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Cummings KL, Lovich JE, Puffer SR, Greely S, Otahal CD, Gannon J. Injuries and Abnormalities of the Southwestern Pond Turtle (Actinemys pallida) in the Mojave River of California. WEST N AM NATURALIST 2022. [DOI: 10.3398/064.082.0407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Kristy L. Cummings
- U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Dr., Flagstaff, AZ 86001
| | - Jeffrey E. Lovich
- U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Dr., Flagstaff, AZ 86001
| | - Shellie R. Puffer
- U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Dr., Flagstaff, AZ 86001
| | - Sarah Greely
- The Living Desert, 47900 Portola Avenue, Palm Desert, CA 92260
| | - Christopher D. Otahal
- Bureau of Land Management, Barstow Field Office, 2601 Barstow Road, Barstow, CA 92311
| | - James Gannon
- Bureau of Land Management, 1201 Bird Center Drive, Palm Springs, CA 92262
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2
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Patil AY, Hegde C, Savanur G, Kanakmood SM, Contractor AM, Shirashyad VB, Chivate RM, Kotturshettar BB, Mathad SN, Patil MB, Soudagar MEM, Fattah IMR. Biomimicking Nature-Inspired Design Structures-An Experimental and Simulation Approach Using Additive Manufacturing. Biomimetics (Basel) 2022; 7:biomimetics7040186. [PMID: 36412714 PMCID: PMC9680522 DOI: 10.3390/biomimetics7040186] [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: 09/19/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Whether it is a plant- or animal-based bio-inspiration design, it has always been able to address one or more product/component optimisation issues. Today's scientists or engineers look to nature for an optimal, economically viable, long-term solution. Similarly, a proposal is made in this current work to use seven different bio-inspired structures for automotive impact resistance. All seven of these structures are derived from plant and animal species and are intended to be tested for compressive loading to achieve load-bearing capacity. The work may even cater to optimisation techniques to solve the real-time problem using algorithm-based generative shape designs built using CATIA V6 in unit dimension. The samples were optimised with Rhino 7 software and then simulated with ANSYS workbench. To carry out the comparative study, an experimental work of bioprinting in fused deposition modelling (3D printing) was carried out. The goal is to compare the results across all formats and choose the best-performing concept. The results were obtained for compressive load, flexural load, and fatigue load conditions, particularly the number of life cycles, safety factor, damage tolerance, and bi-axiality indicator. When compared to previous research, the results are in good agreement. Because of their multifunctional properties combining soft and high stiffness and lightweight properties of novel materials, novel materials have many potential applications in the medical, aerospace, and automotive sectors.
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Affiliation(s)
- Arun Y. Patil
- School of Mechanical Engineering, KLE Technological University, Hubballi 580031, India
- Correspondence: (A.Y.P.); (I.M.R.F.)
| | - Chandrashekhar Hegde
- School of Mechanical Engineering, KLE Technological University, Hubballi 580031, India
| | - Guruprasad Savanur
- School of Mechanical Engineering, KLE Technological University, Hubballi 580031, India
| | | | | | - Vinay B. Shirashyad
- School of Mechanical Engineering, KLE Technological University, Hubballi 580031, India
| | - Rahul M. Chivate
- School of Mechanical Engineering, KLE Technological University, Hubballi 580031, India
| | | | - Shridhar N. Mathad
- Department of Physics, KLE Institute of Technology, Hubballi 580030, India
| | | | - Manzoore Elahi M. Soudagar
- Department of Mechanical Engineering, School of Technology, Glocal University, Delhi-Yamunotri Marg, Saharanpur 247121, India
- Department of VLSI Microelectronics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai 602105, India
| | - Islam Md Rizwanul Fattah
- Centre for Green Technology (CGT), School of Civil and Environmental Engineering, Faculty of Engineering and IT, University of Technology Sydney, Ultimo, NSW 2007, Australia
- Correspondence: (A.Y.P.); (I.M.R.F.)
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3
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Higham TE, Schmitz L, Niklas KJ. The evolution of mechanical properties of conifer and angiosperm woods. Integr Comp Biol 2022; 62:icac103. [PMID: 35762654 DOI: 10.1093/icb/icac103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The material properties of the cells and tissues of an organism dictate, to a very large degree, the ability of the organism to cope with mechanical stress induced by externally applied forces. It is, therefore, critical to understand how these properties differ across diverse species and how they have evolved. Herein, a large data base (N = 84 species) for the mechanical properties of wood samples measured at biologically natural moisture contents (i.e., "green wood") was analyzed to determine the extent to which these properties are correlated across phylogenetically diverse tree species, to determine if a phylogenetic pattern of trait values exists, and, if so, to assess whether the rate of trait evolution varies across the phylogeny. The phylogenetic comparative analyses presented here confirm previous results that critical material properties are significantly correlated with one another and with wood density. Although the rates of trait evolution of angiosperms and gymnosperms (i.e., conifers) are similar, the material properties of both clades evolved in distinct selective regimes that are phenotypically manifested in lower values across all material properties in gymnosperms. This observation may be related to the structural differences between gymnosperm and angiosperm wood such as the presence of vessels in angiosperms. Explorations of rate heterogeneity indicate high rates of trait evolution in wood density in clades within both conifers and angiosperms (e.g., Pinus and Shorea). Future analyses are warranted using additional data given these preliminary results, especially because there is ample evidence of convergent evolution in the material properties of conifers and angiosperm wood that appear to experience similar ecological conditions.
