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Scott BR, Brainerd EL, Wilga CAD. Long-Axis Rotation of Jaws of Bamboo Sharks ( Chiloscyllium plagiosum) During Suction Feeding. Integr Org Biol 2022; 4:obac024. [PMID: 35899093 PMCID: PMC9314715 DOI: 10.1093/iob/obac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 05/13/2022] [Indexed: 11/12/2022] Open
Abstract
Synopsis
Long-axis rotation (LAR) of the jaws may be an important component of vertebrate feeding mechanisms, as it has been hypothesized to occur during prey capture or food processing across diverse vertebrate groups including mammals, ray-finned fishes, and sharks and rays. LAR can affect tooth orientation as well as muscle fiber direction and therefore muscle power during feeding. However, to date only a handful of studies have demonstrated this LAR in vivo. Here, we use XROMM to document LAR of the upper and lower jaws in white-spotted bamboo sharks, Chiloscyllium plagiosum, during suction feeding. As the lower jaw begins to depress for suction expansion, both the upper jaw (palatoquadrate) and lower jaw (Meckel's cartilage) evert, such that their toothed surfaces move laterally, and then they invert with jaw closing. Eversion has been shown to tense the dental ligament and erect the teeth in some sharks, but it is not clear how this tooth erection would contribute to suction feeding in bamboo sharks. Two recent XROMM studies have shown LAR of the lower jaws during mastication in mammals and stingrays and our study extends LAR to suction feeding and confirms its presence in shark species. Examples of LAR of the jaws are becoming increasingly widespread across vertebrates with unfused mandibular symphyses. Unfused lower jaws are the plesiomorphic condition for most vertebrate lineages and therefore LAR may be a common component of jaw mechanics unless the mandibular symphysis is fused.
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Affiliation(s)
- Bradley R Scott
- Department of Evolution, Ecology, and Behavior, University of Illinois Urbana-Champaign , 61801 IL , USA
- College of the Environment and Life Sciences, University of Rhode Island , Kingston, 02881 RI , USA
| | - Elizabeth L Brainerd
- Department of Ecology, Evolution, and Organismal Biology, Brown University , 02912 RI , USA
| | - Cheryl A D Wilga
- College of the Environment and Life Sciences, University of Rhode Island , Kingston, 02881 RI , USA
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2
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Cost IN, Sellers KC, Rozin RE, Spates AT, Middleton KM, Holliday CM. 2D and 3D visualizations of archosaur jaw muscle mechanics, ontogeny and phylogeny using ternary diagrams and 3D modeling. J Exp Biol 2022; 225:274255. [PMID: 35119075 DOI: 10.1242/jeb.243216] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/20/2021] [Indexed: 12/16/2022]
Abstract
Comparing patterns of performance and kinematics across behavior, development and phylogeny is crucial to understand the evolution of complex musculoskeletal systems such as the feeding apparatus. However, conveying 3D spatial data of muscle orientation throughout a feeding cycle, ontogenetic pathway or phylogenetic lineage is essential to understanding the function and evolution of the skull in vertebrates. Here, we detail the use of ternary plots for displaying and comparing the 3D orientation of muscle data. First, we illustrate changes in 3D jaw muscle resultants during jaw closing taxa the American alligator (Alligator mississippiensis). Second, we show changes in 3D muscle resultants of jaw muscles across an ontogenetic series of alligators. Third, we compare 3D resultants of jaw muscles of avian-line dinosaurs, including extant (Struthio camelus, Gallus gallus, Psittacus erithacus) and extinct (Tyrannosaurus rex) species to outline the reorganization of jaw muscles that occurred along the line to modern birds. Finally, we compare 3D resultants of jaw muscles of the hard-biting species in our sample (A. mississippiensis, T. rex, P. erithacus) to illustrate how disparate jaw muscle resultants are employed in convergent behaviors in archosaurs. Our findings show that these visualizations of 3D components of jaw muscles are immensely helpful towards identifying patterns of cranial performance, growth and diversity. These tools will prove useful for testing other hypotheses in functional morphology, comparative biomechanics, ecomorphology and organismal evolution.
