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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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2
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Ludington AJ, Hammond JM, Breen J, Deveson IW, Sanders KL. New chromosome-scale genomes provide insights into marine adaptations of sea snakes (Hydrophis: Elapidae). BMC Biol 2023; 21:284. [PMID: 38066641 PMCID: PMC10709897 DOI: 10.1186/s12915-023-01772-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Sea snakes underwent a complete transition from land to sea within the last ~ 15 million years, yet they remain a conspicuous gap in molecular studies of marine adaptation in vertebrates. RESULTS Here, we generate four new annotated sea snake genomes, three of these at chromosome-scale (Hydrophis major, H. ornatus and H. curtus), and perform detailed comparative genomic analyses of sea snakes and their closest terrestrial relatives. Phylogenomic analyses highlight the possibility of near-simultaneous speciation at the root of Hydrophis, and synteny maps show intra-chromosomal variations that will be important targets for future adaptation and speciation genomic studies of this system. We then used a strict screen for positive selection in sea snakes (against a background of seven terrestrial snake genomes) to identify genes over-represented in hypoxia adaptation, sensory perception, immune response and morphological development. CONCLUSIONS We provide the best reference genomes currently available for the prolific and medically important elapid snake radiation. Our analyses highlight the phylogenetic complexity and conserved genome structure within Hydrophis. Positively selected marine-associated genes provide promising candidates for future, functional studies linking genetic signatures to the marine phenotypes of sea snakes and other vertebrates.
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Affiliation(s)
- Alastair J Ludington
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
| | - Jillian M Hammond
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Darlinghurst, Australia
| | - James Breen
- Indigenous Genomics, Telethon Kids Institute, Adelaide, Australia
- John Curtin School of Medical Research, College of Health & Medicine, Australian National University, Canberra, Australia
| | - Ira W Deveson
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Darlinghurst, Australia
- Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Kate L Sanders
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
- The South Australian Museum, Adelaide, Australia.
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Riedel J, Schwarzkopf L. Variation in density, but not morphology, of cutaneous sensilla among body regions in nine species of Australian geckos. J Morphol 2022; 283:637-652. [PMID: 35174531 DOI: 10.1002/jmor.21462] [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: 12/10/2021] [Revised: 02/07/2022] [Accepted: 02/13/2022] [Indexed: 11/07/2022]
Abstract
Skin sense organs, i.e., cutaneous sensilla, are a well-known feature of the integument of squamate reptiles, and particularly geckos. They vary widely in morphology among species, and are thought to be mechanosensitive, associated with prey capture and handling, tail autotomy, and placement of the adhesive toepads in pad-bearing species. Some authors suggest that they may also sense abiotic environmental features, such as temperature, or humidity. Here, we describe the morphology and distribution of cutaneous sensilla among body regions of nine Australian gecko species, in four genera. We hypothesised that if sensilla morphology was distinct, or sensilla density high, around the mouth, on the tail, and on extremities, sensilla were likely used for these direct tactile functions. We found that sensilla morphology was uniform among body regions within species, but varied among species, while sensilla densities varied among species and body regions. In gecko species studied, sensilla density was highest on the labials and the dorsal tail scales, and low on the feet, head and body, providing strong support for the hypothesis that sensilla serve tactile mechanoreceptive functions for prey capture and handling and for predator avoidance, but not for toepad placement. We suggest sensilla density may be explained by mechanoreception, whereas structure may be influenced by other factors.
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Affiliation(s)
- Jendrian Riedel
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia.,Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany.,Herpetology Section, Zoological Research Museum Alexander Koenig (ZFMK) - Leibniz Institute for the Analysis of Biodiversity Change (LIB), Bonn, Germany
| | - Lin Schwarzkopf
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia
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Fujishima K, Sasai T, Hibino Y, Nishizawa H. Morphology, Diet, and Reproduction of Coastal Hydrophis Sea Snakes (Elapidae: Hydrophiinae) at Their Northern Distribution Limit. Zoolog Sci 2021; 38:405-415. [PMID: 34664915 DOI: 10.2108/zs210010] [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: 02/01/2021] [Accepted: 05/31/2021] [Indexed: 11/17/2022]
Abstract
The Ryukyu Archipelago represents the northern distribution limit for hydrophiine sea snakes, the largest group of marine reptiles. Ryukyuan sea snakes may have developed distinct local adaptations in morphology and ecology, but they have been poorly studied. We examined preserved specimens of 111 Hydrophismelanocephalusand 61 Hydrophis ornatusfrom the Ryukyu Archipelago to obtain data on morphology, diet, and reproduction. Sexual size dimorphism was detected in H. melanocephalus (mean ± standard deviation of adult snout-vent length: SVL, females 1062 ± 141 mm vs. males 959 ± 96 mm) but not in H. ornatus. Female H. melanocephalus had larger head widths and shorter tail lengths relative to SVL compared to males. Relative girth was low in neonates of both species (1.0-1.3), but increased in adults to about 1.7-2.6 in H. melanocephalus and 1.3-1.8 in female H. ornatus. Stomach contents of H. melanocephalus consisted of ophichthid and congrid eels, a sand diver, and gobies, whereas in H. ornatus, gobies and a goat fish were found. Litter size of three reproductive H. melanocephalus ranged from five to seven, and parturition seems to occur from August to October. Litter size of six H. ornatus ranged from two to seven, and was correlated with maternal SVL. Parturition in H. ornatus probably occurs around November. Different selective forces related to locomotion, feeding and predation risk, which influence the pregnant mother and neonates, may have resulted in having few, long but slender offspring that show positive allometric growth in hind-body girth.