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Affiliation(s)
- Timothy E Higham
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, 92521, USA
| | - Lars Schmitz
- W.M. Keck Science Department, 925 N. Mills Avenue, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Karl J Niklas
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
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Eigen L, Baum D, Dean MN, Werner D, Wölfer J, Nyakatura JA. Ontogeny of a tessellated surface: Carapace growth of the longhorn cowfish Lactoria cornuta. J Anat 2022; 241:565-580. [PMID: 35638264 PMCID: PMC9358767 DOI: 10.1111/joa.13692] [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: 03/18/2022] [Revised: 05/06/2022] [Accepted: 05/06/2022] [Indexed: 11/28/2022] Open
Abstract
Biological armors derive their mechanical integrity in part from their geometric architectures, often involving tessellations: individual structural elements tiled together to form surface shells. The carapace of boxfish, for example, is composed of mineralized polygonal plates, called scutes, arranged in a complex geometric pattern and nearly completely encasing the body. In contrast to artificial armors, the boxfish exoskeleton grows with the fish; the relationship between the tessellation and the gross structure of the armor is therefore critical to sustained protection throughout growth. To clarify whether or how the boxfish tessellation is maintained or altered with age, we quantify architectural aspects of the tessellated carapace of the longhorn cowfish Lactoria cornuta through ontogeny (across nearly an order of magnitude in standard length) and in a high‐throughput fashion, using high‐resolution microCT data and segmentation algorithms to characterize the hundreds of scutes that cover each individual. We show that carapace growth is canalized with little variability across individuals: rather than continually adding scutes to enlarge the carapace surface, the number of scutes is surprisingly constant, with scutes increasing in volume, thickness, and especially width with age. As cowfish and their scutes grow, scutes become comparatively thinner, with the scutes at the edges (weak points in a boxy architecture) being some of the thickest and most reinforced in younger animals and thinning most slowly across ontogeny. In contrast, smaller scutes with more variable curvature were found in the limited areas of more complex topology (e.g., around fin insertions, mouth, and anus). Measurements of Gaussian and mean curvature illustrate that cowfish are essentially tessellated boxes throughout life: predominantly zero curvature surfaces comprised of mostly flat scutes, and with scutes with sharp bends used sparingly to form box edges. Since growth of a curved, tiled surface with a fixed number of tiles would require tile restructuring to accommodate the surface's changing radius of curvature, our results therefore illustrate a previously unappreciated advantage of the odd boxfish morphology: by having predominantly flat surfaces, it is the box‐like body form that in fact permits a relatively straightforward growth system of this tessellated architecture (i.e., where material is added to scute edges). Our characterization of the ontogeny and maintenance of the carapace tessellation provides insights into the potentially conflicting mechanical, geometric, and developmental constraints of this species but also perspectives into natural strategies for constructing mutable tiled architectures. The carapace of boxfish is composed of mineralized polygonal plates, called scutes, arranged in a complex geometric pattern and nearly completely encasing the body. To clarify whether or how this armor is maintained or altered with age, we quantify architectural aspects of the carapace of the longhorn cowfish Lactoria cornuta through ontogeny, using high‐resolution microCT data and segmentation algorithms to characterize the hundreds of scutes that cover each individual.![]()
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Affiliation(s)
- Lennart Eigen
- Comparative Zoology, Institute of Biology, Humboldt University of Berlin, Berlin, Germany.,Bernstein Center for Computational Neuroscience Berlin, Humboldt University of Berlin, Berlin, Germany
| | - Daniel Baum
- Visual and Data-Centric Computing Department, Zuse Institute Berlin, Berlin, Germany
| | - Mason N Dean
- Comparative Zoology, Institute of Biology, Humboldt University of Berlin, Berlin, Germany.,Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Daniel Werner
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Jan Wölfer
- Comparative Zoology, Institute of Biology, Humboldt University of Berlin, Berlin, Germany
| | - John A Nyakatura
- Comparative Zoology, Institute of Biology, Humboldt University of Berlin, Berlin, Germany
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5
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Lazarus BS, Chadha C, Velasco-Hogan A, Barbosa JD, Jasiuk I, Meyers MA. Engineering with keratin: A functional material and a source of bioinspiration. iScience 2021; 24:102798. [PMID: 34355149 PMCID: PMC8319812 DOI: 10.1016/j.isci.2021.102798] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Keratin is a highly multifunctional biopolymer serving various roles in nature due to its diverse material properties, wide spectrum of structural designs, and impressive performance. Keratin-based materials are mechanically robust, thermally insulating, lightweight, capable of undergoing reversible adhesion through van der Waals forces, and exhibit structural coloration and hydrophobic surfaces. Thus, they have become templates for bioinspired designs and have even been applied as a functional material for biomedical applications and environmentally sustainable fiber-reinforced composites. This review aims to highlight keratin's remarkable capabilities as a biological component, a source of design inspiration, and an engineering material. We conclude with future directions for the exploration of keratinous materials.