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Affiliation(s)
- Ian N Cost
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA.,Department of Biology, Albright College, Reading, PA 19612, USA
| | - Kaleb C Sellers
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA.,Department of Clinical Anatomy and OPP, Rocky Vista University, Parker, CO 80134, USA
| | - Rachel E Rozin
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA.,Florida Aquarium, Tampa, FL 33602, USA
| | - Anthony T Spates
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA.,University of Missouri Kansas City School of Dentistry, Kansas City, MO 64108, USA
| | - Kevin M Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA
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3
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Jones MEH, Lucas PW, Tucker AS, Watson AP, Sertich JJW, Foster JR, Williams R, Garbe U, Bevitt JJ, Salvemini F. Neutron scanning reveals unexpected complexity in the enamel thickness of an herbivorous Jurassic reptile. J R Soc Interface 2019; 15:rsif.2018.0039. [PMID: 29899156 PMCID: PMC6030635 DOI: 10.1098/rsif.2018.0039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/18/2018] [Indexed: 11/12/2022] Open
Abstract
Eilenodontines are one of the oldest radiation of herbivorous lepidosaurs (snakes, lizards and tuatara) characterized by batteries of wide teeth with thick enamel that bear mammal-like wear facets. Unlike most reptiles, eilenodontines have limited tooth replacement, making dental longevity particularly important to them. We use both X-ray and neutron computed tomography to examine a fossil tooth from the eilenodontine Eilenodon (Late Jurassic, USA). Of the two approaches, neutron tomography was more successful and facilitated measurements of enamel thickness and distribution. We find the enamel thickness to be regionally variable, thin near the cusp tip (0.10 mm) but thicker around the base (0.15–0.30 mm) and notably greater than that of other rhynchocephalians such as the extant Sphenodon (0.08–0.14 mm). The thick enamel in Eilenodon would permit greater loading, extend tooth lifespan and facilitate the establishment of wear facets that have sharp edges for orally processing plant material such as horsetails (Equisetum). The shape of the enamel dentine junction indicates that tooth development in Eilenodon and Sphenodon involved similar folding of the epithelium but different ameloblast activity.
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Affiliation(s)
- Marc E H Jones
- Department of Earth Sciences, The Natural History Museum, London, UK .,Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,South Australian Museum, North Terrace, Adelaide, South Australia 5001, Australia
| | - Peter W Lucas
- Smithsonian Tropical Research Institute, Balboa, Panama
| | - Abigail S Tucker
- Craniofacial Development and Stem Cell Biology, King's College London, London, UK
| | - Amy P Watson
- Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Joseph J W Sertich
- Department of Earth Sciences, Denver Museum of Nature and Science, Denver, CO, USA
| | | | - Ruth Williams
- Department of Adelaide Microscopy, The University of Adelaide, Adelaide, South Australia 5001, Australia
| | - Ulf Garbe
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | - Joseph J Bevitt
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | - Floriana Salvemini
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
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4
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Cost IN, Middleton KM, Sellers KC, Echols MS, Witmer LM, Davis JL, Holliday CM. Palatal Biomechanics and Its Significance for Cranial Kinesis in Tyrannosaurus rex. Anat Rec (Hoboken) 2019; 303:999-1017. [PMID: 31260190 DOI: 10.1002/ar.24219] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 04/13/2019] [Accepted: 04/22/2019] [Indexed: 02/02/2023]
Abstract
The extinct nonavian dinosaur Tyrannosaurus rex, considered one of the hardest biting animals ever, is often hypothesized to have exhibited cranial kinesis, or, mobility of cranial joints relative to the braincase. Cranial kinesis in T. rex is a biomechanical paradox in that forcefully biting tetrapods usually possess rigid skulls instead of skulls with movable joints. We tested the biomechanical performance of a tyrannosaur skull using a series of static positions mimicking possible excursions of the palate to evaluate Postural Kinetic Competency in Tyrannosaurus. A functional extant phylogenetic bracket was employed using taxa, which exhibit measurable palatal excursions: Psittacus erithacus (fore-aft movement) and Gekko gecko (mediolateral movement). Static finite element models of Psittacus, Gekko, and Tyrannosaurus were constructed and tested with different palatal postures using anatomically informed material properties, loaded with muscle forces derived from dissection, phylogenetic bracketing, and a sensitivity analysis of muscle architecture and tested in orthal biting simulations using element strain as a proxy for model performance. Extant species models showed lower strains in naturally occurring postures compared to alternatives. We found that fore-aft and neutral models of Tyrannosaurus experienced lower overall strains than mediolaterally shifted models. Protractor muscles dampened palatal strains, while occipital constraints increased strains about palatocranial joints compared to jaw joint constraints. These loading behaviors suggest that even small excursions can strain elements beyond structural failure. Thus, these postural tests of kinesis, along with the robusticity of other cranial features, suggest that the skull of Tyrannosaurus was functionally akinetic. Anat Rec, 303:999-1017, 2020. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Ian N Cost
