistent position relative to the TMJ while the anterior dentition migrates anteriorly. Where significant intraspecific ontogenetic differences occur, they involve anterior migration of DMX in later dental stages, likely due to late adolescent growth of the posterior palate. Attachments of the anterior temporalis and deep masseter also maintain consistent positions relative to the TMJ; however, the superficial masseter migrates anteriorly throughout ontogeny. All muscle attachments migrate laterally relative to the TMJ, reflecting positive scaling of adductor PCSA. Overall, results support the constrained eruption hypothesis and suggest mechanisms by which functional capacity is maintained during ontogeny.
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Affiliation(s)
- Michelle Singleton
- Department of Anatomy, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, Illinois
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Santana SE. Quantifying the effect of gape and morphology on bite force: biomechanical modelling and
in vivo
measurements in bats. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12522] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sharlene E. Santana
- Department of Biology and Burke Museum of Natural History and Culture University of Washington Box 315800 Seattle WA 98195‐1800USA
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35
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Self CJ. Dental root size in bats with diets of different hardness. J Morphol 2015; 276:1065-74. [PMID: 26011087 DOI: 10.1002/jmor.20400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 03/23/2015] [Accepted: 04/27/2015] [Indexed: 11/06/2022]
Abstract
The relationship between tooth roots and diet is relatively unexplored, although a logical relationship between harder diets and increased root surface area (RSA) is suggested. This study addresses the interaction between tooth morphology, diet, and bite force in small mammals, phyllostomid bats. Using micro computed tomography (microCT), tooth root morphology of two fruit-eating species (Carollia perspicillata and Chiroderma villosum) and two insect-eating species (Mimon bennettii and Macrotus californicus) was compared. These species did not differ in skull or estimated body size. Food hardness, rather than dietary classification, proved to be the strongest grouping factor, with the two insectivores and the seed-processing frugivore (C. villosum) having significantly larger RSAs. Bite force was estimated using skull measurements; bite force significantly correlated with tooth RSA but not with body size. Although the three durophagous species did exhibit larger crowns, the area of the occlusal surface did not vary among the four species. There was a linear relationship between root size and crown size, indicating that the roots were not expanded disproportionately; instead the entire tooth was larger in the hard diet species. MicroCT allows the nondestructive quantification of previously difficult-to-access tooth morphology; this method shows the potential for tooth roots to provide valuable dietary, behavioral, and ecological information in small mammals. J. Morphol. 276:1065-1074, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Casey J Self
- Department of Biology, University of Washington, Seattle, Washington
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36
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Abstract
Feeding is the set of behaviors whereby organisms acquire and process the energy required for survival and reproduction. Thus, feeding system morphology is presumably subject to selection to maintain or improve feeding performance. Relationships among feeding system morphology, feeding behavior, and diet not only explain the morphological diversity of extant primates, but can also be used to reconstruct feeding behavior and diet in fossil taxa. Dental morphology has long been known to reflect aspects of feeding behavior and diet but strong relationships of craniomandibular morphology to feeding behavior and diet have yet to be defined.
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Smith AL, Benazzi S, Ledogar JA, Tamvada K, Pryor Smith LC, Weber GW, Spencer MA, Lucas PW, Michael S, Shekeban A, Al-Fadhalah K, Almusallam AS, Dechow PC, Grosse IR, Ross CF, Madden RH, Richmond BG, Wright BW, Wang Q, Byron C, Slice DE, Wood S, Dzialo C, Berthaume MA, Casteren AV, Strait DS. The feeding biomechanics and dietary ecology of Paranthropus boisei. Anat Rec (Hoboken) 2015; 298:145-67. [PMID: 25529240 PMCID: PMC4420635 DOI: 10.1002/ar.23073] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/03/2014] [Accepted: 10/11/2014] [Indexed: 11/09/2022]
Abstract
The African Plio-Pleistocene hominins known as australopiths evolved derived craniodental features frequently interpreted as adaptations for feeding on either hard, or compliant/tough foods. Among australopiths, Paranthropus boisei is the most robust form, exhibiting traits traditionally hypothesized to produce high bite forces efficiently and strengthen the face against feeding stresses. However, recent mechanical analyses imply that P. boisei may not have been an efficient producer of bite force and that robust morphology in primates is not necessarily strong. Here we use an engineering method, finite element analysis, to show that the facial skeleton of P. boisei is structurally strong, exhibits a strain pattern different from that in chimpanzees (Pan troglodytes) and Australopithecus africanus, and efficiently produces high bite force. It has been suggested that P. boisei consumed a diet of compliant/tough foods like grass blades and sedge pith. However, the blunt occlusal topography of this and other species suggests that australopiths are adapted to consume hard foods, perhaps including grass and sedge seeds. A consideration of evolutionary trends in morphology relating to feeding mechanics suggests that food processing behaviors in gracile australopiths evidently were disrupted by environmental change, perhaps contributing to the eventual evolution of Homo and Paranthropus.