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Affiliation(s)
- Benjamin S. Lazarus
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | - Charul Chadha
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - Audrey Velasco-Hogan
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | | | - Iwona Jasiuk
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - Marc A. Meyers
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA
- Department of Mechanical and Aerospace Engineering, University of California San Diego, San Diego, CA, USA
- Department of Nanoengineering, University of California San Diego, San Diego, CA, USA
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6
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Dziomber L, Joyce WG, Foth C. The ecomorphology of the shell of extant turtles and its applications for fossil turtles. PeerJ 2020; 8:e10490. [PMID: 33391873 PMCID: PMC7761203 DOI: 10.7717/peerj.10490] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 11/13/2020] [Indexed: 11/20/2022] Open
Abstract
Turtles are a successful clade of reptiles that originated in the Late Triassic. The group adapted during its evolution to different types of environments, ranging from dry land to ponds, rivers, and the open ocean, and survived all Mesozoic and Cenozoic extinction events. The body of turtles is characterized by a shell, which has been hypothesized to have several biological roles, like protection, thermal and pH regulation, but also to be adapted in its shape to the ecology of the animal. However, only few studies have investigated the relationships between shell shape and ecology in a global context or clarified if shape can be used to diagnose habitat preferences in fossil representatives. Here, we assembled a three-dimensional dataset of 69 extant turtles and three fossils, in particular, the Late Triassic Proganochelys quenstedtii and Proterochersis robusta and the Late Jurassic Plesiochelys bigleri to test explicitly for a relationship between shell shape and ecology. 3D models were obtained using surface scanning and photogrammetry. The general shape of the shells was captured using geometric morphometrics. The habitat ecology of extant turtles was classified using the webbing of their forelimbs as a proxy. Principal component analysis (PCA) highlights much overlap between habitat groups. Discriminant analyses suggests significant differences between extant terrestrial turtles, extant fully aquatic (i.e., marine and riverine) turtles, and an unspecialized assemblage that includes extant turtles from all habitats, mostly freshwater aquatic forms. The paleoecology of the three fossil species cannot be determined with confidence, as all three fall within the unspecialized category, even if Plesiochelys bigleri plots closer to fully aquatic turtles, while the two Triassic species group closer to extant terrestrial forms. Although the shape of the shell of turtles indeed contains an ecological signal, it is overall too weak to uncover using shell shape in paleoecological studies, at least with the methods we selected.
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Affiliation(s)
- Laura Dziomber
- Department of Geosciences, University of Fribourg, Fribourg, Switzerland
- Institute of Plant Sciences & Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Walter G. Joyce
- Department of Geosciences, University of Fribourg, Fribourg, Switzerland
| | - Christian Foth
- Department of Geosciences, University of Fribourg, Fribourg, Switzerland
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7
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Silva ICCD, Bonelli MDA, Rameh-de-Albuquerque LC, Zanotti AP, Siqueira DBD, Fernandes THT, Costa FS. Computed tomography of the lungs of healthy captive red-footed tortoises (Chelonoidis carbonaria). J Exot Pet Med 2020. [DOI: 10.1053/j.jepm.2020.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Ampaw E, Owoseni TA, Du F, Pinilla N, Obayemi J, Hu J, Nigay PM, Nzihou A, Uzonwanne V, Zebaze-Kana MG, Dewoolkar M, Tan T, Soboyejo W. Compressive deformation and failure of trabecular structures in a turtle shell. Acta Biomater 2019; 97:535-543. [PMID: 31310853 DOI: 10.1016/j.actbio.2019.07.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/22/2022]
Abstract
Turtle shells comprising of cortical and trabecular bones exhibit intriguing mechanical properties. In this work, compression tests were performed using specimens made from the carapace of Kinixys erosa turtle. A combination of imaging techniques and mechanical testing were employed to examine the responses of hierarchical microstructures of turtle shell under compression. Finite element models produced from microCT-scanned microstructures and analytical foam structure models were then used to elucidate local responses of trabecular bones deformed under compression. The results reveal the contributions from micro-strut bending and stress concentrations to the fractural mechanisms of trabecular bone structures. The porous structures of turtle shells could be an excellent prototype for the bioinspired design of deformation-resistant structures. STATEMENT OF SIGNIFICANCE: In this study, a combination of analytical, computational models and experiments is used to study the underlying mechanisms that contribute to the compressive deformation of a Kinixys erosa turtle shell between the nano-, micro- and macro-scales. The proposed work shows that the turtle shell structures can be analyzed as sandwich structures that have the capacity to concentrate deformation and stresses within the trabecular bones, which enables significant energy absorption during compressive deformation. Then, the trends in the deformation characteristics and the strengths of the trabecular bone segments are well predicted by the four-strut model, which captures the effects of variations in strut length, thickness and orientation that are related to microstructural uncertainties of the turtle shells. The above results also suggest that the model may be used to guide the bioinspired design of sandwich porous structures that mimic the properties of the cortical and trabecular bone segments of turtle shells under a range of loading conditions.