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri
| | - Kevin M Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri
| | - Kaleb C Sellers
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri
| | | | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Julian L Davis
- Department of Engineering, University of Southern Indiana, Evansville, Indiana
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri
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Jones MEH, Button DJ, Barrett PM, Porro LB. Digital dissection of the head of the rock dove ( Columba livia) using contrast-enhanced computed tomography. ZOOLOGICAL LETTERS 2019; 5:17. [PMID: 31205748 PMCID: PMC6558907 DOI: 10.1186/s40851-019-0129-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
The rock dove (or common pigeon), Columba livia, is an important model organism in biological studies, including research focusing on head muscle anatomy, feeding kinematics, and cranial kinesis. However, no integrated computer-based biomechanical model of the pigeon head has yet been attempted. As an initial step towards achieving this goal, we present the first three-dimensional digital dissection of the pigeon head based on a contrast-enhanced computed tomographic dataset achieved using iodine potassium iodide as a staining agent. Our datasets enable us to visualize the skeletal and muscular anatomy, brain and cranial nerves, and major sense organs of the pigeon, including very small and fragile features, as well as maintaining the three-dimensional topology of anatomical structures. This work updates and supplements earlier anatomical work on this widely used laboratory organism. We resolve several key points of disagreement arising from previous descriptions of pigeon anatomy, including the precise arrangement of the external adductor muscles and their relationship to the posterior adductor. Examination of the eye muscles highlights differences between avian taxa and shows that pigeon eye muscles are more similar to those of a tinamou than they are to those of a house sparrow. Furthermore, we present our three-dimensional data as publicly accessible files for further research and education purposes. Digital dissection permits exceptional visualisation and will be a valuable resource for further investigations into the head anatomy of other bird species, as well as efforts to reconstruct soft tissues in fossil archosaurs.
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Affiliation(s)
- Marc E. H. Jones
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD UK
| | - David J. Button
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD UK
| | - Paul M. Barrett
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD UK
| | - Laura B. Porro
- Department of Cell and Developmental Biology, UCL, University College London, Gower Street, London, WC1E 6BT UK
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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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8
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Lappin AK, Jones ME. Reliable quantification of bite-force performance requires use of appropriate biting substrate and standardization of bite out-lever. J Exp Biol 2014; 217:4303-12. [DOI: 10.1242/jeb.106385] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Bite-force performance is an ecologically important measure of whole-organism performance that shapes dietary breadth and feeding strategies and, in some taxa, determines reproductive success. It also is a metric critical to testing and evaluating biomechanical models. We reviewed nearly one-hundred published studies of a range of taxa that incorporate direct in vivo measurements of bite force. Problematically, methods of data collection and processing vary considerably among studies. In particular, there is little consensus on the appropriate substrate to use on the biting surface of force transducers. In addition, the bite out-lever, defined as the distance from the fulcrum (i.e. jaw joint) to the position along the jawline at which the jaws engage the transducer, is rarely taken into account. We examined the effect of bite substrate and bite out-lever on bite-force estimates in a diverse sample of lizards. Results indicate that both variables have a significant impact on the accuracy of measurements. Maximum bite force is significantly greater using leather as the biting substrate, as compared to a metal substrate. Less forceful bites on metal are likely due to inhibitory feedback from mechanoreceptors that prevent damage to the feeding apparatus. Standardization of bite out-lever affected which trial produced maximum performance for a given individual. Indeed, maximum bite force usually is underestimated without standardization because it is expected to be greatest at the minimum out-lever (i.e. back of jaws), which in studies is rarely targeted with success. We assert that future studies should use a pliable substrate, such as leather, and employ appropriate standardization for bite out-lever.