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Affiliation(s)
- Amanda L. Smith
- Department of Anthropology, University at Albany, Albany, New York
| | - Stefano Benazzi
- Department of Cultural Heritage, University of Bologna, Via degli Ariani 1, Ravenna 48121, Italy
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | | | - Kelli Tamvada
- Department of Anthropology, University at Albany, Albany, New York
| | - Leslie C. Pryor Smith
- Department of Biomedical Sciences, Texas A&M University, Baylor College of Dentistry, Dallas, Texas
| | - Gerhard W. Weber
- Department of Anthropology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria
| | - Mark A. Spencer
- School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona
- Department of Biology, South Mountain Community College, Phoenix, Arizona
| | - Peter W. Lucas
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Safat 13110, Kuwait
| | - Shaji Michael
- Nanotechnology Research Facility, College of Engineering and Petroleum, Kuwait University, Safat 13060, Kuwait
| | - Ali Shekeban
- Nanotechnology Research Facility, College of Engineering and Petroleum, Kuwait University, Safat 13060, Kuwait
| | - Khaled Al-Fadhalah
- Department of Mechanical Engineering, College of Engineering and Petroleum, Kuwait University, Safat 13060, Kuwait
| | - Abdulwahab S. Almusallam
- Department of Chemical Engineering, College of Engineering and Petroleum, Kuwait University, Safat 13060, Kuwait
| | - Paul C. Dechow
- Department of Biomedical Sciences, Texas A&M University, Baylor College of Dentistry, Dallas, Texas
| | - Ian R. Grosse
- Department of Mechanical & Industrial Engineering, University of Massachusetts, Amherst, Massachusetts
| | - Callum F. Ross
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, Illinois
| | - Richard H. Madden
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, Illinois
| | - Brian G. Richmond
- Center for the Advanced Study of Hominid Paleobiology, Department of Anthropology, The George Washington University, NW, Washington, District of Columbia
- Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia
- Division of Anthropology, American Museum of Natural History, New York, New York
| | - Barth W. Wright
- Department of Anatomy, Kansas City University of Medicine and Biosciences, Kansas City, Missouri
| | - Qian Wang
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, Georgia
| | - Craig Byron
- Department of Biology, Mercer University, Macon, Georgia
| | - Dennis E. Slice
- Department of Anthropology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria
- School of Computational Science & Department of Biological Science, Florida State University, Dirac Science Library, Tallahassee, Florida
| | - Sarah Wood
- Department of Mechanical & Industrial Engineering, University of Massachusetts, Amherst, Massachusetts
| | - Christine Dzialo
- Department of Mechanical & Industrial Engineering, University of Massachusetts, Amherst, Massachusetts
| | - Michael A. Berthaume
- Department of Anthropology, University of Massachusetts, Amherst, Massachusetts
- Medical and Biological Engineering Research Group, Department of Engineering, University of Hull, Cottingham Road, Kingston-Upon-Hull, HU6 7RX, United Kingdom
| | - Adam Van Casteren
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Safat 13110, Kuwait
- Max Planck Weizman Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
| | - David S. Strait
- Department of Anthropology, University at Albany, Albany, New York
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Kuć J, Sierpińska T, Gołębiewska M. The relationship between facial morphology and the structure of the alveolar part of the mandible in edentulous complete denture wearers. A preliminary study. Acta Odontol Scand 2015; 73:57-66. [PMID: 25183253 DOI: 10.3109/00016357.2014.950181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Although the effect of involutional processes that occurs in the maxilla and mandible of edentulous subjects is obvious, the problem of factors definitely determining the direction of changes still remains unsolved. This study was aimed at determining the relationship between facial morphology and the structure of the alveolar part and the body of the mandible in edentulous complete denture wearers. MATERIALS AND METHODS Twenty-five healthy edentulous Caucasian patients in the 70.5 ± 9 years of age group were examined. All patients underwent tele-X-ray examination with the presence of currently used dentures in the oral cavity. To assess morphological parameters of the facial skeleton, cephalograms were analyzed according to Ricketts and Mc Namara method. To assess the mandible morphology, the films were measured using the method of Tallgren. RESULTS The period of edentulism was found to be negatively correlated with the anterior segment of the body of the mandible within its symphysis. The parameter corresponding to the location of the first lower molar showed a directly proportional correlation with G'-Sn', G'-Me', Sn'-Me', N-Ans, N-Me, Ans-Me, Co-Gn and Co-Go. Positive correlations were found between the parameters describing contour of the alveolar part of the body of the mandible and mandibular symphysis and G'-Me', Sn'-Me', N-Me, Ans-Me describing the height of the occlusal vertical dimension. CONCLUSION The study showed a directly proportional correlation between the vertical occlusal dimension of the lower face conditioned by prosthetic rehabilitation and the height of the alveolar part in the lateral regions of the mandible.
