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Tingle JL, Garner KL, Astley HC. Functional diversity of snake locomotor behaviors: A review of the biological literature for bioinspiration. Ann N Y Acad Sci 2024; 1533:16-37. [PMID: 38367220 DOI: 10.1111/nyas.15109] [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] [Indexed: 02/19/2024]
Abstract
Organismal solutions to natural challenges can spark creative engineering applications. However, most engineers are not experts in organismal biology, creating a potential barrier to maximally effective bioinspired design. In this review, we aim to reduce that barrier with respect to a group of organisms that hold particular promise for a variety of applications: snakes. Representing >10% of tetrapod vertebrates, snakes inhabit nearly every imaginable terrestrial environment, moving with ease under many conditions that would thwart other animals. To do so, they employ over a dozen different types of locomotion (perhaps well over). Lacking limbs, they have evolved axial musculoskeletal features that enable their vast functional diversity, which can vary across species. Different species also have various skin features that provide numerous functional benefits, including frictional anisotropy or isotropy (as their locomotor habits demand), waterproofing, dirt shedding, antimicrobial properties, structural colors, and wear resistance. Snakes clearly have much to offer to the fields of robotics and materials science. We aim for this review to increase knowledge of snake functional diversity by facilitating access to the relevant literature.
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Affiliation(s)
| | - Kelsey L Garner
- Department of Biology, University of Akron, Akron, Ohio, USA
| | - Henry C Astley
- Department of Biology, University of Akron, Akron, Ohio, USA
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Adriaens D, Herrel A. Is vertebral shape variability in caecilians (Amphibia: Gymnophiona) constrained by forces experienced during burrowing? J Exp Biol 2022; 225:275610. [PMID: 35662342 DOI: 10.1242/jeb.244288] [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: 03/17/2022] [Accepted: 05/18/2022] [Indexed: 11/20/2022]
Abstract
Caecilians are predominantly burrowing, elongate, limbless amphibians that remain relatively poorly studied. Although it has been suggested that the sturdy and compact skulls of caecilians are an adaptation to their head-first burrowing habits, no clear relationship between skull shape and burrowing performance appears to exist. However, the external forces encountered during burrowing are transmitted by the skull to the vertebral column, and as such, may impact vertebral shape. Additionally, the muscles that generate the burrowing forces attach onto the vertebral column and consequently may impact vertebral shape that way as well. Here, we explore the relationships between vertebral shape and maximal in vivo push forces in 13 species of caecilian amphibians. Our results show that the shape of the two most anterior vertebrae, as well as the shape of the vertebrae at 90% of the total body length, are not correlated with peak push forces. Conversely, the shape of the third vertebrae, and the vertebrae at 20% and 60% of the total body length, do show a relationship to push forces measured in vivo. Whether these relationships are indirect (external forces constraining shape variation) or direct (muscles forces constraining shape variation) remains unclear and will require quantitative studies of the axial musculature. Importantly, our data suggest that mid-body vertebrae may potentially be used as proxies to infer burrowing capacity in fossil representatives.
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Affiliation(s)
- Aurélien Lowie
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Barbara De Kegel
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Mark Wilkinson
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - John Measey
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Private Bag X1, 7602 Matieland, Stellenbosch, South Africa
| | - James C O'Reilly
- Department of Biomedical Sciences, Ohio University, Cleveland Campus, SPS-334C, Cleveland, OH 45701, USA
| | - Nathan J Kley
- Department of Anatomical Sciences, Health Sciences Center, T8-082, Stony Brook University, Stony Brook, NY 11794-8081, USA
| | - Philippe Gaucher
- USR 3456, CNRS, Centre de recherche de Montabo IRD, CNRS-Guyane, 97334 Cayenne, French Guiana
| | - Jonathan Brecko
- Royal Museum for Central Africa, Biological Collections and Data Management, 3080 Tervuren, Belgium
| | | | - Dominique Adriaens
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Anthony Herrel
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.,UMR 7179 C.N.R.S/M.N.H.N., Département d'Ecologie et de Gestion de la Biodiversité, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France
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Lowie A, De Kegel B, Wilkinson M, Measey J, O'Reilly JC, Kley NJ, Gaucher P, Brecko J, Kleinteich T, Adriaens D, Herrel A. The relationship between head shape, head musculature and bite force in caecilians (Amphibia: Gymnophiona). J Exp Biol 2021; 225:273674. [PMID: 34897477 DOI: 10.1242/jeb.243599] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/06/2021] [Indexed: 11/20/2022]
Abstract
Caecilians are enigmatic limbless amphibians that, with a few exceptions all have an at least partly burrowing lifestyle. Although it has been suggested that caecilian evolution resulted in sturdy and compact skulls as an adaptation to their head-first burrowing habits, no relationship between skull shape and burrowing performance has been demonstrated to date. However, the unique dual jaw-closing mechanism and the osteological variability of their temporal region suggest a potential relationship between skull shape and feeding mechanics. Here, we explored the relationships between skull shape, head musculature, and in vivo bite forces. Although there is a correlation between bite force and external head shape, no relationship between bite force and skull shape could be detected. Whereas our data suggest that muscles are the principal drivers of variation in bite force, the shape of the skull is constrained by factors other than demands for bite force generation. However, a strong covariation between the cranium and mandible exists. Moreover, both cranium and mandible shape covary with jaw muscle architecture. Caecilians show a gradient between species with a long retroarticular process associated with a large and pennate-fibered m. interhyoideus posterior and species with a short process but long and parallel-fibered jaw adductors. Our results demonstrate the complexity of the relationship between form and function of this jaw system. Further studies that focus on factors such as gape distance or jaw velocity will be needed in order to fully understand the evolution of feeding mechanics in caecilians.