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Affiliation(s)
| | - Marc E.H. Jones
- University of Adelaide, Australia; University College London, UK; South Australian Museum, Australia
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9
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Curtis N, Jones MEH, Evans SE, O'Higgins P, Fagan MJ. Cranial sutures work collectively to distribute strain throughout the reptile skull. J R Soc Interface 2013; 10:20130442. [PMID: 23804444 PMCID: PMC3730698 DOI: 10.1098/rsif.2013.0442] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The skull is composed of many bones that come together at sutures. These sutures are important sites of growth, and as growth ceases some become fused while others remain patent. Their mechanical behaviour and how they interact with changing form and loadings to ensure balanced craniofacial development is still poorly understood. Early suture fusion often leads to disfiguring syndromes, thus is it imperative that we understand the function of sutures more clearly. By applying advanced engineering modelling techniques, we reveal for the first time that patent sutures generate a more widely distributed, high level of strain throughout the reptile skull. Without patent sutures, large regions of the skull are only subjected to infrequent low-level strains that could weaken the bone and result in abnormal development. Sutures are therefore not only sites of bone growth, but could also be essential for the modulation of strains necessary for normal growth and development in reptiles.
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Affiliation(s)
- Neil Curtis
- Medical and Biological Engineering Research Group, School of Engineering, University of Hull, Hull HU6 7RX, UK.
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10
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Developing a musculoskeletal model of the primate skull: predicting muscle activations, bite force, and joint reaction forces using multibody dynamics analysis and advanced optimisation methods. J Theor Biol 2012; 310:21-30. [PMID: 22721994 DOI: 10.1016/j.jtbi.2012.06.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 06/01/2012] [Accepted: 06/05/2012] [Indexed: 11/22/2022]
Abstract
An accurate, dynamic, functional model of the skull that can be used to predict muscle forces, bite forces, and joint reaction forces would have many uses across a broad range of disciplines. One major issue however with musculoskeletal analyses is that of muscle activation pattern indeterminacy. A very large number of possible muscle force combinations will satisfy a particular functional task. This makes predicting physiological muscle recruitment patterns difficult. Here we describe in detail the process of development of a complex multibody computer model of a primate skull (Macaca fascicularis), that aims to predict muscle recruitment patterns during biting. Using optimisation criteria based on minimisation of muscle stress we predict working to balancing side muscle force ratios, peak bite forces, and joint reaction forces during unilateral biting. Validation of such models is problematic; however we have shown comparable working to balancing muscle activity and TMJ reaction ratios during biting to those observed in vivo and that peak predicted bite forces compare well to published experimental data. To our knowledge the complexity of the musculoskeletal model is greater than any previously reported for a primate. This complexity, when compared to more simple representations provides more nuanced insights into the functioning of masticatory muscles. Thus, we have shown muscle activity to vary throughout individual muscle groups, which enables them to function optimally during specific masticatory tasks. This model will be utilised in future studies into the functioning of the masticatory apparatus.