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Affiliation(s)
- Joanna Kuć
- Department of Prosthodontics, Medical University of Bialystok , Poland
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40
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Miyaoka Y, Ashida I, Iwamori H, Kawakami SY, Tamaki Y, Yamazaki T, Ito N. Synchronization of masseter activity patterns between the right and left sides during chewing in healthy young males. J Med Eng Technol 2014; 38:281-5. [PMID: 24874711 DOI: 10.3109/03091902.2014.916356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Masseter activity patterns during chewing, which were quantitatively assessed using T50 values, were compared between the right and left sides of healthy young males. Surface electromyograms were recorded from both masseters, and each participant was asked to chew four different agar samples at his own pace across two separate sessions. The four agar samples, each possessing differing textural properties, consisted of two normal and two distinctive agar varieties. The Pearson's correlation coefficient was calculated for each pair of T50 values to evaluate the degree of synchronization of activity patterns between both masseters. A three-way analysis of variance revealed significant main effects of the 'participant' and 'experimental session' factors, but not of the 'test food'. The number of significant coefficients increased stepwise by increasing the number of chews per sequence. These results suggest the importance of the initial stages of chewing sequences in facilitating the synchronization of bilateral masseter activity patterns.
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Affiliation(s)
- Yozo Miyaoka
- Department of Health and Nutrition, Niigata University of Health and Welfare , 1398 Shimami-cho, Kita-ku, Niigata 950-3198 , Japan and
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Eng CM, Lieberman DE, Zink KD, Peters MA. Bite force and occlusal stress production in hominin evolution. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 151:544-57. [DOI: 10.1002/ajpa.22296] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 04/24/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Carolyn M. Eng
- Department of Human Evolutionary Biology; Harvard University; Cambridge; MA; 02138
| | - Daniel E. Lieberman
- Department of Human Evolutionary Biology; Harvard University; Cambridge; MA; 02138
| | - Katherine D. Zink
- Department of Human Evolutionary Biology; Harvard University; Cambridge; MA; 02138
| | - Michael A. Peters
- Department of Human Evolutionary Biology; Harvard University; Cambridge; MA; 02138
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Terhune CE. How Effective Are Geometric Morphometric Techniques for Assessing Functional Shape Variation? An Example From the Great Ape Temporomandibular Joint. Anat Rec (Hoboken) 2013; 296:1264-82. [DOI: 10.1002/ar.22724] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 04/28/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Claire E. Terhune
- Department of Community and Family Medicine; Duke University Medical Center; Durham North Carolina
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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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Le Cabec A, Gunz P, Kupczik K, Braga J, Hublin JJ. Anterior tooth root morphology and size in Neanderthals: Taxonomic and functional implications. J Hum Evol 2013; 64:169-93. [DOI: 10.1016/j.jhevol.2012.08.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 08/03/2012] [Accepted: 08/08/2012] [Indexed: 01/18/2023]
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Morse PE, Daegling DJ, McGraw WS, Pampush JD. Dental wear among cercopithecid monkeys of the Taï forest, Côte d'Ivoire. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 150:655-65. [DOI: 10.1002/ajpa.22242] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 01/17/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Paul E. Morse
- Department of Anthropology; University of Florida; Gainesville; FL
| | | | - W. Scott McGraw
- Department of Anthropology; The Ohio State University; Columbus; OH
| | - James D. Pampush
- Department of Anthropology; University of Florida; Gainesville; FL
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Chazeau C, Marchal J, Hackert R, Perret M, Herrel A. Proximate determinants of bite force capacity in the mouse lemur. J Zool (1987) 2012. [DOI: 10.1111/jzo.12011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- C. Chazeau
- Département d'Ecologie et de Gestion de la Biodiversité; UMR 7179 C.N.R.S/M.N.H.N.; Paris Cedex 5 France
| | - J. Marchal
- Département d'Ecologie et de Gestion de la Biodiversité; UMR 7179 C.N.R.S/M.N.H.N.; Paris Cedex 5 France
| | - R. Hackert
- Département d'Ecologie et de Gestion de la Biodiversité; UMR 7179 C.N.R.S/M.N.H.N.; Paris Cedex 5 France
| | - M. Perret
- Département d'Ecologie et de Gestion de la Biodiversité; UMR 7179 C.N.R.S/M.N.H.N.; Paris Cedex 5 France
| | - A. Herrel
- Département d'Ecologie et de Gestion de la Biodiversité; UMR 7179 C.N.R.S/M.N.H.N.; Paris Cedex 5 France
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48