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Affiliation(s)
- Edward Ampaw
- Department of Materials Science and Engineering, African University of Science and Technology, Nigeria; Department of Mechanical Engineering, Koforidua Technical University, Koforidua, Ghana
| | - Tunji Adetayo Owoseni
- Department of Materials Science and Engineering, African University of Science and Technology, Nigeria
| | - Fen Du
- Department of Mechanical Engineering, Vermont Technical College, Randolph Center, VT 05061, USA
| | - Nelson Pinilla
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08540, USA
| | - John Obayemi
- Department of Mechanical Engineering, Worcester Polytechnic Institute, MA 01609, USA
| | - Jingjie Hu
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08540, USA
| | - Pierre-Marie Nigay
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08540, USA; Department of Mechanical Engineering, Worcester Polytechnic Institute, MA 01609, USA
| | - Ange Nzihou
- Department of Chemical Engineering, Université de Toulouse, Mines Albi, CNRS UMR 5302, Centre RAPSODEE, F-81013 Albi Cedex 09, France
| | - Vanessa Uzonwanne
- Department of Mechanical Engineering, Worcester Polytechnic Institute, MA 01609, USA
| | | | - Mandar Dewoolkar
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT 05405, USA
| | - Ting Tan
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT 05405, USA
| | - Winston Soboyejo
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08540, USA; Department of Mechanical Engineering, Worcester Polytechnic Institute, MA 01609, USA.
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9
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Williams C, Stayton CT. Effects of Sutured Pelvic Elements on Turtle Shell Strength: A Comparison of Pleurodire and Cryptodire Shell Mechanics. HERPETOLOGICA 2019. [DOI: 10.1655/d-17-00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Cameron Williams
- Department of Biology, Bucknell University, Lewisburg, PA 17837, USA
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10
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Heterogeneous bioapatite carbonation in western painted turtles is unchanged after anoxia. Comp Biochem Physiol A Mol Integr Physiol 2019; 233:74-83. [PMID: 30930203 DOI: 10.1016/j.cbpa.2019.03.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/09/2019] [Accepted: 03/25/2019] [Indexed: 11/23/2022]
Abstract
Adsorbed and structurally incorporated carbonate in bioapatite, the primary mineral phase of bone, is observed across vertebrates, typically at 2-8 wt%, and supports critical physiological and biochemical functions. Several turtle species contain elevated bone-associated carbonate, a property linked to pH buffering and overwintering survival. Prior studies of turtle bone utilized bulk analyses, which do not provide spatial resolution of carbonate. Using Raman spectroscopy, the goals of this study were to: (1) quantify and spatially resolve carbonate heterogeneity within the turtle shell; (2) determine if cortical and trabecular bone contain distinct carbonate concentrations; and (3) assess if simulated overwintering conditions result in decreased bioapatite carbonation. Here, we demonstrate the potential for Raman spectroscopic analysis to spatially resolve bioapatite carbonation, using the western painted turtle as a model species. Carbonate concentration was highly variable within cortical and trabecular bone, based on calibrated Raman spot analyses and mapping, suggesting heterogeneous carbonate distribution among crystallites. Mean carbonate concentration did not significantly differ between cortical and trabecular bone, which indicates random distribution of crystallites with elevated and depleted carbonate. Carbonate concentrations (range: 5-22 wt%) were not significantly different in overwintering and control animals, deviating from previous bulk analyses. In reconciling bulk and Raman analyses, two hypotheses explain how overwintering turtles potentially access carbonate: (1) mobilization of mineral-associated, surface components of bone crystallites; and (2) selective, dispersed crystallite dissolution. Elevated bioapatite carbonate in the western painted turtle, averaging 11.8 wt%, represents the highest carbonation observed in vertebrates, and is one physiological trait that facilitates overwintering survival.
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11
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Stayton CT. Warped finite element models predict whole shell failure in turtle shells. J Anat 2018; 233:666-678. [PMID: 30058131 PMCID: PMC6182993 DOI: 10.1111/joa.12871] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2018] [Indexed: 01/08/2023] Open
Abstract
Finite element (FE) models have become increasingly popular in comparative biomechanical studies, with researchers continually developing methods such as 'warping' preexisting models to facilitate analyses. However, few studies have investigated how well FE models can predict biologically crucial whole-structure performance or whether 'warped' models can provide useful information about the mechanical behavior of actual specimens. This study addresses both of these issues through a validation of warped FE models of turtle shells. FE models for 40 turtle specimens were built using 3D landmark coordinates and thin-plate spline interpolations to warp preexisting turtle shell models. Each actual turtle specimen was loaded to failure, and the load at failure and mode of fracture were then compared with the behavior predicted by the models. Overall, the models performed very well, despite the fact that many simplifying assumptions were made for analysis. Regressions of observed on predicted loads were significant for the dataset as a whole, as well as in separate analyses within two turtle species, and the direction of fracture was generally consistent with the patterns of stresses observed in the models. This was true even when size (an important factor in determining strength) was removed from analyses - the models were also able to predict which shells would be relatively stronger or weaker. Although some residual variation remains unexplained, this study supports the idea that warped FE models run with simplifying assumptions at least can provide useful information for comparative biomechanical studies.