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Jones MEH, O'higgins P, Fagan MJ, Evans SE, Curtis N. Shearing mechanics and the influence of a flexible symphysis during oral food processing in Sphenodon (Lepidosauria: Rhynchocephalia). Anat Rec (Hoboken) 2012; 295:1075-91. [PMID: 22644955 DOI: 10.1002/ar.22487] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 04/05/2012] [Indexed: 11/07/2022]
Abstract
The New Zealand tuatara, Sphenodon, has a specialized feeding system in which the teeth of the lower jaw close between two upper tooth rows before sliding forward to slice food apart like a draw cut saw. This shearing action is unique amongst living amniotes but has been compared with the chewing power stroke of mammals. We investigated details of the jaw movement using multibody dynamics analysis of an anatomically accurate three-dimensional computer model constructed from computed tomography scans. The model predicts that a flexible symphysis is necessary for changes in the intermandibular angle that permits prooral movement. Models with the greatest symphysial flexibility allow the articulation surface of the articular to follow the quadrate cotyle with the least restriction, and suggest that shearing is accompanied by a long axis rotation of the lower jaws. This promotes precise point loading between the cutting edges of particular teeth, enhancing the effectiveness of the shearing action. Given that Sphenodon is a relatively inactive reptile, we suggest that the link between oral food processing and endothermy has been overstated. Food processing improves feeding efficiency, a consideration of particular importance when food availability is unpredictable. Although this feeding mechanism is today limited to Sphenodon, a survey of fossil rhynchocephalians suggests that it was once more widespread.
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Affiliation(s)
- Marc E H Jones
- Research Department of Cell and Developmental Biology, UCL, University College London, London, UK.
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Curtis N, Jones MEH, Shi J, O'Higgins P, Evans SE, Fagan MJ. Functional relationship between skull form and feeding mechanics in Sphenodon, and implications for diapsid skull development. PLoS One 2011; 6:e29804. [PMID: 22216358 PMCID: PMC3247290 DOI: 10.1371/journal.pone.0029804] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 12/05/2011] [Indexed: 11/19/2022] Open
Abstract
The vertebrate skull evolved to protect the brain and sense organs, but with the appearance of jaws and associated forces there was a remarkable structural diversification. This suggests that the evolution of skull form may be linked to these forces, but an important area of debate is whether bone in the skull is minimised with respect to these forces, or whether skulls are mechanically "over-designed" and constrained by phylogeny and development. Mechanical analysis of diapsid reptile skulls could shed light on this longstanding debate. Compared to those of mammals, the skulls of many extant and extinct diapsids comprise an open framework of fenestrae (window-like openings) separated by bony struts (e.g., lizards, tuatara, dinosaurs and crocodiles), a cranial form thought to be strongly linked to feeding forces. We investigated this link by utilising the powerful engineering approach of multibody dynamics analysis to predict the physiological forces acting on the skull of the diapsid reptile Sphenodon. We then ran a series of structural finite element analyses to assess the correlation between bone strain and skull form. With comprehensive loading we found that the distribution of peak von Mises strains was particularly uniform throughout the skull, although specific regions were dominated by tensile strains while others were dominated by compressive strains. Our analyses suggest that the frame-like skulls of diapsid reptiles are probably optimally formed (mechanically ideal: sufficient strength with the minimal amount of bone) with respect to functional forces; they are efficient in terms of having minimal bone volume, minimal weight, and also minimal energy demands in maintenance.
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Affiliation(s)
- Neil Curtis
- Medical and Biological Engineering Research Group, Department of Engineering, University of Hull, Hull, United Kingdom.
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13
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Abstract
Multibody modelling is underutilised in craniofacial analyses, particularly when compared to other computational methods such as finite element analysis. However, there are many potential applications within this area, where bony movements, muscle forces, joint kinematics and bite forces can all be studied. This paper provides an overview of recent, three-dimensional, multibody modelling studies related to the analysis of skulls. The goal of this paper is not to offer a critical review of past studies, but instead intends to inform the reader of what has been achieved with multibody modelling.
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Affiliation(s)
- Neil Curtis
- Medical and Biological Engineering Research Group, Department of Engineering, University of Hull, Hull, UK.
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