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Affiliation(s)
- Aurélien Lowie
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Barbara De Kegel
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Mark Wilkinson
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - John Measey
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Private Bag X1, 7602 Matieland, Stellenbosch, South Africa
| | - James C O'Reilly
- Department of Biomedical Sciences, Ohio University, Cleveland Campus, SPS-334C, Cleveland, OH 45701, USA
| | - Nathan J Kley
- Department of Anatomical Sciences, Health Sciences Center, T8-082, Stony Brook University, Stony Brook, NY 11794-8081, USA
| | - Philippe Gaucher
- USR 3456, CNRS, Centre de recherche de Montabo IRD, CNRS-Guyane, 97334 Cayenne, France
| | - Jonathan Brecko
- Royal Museum for Central Africa, Biological Collections and Data Management, 3080 Tervuren, Belgium
| | | | - Dominique Adriaens
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Anthony Herrel
- Ghent University, Department of Biology, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.,UMR 7179 C.N.R.S/M.N.H.N., Département d'Ecologie et de Gestion de la Biodiversité, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France
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Bergmann PJ, Berry DS. How head shape and substrate particle size affect fossorial locomotion in lizards. J Exp Biol 2021; 224:269100. [PMID: 34109985 DOI: 10.1242/jeb.242244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/10/2021] [Indexed: 12/28/2022]
Abstract
Granular substrates ranging from silt to gravel cover much of the Earth's land area, providing an important habitat for fossorial animals. Many of these animals use their heads to penetrate the substrate. Although there is considerable variation in head shape, how head shape affects fossorial locomotor performance in different granular substrates is poorly understood. Here, head shape variation for 152 species of fossorial lizards was quantified for head diameter, slope and pointiness of the snout. The force needed to penetrate different substrates was measured using 28 physical models spanning this evolved variation. Ten substrates were considered, ranging in particle size from 0.025 to 4 mm in diameter and consisting of spherical or angular particles. Head shape evolved in a weakly correlated manner, with snouts that were gently sloped being blunter. There were also significant clade differences in head shape among fossorial lizards. Experiments with physical models showed that as head diameter increased, absolute penetration force increased but force normalized by cross-sectional area decreased. Penetration force decreased for snouts that tapered more gradually and were pointier. Larger and angular particles required higher penetration forces, although intermediate size spherical particles, consistent with coarse sand, required the lowest force. Particle size and head diameter effect were largest, indicating that fossorial burrowers should evolve narrow heads and bodies, and select relatively fine particles. However, variation in evolved head shapes and recorded penetration forces suggests that kinematics of fossorial movement are likely an important factor in explaining evolved diversity.