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12
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Stevens LM, Blob RW, Mayerl CJ. Ontogeny, morphology and performance: changes in swimming stability and turning performance in the freshwater pleurodire turtle, Emydura subglobosa. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Lucy M Stevens
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | - Richard W Blob
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
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13
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Salmon M, Coppenrath C, Higgins B. The early ontogeny of carapace armoring in hawksbill sea turtles (Eretmochelys imbricata), with comparisons to its close relatives (Loggerhead, Caretta caretta; Kemp's ridley, Lepidochelys kempii). J Morphol 2018; 279:1224-1233. [PMID: 30105840 DOI: 10.1002/jmor.20844] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 11/11/2022]
Abstract
In this study, we compare and contrast armoring strategies during early ontogeny among three related species of marine turtles: the hawksbill, a species that diverged about 29 mya from the loggerhead and Kemp's ridley, which diverged from one another about 16 mya. Our purpose was to determine whether there was a correlation between divergence time and the evolution of unique morphological armoring specializations among these species. To find out, we completed a more detailed analysis of shell morphology for all of the species that revealed the following patterns. First, each species has evolved a somewhat different armoring strategy, suggesting that shell morphological evolution is surprisingly flexible. Second, hawksbills possess armoring features that are unique among all marine turtle species, suggesting a correlation between divergence through time and divergence in morphology. However, hawksbills also frequent coral reefs and selection pressures promoting their survival in those habitats may also have shaped their unique morphology. In contrast, loggerhead and Kemp's ridley turtles share similar armoring features that differ primarily in when during ontogeny they appear and in their degree of expression. Third, the armoring adaptations shown generally by juvenile marine turtles resemble those found among marine fishes of comparable size, probably because both small turtles and fishes are exposed to similar predators that promote evolutionarily similar adaptations.
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Affiliation(s)
- Michael Salmon
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, 33431
| | - Christina Coppenrath
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, 33431
| | - Benjamin Higgins
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center, Galveston, Texas
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14
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Broeckhoven C, Mouton PLLFN, Hui C. Proximate causes of variation in dermal armour: insights from armadillo lizards. OIKOS 2018. [DOI: 10.1111/oik.05401] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Chris Broeckhoven
- Laboratory of Functional Morphology, Dept of Biology; Univ. of Antwerp; Universiteitsplein 1 BE-2610 Wilrijk Belgium
- Dept of Mathematical Sciences; Stellenbosch Univ.; Stellenbosch South Africa
| | | | - Cang Hui
- Dept of Mathematical Sciences; Stellenbosch Univ.; Stellenbosch South Africa
- Theoretical and Physical Biosciences; African Inst. for Mathematical Sciences; Cape Town South Africa
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15
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White ZW, Vernerey FJ. Armours for soft bodies: how far can bioinspiration take us? BIOINSPIRATION & BIOMIMETICS 2018; 13:041004. [PMID: 29595522 DOI: 10.1088/1748-3190/aababa] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The development of armour is as old as the dawn of civilization. Early man looked to natural structures to harvest or replicate for protection, leaning on millennia of evolutionary developments in natural protection. Since the advent of more modern weaponry, Armor development has seemingly been driven more by materials research than bio-inspiration. However, parallels can still be drawn between modern bullet-protective armours and natural defensive structures. Soft armour for handgun and fragmentation threats can be likened to mammalian skin, and similarly, hard armour can be compared with exoskeletons and turtle shells. Via bio-inspiration, it may be possible to develop structures previously un-researched for ballistic protection. This review will cover current modern ballistic protective structures focusing on energy dissipation and absorption methods, and their natural analogues. As all armour is a compromise between weight, flexibility and protection, the imbricated structure of scaled skin will be presented as a better balance between these factors.