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Tooth Root Morphology in the Early Pliocene African Bear Agriotherium africanum (Mammalia, Carnivora, Ursidae) and its Implications for Feeding Ecology. J MAMM EVOL 2012. [DOI: 10.1007/s10914-012-9218-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Makedonska J, Wright BW, Strait DS. The effect of dietary adaption on cranial morphological integration in capuchins (order Primates, genus Cebus). PLoS One 2012; 7:e40398. [PMID: 23110039 PMCID: PMC3482247 DOI: 10.1371/journal.pone.0040398] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 06/08/2012] [Indexed: 01/21/2023] Open
Abstract
A fundamental challenge of morphology is to identify the underlying evolutionary and developmental mechanisms leading to correlated phenotypic characters. Patterns and magnitudes of morphological integration and their association with environmental variables are essential for understanding the evolution of complex phenotypes, yet the nature of the relevant selective pressures remains poorly understood. In this study, the adaptive significance of morphological integration was evaluated through the association between feeding mechanics, ingestive behavior and craniofacial variation. Five capuchin species were examined, Cebus apella sensu stricto, Cebus libidinosus, Cebus nigritus, Cebus olivaceus and Cebus albifrons. Twenty three-dimensional landmarks were chosen to sample facial regions experiencing high strains during feeding, characteristics affecting muscular mechanical advantage and basicranial regions. Integration structure and magnitude between and within the oral and zygomatic subunits, between and within blocks maximizing modularity and within the face, the basicranium and the cranium were examined using partial-least squares, eigenvalue variance, integration indices compared inter-specifically at a common level of sampled population variance and cluster analyses. Results are consistent with previous findings reporting a relative constancy of facial and cranial correlation patterns across mammals, while covariance magnitudes vary. Results further suggest that food material properties structure integration among functionally-linked facial elements and possibly integration between the face and the basicranium. Hard-object-feeding capuchins, especially C. apella s.s., whose faces experience particularly high biomechanical loads are characterized by higher facial and cranial integration especially compared to C. albifrons, likely because morphotypes compromising feeding performance are selected against in species relying on obdurate fallback foods. This is the first study to report a link between food material properties and facial and cranial integration. Furthermore, results do not identify the consistent presence of cranial modules yielding support to suggestions that despite the distinct embryological imprints of its elements the cranium of placental mammals is not characterized by a modular architecture.
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Affiliation(s)
- Jana Makedonska
- Department of Anthropology, University at Albany, Albany, New York, United States of America.
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Fitton LC, Shi JF, Fagan MJ, O'Higgins P. Masticatory loadings and cranial deformation in Macaca fascicularis: a finite element analysis sensitivity study. J Anat 2012; 221:55-68. [PMID: 22690885 DOI: 10.1111/j.1469-7580.2012.01516.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Biomechanical analyses are commonly conducted to investigate how craniofacial form relates to function, particularly in relation to dietary adaptations. However, in the absence of corresponding muscle activation patterns, incomplete muscle data recorded experimentally for different individuals during different feeding tasks are frequently substituted. This study uses finite element analysis (FEA) to examine the sensitivity of the mechanical response of a Macaca fascicularis cranium to varying muscle activation patterns predicted via multibody dynamic analysis. Relative to the effects of varying bite location, the consequences of simulated variations in muscle activation patterns and of the inclusion/exclusion of whole muscle groups were investigated. The resulting cranial deformations were compared using two approaches; strain maps and geometric morphometric analyses. The results indicate that, with bite force magnitude controlled, the variations among the mechanical responses of the cranium to bite location far outweigh those observed as a consequence of varying muscle activations. However, zygomatic deformation was an exception, with the activation levels of superficial masseter being most influential in this regard. The anterior portion of temporalis deforms the cranial vault, but the remaining muscles have less profound effects. This study for the first time systematically quantifies the sensitivity of an FEA model of a primate skull to widely varying masticatory muscle activations and finds that, with the exception of the zygomatic arch, reasonable variants of muscle loading for a second molar bite have considerably less effect on cranial deformation and the resulting strain map than does varying molar bite point. The implication is that FEA models of biting crania will generally produce acceptable estimates of deformation under load as long as muscle activations and forces are reasonably approximated. In any one FEA study, the biological significance of the error in applied muscle forces is best judged against the magnitude of the effect that is being investigated.
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Affiliation(s)
- L C Fitton
- Centre for Anatomical and Human Sciences, Hull York Medical School, University of York, UK.
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