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Affiliation(s)
- Philip J Bergmann
- Department of Biology, Clark University, 950 Main Street, Worcester, MA 01602, USA
| | - David S Berry
- Department of Biology, Clark University, 950 Main Street, Worcester, MA 01602, USA
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Morinaga G, Bergmann PJ. Evolution of fossorial locomotion in the transition from tetrapod to snake-like in lizards. Proc Biol Sci 2020; 287:20200192. [PMID: 32183623 DOI: 10.1098/rspb.2020.0192] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dramatic evolutionary transitions in morphology are often assumed to be adaptive in a new habitat. However, these assumptions are rarely tested because such tests require intermediate forms, which are often extinct. In vertebrates, the evolution of an elongate, limbless body is generally hypothesized to facilitate locomotion in fossorial and/or cluttered habitats. However, these hypotheses remain untested because few studies examine the locomotion of species ranging in body form from tetrapod to snake-like. Here, we address these functional hypotheses by testing whether trade-offs exist between locomotion in surface, fossorial and cluttered habitats in Australian Lerista lizards, which include multiple intermediate forms. We found that snake-like species penetrated sand substrates faster than more lizard-like species, representing the first direct support of the adaptation to fossoriality hypothesis. By contrast, body form did not affect surface locomotion or locomotion through cluttered leaf litter. Furthermore, all species with hindlimbs used them during both fossorial and surface locomotion. We found no evidence of a trade-off between fossorial and surface locomotion. This may be either because Lerista employed kinematic strategies that took advantage of both axial- and limb-based propulsion. This may have led to the differential occupation of their habitat, facilitating diversification of intermediate forms.
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Affiliation(s)
- Gen Morinaga
- Department of Biology, Clark University, Worcester, MA 01610, USA
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Dos Santos Lima Hohl L, Loguercio MFDC, Sicuro FL, Duarte de Barros-Filho J, Rocha-Barbosa O. Body and skull morphometric variations between two shovel-headed species of Amphisbaenia (Reptilia: Squamata) with morphofunctional inferences on burrowing. PeerJ 2017; 5:e3581. [PMID: 30057857 PMCID: PMC6062821 DOI: 10.7717/peerj.3581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/24/2017] [Indexed: 11/20/2022] Open
Abstract
Background Morphological descriptions comparing Leposternon microcephalum and L. scutigerum have been made previously. However, these taxa lack a formal quantitative morphological characterization, and comparative studies suggest that morphology and burrowing performance are be related. The excavatory movements of L. microcephalum have been described in detail. However, there is a lack of studies comparing locomotor patterns and/or performance among different amphisbaenids sharing the same skull shape. This paper presents the first study of comparative morphometric variations between two closely related amphisbaenid species, L. microcephalum and L. scutigerum, with functional inferences on fossorial locomotion efficiency. Methods Inter-specific morphometric variations were verified through statistical analyses of body and cranial measures of L. microcephalum and L. scutigerum specimens. Their burrowing activity was assessed through X-ray videofluoroscopy and then compared. The influence of morphological variation on the speed of digging was tested among Leposternon individuals. Results Leposternon microcephalum and L. scutigerum are morphometrically distinct species. The first is shorter and robust with a wider head while the other is more elongated and slim with a narrower head. They share the same excavatory movements. The animals analyzed reached relatively high speeds, but individuals with narrower skulls dug faster. A negative correlation between the speed and the width of skull was determined, but not with total length or diameter of the body. Discussion The morphometric differences between L. microcephalum and L. scutigerum are in accord with morphological variations previously described. Since these species performed the same excavation pattern, we may infer that closely related amphisbaenids with the same skull type would exhibit the same excavatory pattern. The negative correlation between head width and excavation speed is also observed in others fossorial squamates. The robustness of the skull is also related to compression force in L. microcephalum. Individuals with wider heads are stronger. Thus, we suggest trade-offs between excavation speed and compression force during burrowing in this species.
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Affiliation(s)
- Leandro Dos Santos Lima Hohl
- Departamento de Zoologia, Instituto de Biologia Roberto Alcantara Gomes, Laboratório de Zoologia de Vertebrados Tetrapoda-LAZOVERTE, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto de Biologia Roberto Alcantara Gomes, Programa de Pós-Graduação em Ecologia e Evolução, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.,Coordenação de Biologia, Centro Federal de Educação Tecnológica Celso Suckow da Fonseca-CEFET/RJ - Unidade Maracanã, Rio de Janeiro, Brazil
| | - Mariana Fiuza de Castro Loguercio
- Departamento de Zoologia, Instituto de Biologia Roberto Alcantara Gomes, Laboratório de Zoologia de Vertebrados Tetrapoda-LAZOVERTE, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernando Lencastre Sicuro
- Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, BIOVASC, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - José Duarte de Barros-Filho
- Departamento de Zoologia, Instituto de Biologia Roberto Alcantara Gomes, Laboratório de Zoologia de Vertebrados Tetrapoda-LAZOVERTE, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Oscar Rocha-Barbosa
- Departamento de Zoologia, Instituto de Biologia Roberto Alcantara Gomes, Laboratório de Zoologia de Vertebrados Tetrapoda-LAZOVERTE, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto de Biologia Roberto Alcantara Gomes, Programa de Pós-Graduação em Ecologia e Evolução, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
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