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Affiliation(s)
- Zachary W White
- Mechanical Engineering, University of Colorado Boulder, 427 UCB, Boulder, United States of America
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Abnormal Shell Shapes in Northern Map Turtles of the Juniata River, Pennsylvania, USA. J HERPETOL 2018. [DOI: 10.1670/17-030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Odegard DT, Sonnenfelt MA, Bledsoe JG, Keenan SW, Hill CA, Warren DE. Changes in the material properties of the shell during simulated aquatic hibernation in the anoxia-tolerant painted turtle. J Exp Biol 2018; 221:jeb.176990. [DOI: 10.1242/jeb.176990] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 07/25/2018] [Indexed: 11/20/2022]
Abstract
Western painted turtles (Chrysemys picta bellii) tolerate anoxic submergence longer than any other tetrapod, surviving more than 170 days at 3°C. This ability is due, in part, to the shell and skeleton simultaneously releasing calcium and magnesium carbonates, and sequestering lactate and H+ to prevent lethal decreases in body fluid pH. We evaluated the effects of anoxic submergence at 3°C on various material properties of painted turtle bone after 60, 130, and 167-170 days, and compared them to normoxic turtles held at the same temperature for the same time periods. To assess changes in the mechanical properties, beams (4×25 mm) were milled from the plastron and broken in a three-point flexural test. Bone mineral density, CO2 concentration (a measure of total bone HCO3−/CO32-), and elemental composition were measured using microCT, HCO3−/CO32- titration, and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Tissue mineral density of the sampled bone beams were not significantly altered by 167-170 days of aquatic overwintering in anoxic or normoxic water, but bone CO2 and Mg were depleted in anoxic compared normoxic turtles. At this time point, the plastron beams from anoxic turtles yielded at stresses that were significantly smaller and strains significantly greater than the plastron beams of normoxic turtles. When data from anoxic and normoxic turtles were pooled, plastron beams had a diminished elastic modulus after 167-170 days compared to control turtles sampled on Day 1, indicating an effect of prolonged housing of the turtles in 3°C water without access to basking sites. There were no changes in the mechanical properties of the plastron beams at any of the earlier time points in either group. We conclude that anoxic hibernation can weaken the painted turtle's plastron, but likely only after durations that exceed what it might naturally experience. The duration of aquatic overwintering, regardless of oxygenation state, is likely to be an important factor determining the mechanical properties of the turtle shell during spring emergence.
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Affiliation(s)
- Dean T. Odegard
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Michael A. Sonnenfelt
- Department of Biomedical Engineering, Saint Louis University, St. Louis, MO 63103, USA
| | - J. Gary Bledsoe
- Department of Biomedical Engineering, Saint Louis University, St. Louis, MO 63103, USA
| | - Sarah W. Keenan
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Craig A. Hill
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Daniel E. Warren
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
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Scheyer TM, Delfino M, Klein N, Bunbury N, Fleischer-Dogley F, Hansen DM. Trophic interactions between larger crocodylians and giant tortoises on Aldabra Atoll, Western Indian Ocean, during the Late Pleistocene. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171800. [PMID: 29410873 PMCID: PMC5792950 DOI: 10.1098/rsos.171800] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/06/2017] [Indexed: 06/08/2023]
Abstract
Today, the UNESCO World Heritage Site of Aldabra Atoll is home to about 100 000 giant tortoises, Aldabrachelys gigantea, whose fossil record goes back to the Late Pleistocene. New Late Pleistocene fossils (age ca. 90-125 000 years) from the atoll revealed some appendicular bones and numerous shell fragments of giant tortoises and cranial and postcranial elements of crocodylians. Several tortoise bones show circular holes, pits and scratch marks that are interpreted as bite marks of crocodylians. The presence of a Late Pleistocene crocodylian species, Aldabrachampsus dilophus, has been known for some time, but the recently found crocodylian remains presented herein are distinctly larger than those previously described. This indicates the presence of at least some larger crocodylians, either of the same or of a different species, on the atoll. These larger crocodylians, likely the apex predators in the Aldabra ecosystem at the time, were well capable of inflicting damage on even very large giant tortoises. We thus propose an extinct predator-prey interaction between crocodylians and giant tortoises during the Late Pleistocene, when both groups were living sympatrically on Aldabra, and we discuss scenarios for the crocodylians directly attacking the tortoises or scavenging on recently deceased animals.
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Affiliation(s)
- Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Via Valperga Caluso 35, I-10125 Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Carrer de les Columnes s/n, Campus de la UAB, Cerdanyola del Vallès, Barcelona 08193, Spain
| | - Nicole Klein
- Steinmann Institut für Geologie, Paläontologie und Mineralogie, Universität Bonn, Nussallee 8, 53115 Bonn, Germany
| | - Nancy Bunbury
- Seychelles Islands Foundation, PO Box 853, Victoria, Mahé, Seychelles
| | | | - Dennis M. Hansen
- Zoological Museum and the Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Surface protection in bio-shields via a functional soft skin layer: Lessons from the turtle shell. J Mech Behav Biomed Mater 2017; 73:68-75. [DOI: 10.1016/j.jmbbm.2017.01.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 01/05/2023]
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20
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Achrai B, Wagner HD. The turtle carapace as an optimized multi-scale biological composite armor – A review. J Mech Behav Biomed Mater 2017; 73:50-67. [DOI: 10.1016/j.jmbbm.2017.02.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 02/19/2017] [Accepted: 02/24/2017] [Indexed: 01/03/2023]
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21
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Mechanical properties and numerical simulation of Sulcata tortoise carapace. J Mech Behav Biomed Mater 2017; 72:261-267. [DOI: 10.1016/j.jmbbm.2017.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/08/2017] [Accepted: 04/10/2017] [Indexed: 11/20/2022]
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22
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Habegger ML, Huber DH, Lajeunesse MJ, Motta PJ. Theoretical calculations of bite force in billfishes. J Zool (1987) 2017. [DOI: 10.1111/jzo.12465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. L. Habegger
- Department of Biology Florida Southern College Lakeland FL USA
- Department of Integrative Biology University of South Florida Tampa FL USA
- Fish and Wildlife Research Institute Florida Fish and Wildlife Conservation Commission St. Petersburg FL USA
| | - D. H. Huber
- Department of Biology The University of Tampa Tampa FL USA
| | - M. J. Lajeunesse
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - P. J. Motta
- Department of Integrative Biology University of South Florida Tampa FL USA
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23
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Berlant ZS, Stayton TC. Shell Morphology in the Kinosternidae: Functional and Evolutionary Patterns. HERPETOLOGICA 2017. [DOI: 10.1655/herpetologica-d-15-00064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Affiliation(s)
- Michael Dosik
- Department of Biology, Bucknell University, Lewisburg, PA 17837, USA
| | - Tristan Stayton
- Department of Biology, Bucknell University, Lewisburg, PA 17837, USA
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25
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Chen IH, Yang W, Meyers MA. Leatherback sea turtle shell: A tough and flexible biological design. Acta Biomater 2015; 28:2-12. [PMID: 26391496 DOI: 10.1016/j.actbio.2015.09.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/19/2015] [Accepted: 09/17/2015] [Indexed: 11/17/2022]
Abstract
The leatherback sea turtle is unique among chelonians for having a soft skin which covers its osteoderms. The osteoderm is composed of bony plates that are interconnected with collagen fibers in a structure called suture. The soft dermis and suture geometry enable a significant amount of flexing of the junction between adjacent osteoderms. This design allows the body to contract better than a hard-shelled sea turtle as it dives to depths of over 1,000 m. The leatherback turtle has ridges along the carapace to enhance the hydrodynamic flow and provide a tailored stiffness. The osteoderms are of two types: flat and ridged. The structure of the two types of osteoderms is characterized and their mechanical properties are investigated with particular attention to the failure mechanisms. They both are bony structures with a porous core sandwiched between compact layers that form the outside and inside surfaces. The compressive strength is highly anisotropic by virtue of the interaction between loading orientation and arrangement of porous and compact components of osteoderms. The angle of interpenetration at the suture of osteoderms is analyzed and compared with analytical predictions. The sutures have a triangular shape with an angle of ∼30° which provides a balance between the tensile strength of the osteoderms and shear strength of the collagen fiber layer and is verified by Li-Ortiz-Boyce in a previous study. This is confirmed by an FEM analysis. A calculation is developed to quantify the flexibility of the carapace and plastron as a function of the angular displacement at the sutures, predicting the interdependence between geometrical parameters and flexibility. STATEMENT OF SIGNIFICANCE The leatherback turtle is a magnificent chelonian whose decreasing numbers have brought it to the brink of extinction in the Pacific Ocean. This first study of the structure of its shell provides important new insights that explain its amazing capacity for diving: depths of over 1,000 m have been recorded. This is enabled by the flexibility between the bony plates comprising its shell, which is covered by a skin and not by hard keratin as all other turtles. We use the arsenal of Materials Science characterization techniques to probe the structure of the shell and explain its amazing structure and capacity for flexing, while retaining its protection capability.
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Affiliation(s)
- Irene H Chen
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wen Yang
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Marc A Meyers
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA; Departments of Nanoengineering and Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
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26
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Achrai B, Daniel Wagner H. The red-eared slider turtle carapace under fatigue loading: The effect of rib–suture arrangement. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 53:128-33. [DOI: 10.1016/j.msec.2015.04.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/26/2015] [Accepted: 04/21/2015] [Indexed: 11/30/2022]
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27
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Habegger ML, Dean MN, Dunlop JWC, Mullins G, Stokes M, Huber DR, Winters D, Motta PJ. Feeding in billfishes: inferring the role of the rostrum from a biomechanical standpoint. J Exp Biol 2015; 218:824-36. [DOI: 10.1242/jeb.106146] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Perhaps the most striking feature of billfishes is the extreme elongation of the premaxillary bones forming their rostra. Surprisingly, the exact role of this structure in feeding is still controversial. The goal of this study is to investigate the use of the rostrum from a functional, biomechanical and morphological standpoint to ultimately infer its possible role during feeding. Using beam theory, experimental and theoretical loading tests were performed on the rostra from two morphologically different billfish, the blue marlin (Makaira nigricans) and the swordfish (Xiphias gladius). Two loading regimes were applied (dorsoventral and lateral) to simulate possible striking behaviors. Histological samples and material properties of the rostra were obtained along their lengths to further characterize structure and mechanical performance. Intraspecific results show similar stress distributions for most regions of the rostra, suggesting that this structure may be designed to withstand continuous loadings with no particular region of stress concentration. Although material stiffness increased distally, flexural stiffness increased proximally owing to higher second moment of area. The blue marlin rostrum was stiffer and resisted considerably higher loads for both loading planes compared with that of the swordfish. However, when a continuous load along the rostrum was considered, simulating the rostrum swinging through the water, swordfish exhibited lower stress and drag during lateral loading. Our combined results suggest that the swordfish rostrum is suited for lateral swiping to incapacitate their prey, whereas the blue marlin rostrum is better suited to strike prey from a wider variety of directions.
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Affiliation(s)
- Maria L. Habegger
- Department of Integrative Biology, University of South Florida, 4202 E. Fowler Ave, Tampa, FL 33613, USA
| | - Mason N. Dean
- Department of Biomaterials, Max Planck Institute of Colloids & Interfaces, Am Muehlenberg 1, Potsdam 14476, Germany
| | - John W. C. Dunlop
- Department of Biomaterials, Max Planck Institute of Colloids & Interfaces, Am Muehlenberg 1, Potsdam 14476, Germany
| | - Gray Mullins
- Department of Civil and Environmental Engineering, University of South Florida, 4202 E. Fowler Ave, Tampa, FL 33613, USA
| | - Michael Stokes
- Department of Civil and Environmental Engineering, University of South Florida, 4202 E. Fowler Ave, Tampa, FL 33613, USA
| | - Daniel R. Huber
- Department of Biology, University of Tampa, 401 W. Kennedy Blvd, Tampa, FL 33606, USA
| | - Daniel Winters
- Department of Civil and Environmental Engineering, University of South Florida, 4202 E. Fowler Ave, Tampa, FL 33613, USA
| | - Philip J. Motta
- Department of Integrative Biology, University of South Florida, 4202 E. Fowler Ave, Tampa, FL 33613, USA
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28
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Achrai B, Bar-On B, Wagner HD. Biological armors under impact--effect of keratin coating, and synthetic bio-inspired analogues. BIOINSPIRATION & BIOMIMETICS 2015; 10:016009. [PMID: 25599251 DOI: 10.1088/1748-3190/10/1/016009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A number of biological armors, such as turtle shells, consist of a strong exoskeleton covered with a thin keratin coating. The mechanical role upon impact of this keratin coating has surprisingly not been investigated thus far. Low-velocity impact tests on the turtle shell reveal a unique toughening phenomenon attributed to the thin covering keratin layer, the presence of which noticeably improves the fracture energy and shell integrity. Synthetic substrate/coating analogues were subsequently prepared and exhibit an impact behavior similar to the biological ones. The results of the present study may improve our understanding, and even future designs, of impact-tolerant structures.
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Affiliation(s)
- B Achrai
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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29
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Scheyer TM, Danilov IG, Sukhanov VB, Syromyatnikova EV. The shell bone histology of fossil and extant marine turtles revisited. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12265] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Torsten M. Scheyer
- Paläontologisches Institut und Museum; Universität Zürich; Karl Schmid-Strasse 4 CH-8006 Zürich Switzerland
| | - Igor G. Danilov
- Zoological Institute of the Russian Academy of Sciences; Universitetskaya Emb., 1 St. Petersburg 199034 Russia
| | - Vladimir B. Sukhanov
- Paleontological Institute of the Russian Academy of Sciences; Profsoyuznaya Str. 123 Moscow 117997 Russia
| | - Elena V. Syromyatnikova
- Zoological Institute of the Russian Academy of Sciences; Universitetskaya Emb., 1 St. Petersburg 199034 Russia
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30
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Allometric growth in juvenile marine turtles: possible role as an antipredator adaptation. ZOOLOGY 2014; 117:131-8. [PMID: 24629459 DOI: 10.1016/j.zool.2013.11.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 11/04/2013] [Accepted: 11/14/2013] [Indexed: 11/24/2022]
Abstract
Female marine turtles produce hundreds of offspring during their lifetime but few survive because small turtles have limited defenses and are vulnerable to many predators. Little is known about how small turtles improve their survival probabilities with growth though it is assumed that they do. We reared green turtles (Chelonia mydas) and loggerheads (Caretta caretta) from hatchlings to 13 weeks of age and documented that they grew wider faster than they grew longer. This pattern of allometric growth might enable small turtles to more quickly achieve protection from gape-limited predators, such as the dolphinfish (Coryphaena hippurus). As a test of that hypothesis, we measured how dolphinfish gape increased with length, reviewed the literature to determine how dolphinfish populations were size/age structured in nearby waters, and then determined the probability that a small turtle would encounter a fish large enough to consume it if it grew by allometry vs. by isometry (in which case it retained its hatchling proportions). Allometric growth more quickly reduced the probability of a lethal encounter than did isometric growth. On that basis, we suggest that allometry during early ontogeny may have evolved because it provides a survival benefit for small turtles.
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31
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Achrai B, Bar-On B, Wagner HD. Bending mechanics of the red-eared slider turtle carapace. J Mech Behav Biomed Mater 2014; 30:223-33. [DOI: 10.1016/j.jmbbm.2013.09.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/26/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
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