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Affiliation(s)
- Kanta Fujishima
- Graduate School of Informatics, Kyoto University, Yoshida Hommachi, Kyoto 606-8501, Japan,
| | - Takahide Sasai
- Graduate School of Engineering and Science, University of the Ryukyus, Nishihara-cho, Okinawa 903-0213, Japan.,Okinawa Churashima Foundation, Motobu-cho, Okinawa 905-0206, Japan
| | - Yusuke Hibino
- Kitakyushu Museum of Natural History and Human History, Kitakyushu, Fukuoka 805-0071, Japan
| | - Hideaki Nishizawa
- Graduate School of Informatics, Kyoto University, Yoshida Hommachi, Kyoto 606-8501, Japan
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García-Cobos D, Gómez-Sánchez DA, Crowe-Riddell JM, Sanders KL, Molina J. Ecological and sexual roles of scale mechanoreceptors in two species of Neotropical freshwater snake (Dipsadinae: Helicops). Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Understanding the roles of ecological and sexual selection in the variation of sensory systems may elucidate aspects of the natural history of organisms. Little is known about the evolution of mechanoreception in snakes and how the function and structure of mechanoreceptors vary between species or sexes. Here, we describe the internal and external morphology of cephalic mechanoreceptor sensilla and quantify inter- and intraspecific variation in four sensilla traits of two freshwater snake species that differ in their habitat and diet preferences, Helicops pastazae and Helicops angulatus, by combining scanning electron microscopy (SEM), histological techniques and image analyses. SEM showed sensilla as prominent evaginations of the epidermis surrounded by concentric rings, with H. pastazae having larger and more heterogeneous sensilla. In both species, histology showed a reduction in the outer epidermal layer above the sensilla with a grouping of dermally derived central cells below it. Higher values of sensilla traits were found in H. pastazae, except for the chin-shields. We also found that males of both species had significantly higher values of sensilla traits on all of the scales examined. We hypothesize that the variation in both qualitative and quantitative traits in scale sensilla might be a consequence of differences in foraging and/or reproductive strategies between species and sexes.
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Affiliation(s)
- Daniela García-Cobos
- Subdirección de Investigaciones, Colecciones Biológicas, Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Claustro de San Agustín, Villa de Leyva, Boyacá, Colombia
- Museo de Historia Natural C.J. Marinkelle, Universidad de los Andes, Departamento de Ciencias Biológicas, Bogotá D.C., Colombia
| | - Diego A Gómez-Sánchez
- Reserva Natural Rey Zamuro – Matarredonda, San Martín de los Llanos, Dpto. Meta, Colombia
| | - Jenna M Crowe-Riddell
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48100, USA
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Kate L Sanders
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Jorge Molina
- Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Universidad de los Andes, Departamento de Ciencias Biológicas, Bogotá D.C., Colombia
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Crowe-Riddell JM, Jolly CJ, Goiran C, Sanders KL. The sex life aquatic: sexually dimorphic scale mechanoreceptors and tactile courtship in a sea snake Emydocephalus annulatus (Elapidae: Hydrophiinae). Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Evolutionary transitions from terrestrial to aquatic habitats involve major selective shifts in animal signalling systems. Entirely marine snakes face two challenges during underwater social interactions: (1) finding mates when pheromones are diffused by water currents; and, once a mate is located, (2) maintaining contact and co-ordinating mating when tactile cues are diminished by buoyancy force. We explore the potential tactile roles of scale protuberances in the mating of turtle-headed sea snakes [Emydocephalus annulatus (Hydrophiinae)] by investigating sexual dimorphism in museum specimens (N = 59). In addition to the previously noted rostral spine on the snout, we found that mature males have enlarged structures located on the chin (genial knobs) and near the cloaca (anal knobs). Ultrastructural data indicates that the rostral spine is comprised of thickened epidermal and dermal layers, similar to rugosities on the body, and likely provide stimulation to the female during prodding by the male. In contrast, the genial and anal knobs have dermally derived central cells indicative of enlarged scale mechanoreceptors (i.e. sensilla). We suggest that these mechanoreceptors are critical to mating success: genial knobs may help amorous males orient to the direction of female motion; whereas, and anal knobs likely give somatosensory feedback for cloacal alignment
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Affiliation(s)
- Jenna M Crowe-Riddell
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor MI, USA
| | - Chris J Jolly
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
- Museum & Art Gallery of the Northern Territory, Darwin, NT, Australia
- Australian Museum Research Institute, Australian Museum, Sydney, NSW, Australia
| | - Claire Goiran
- LabEx Corail and ISEA, Université de La Nouvelle-Calédonie, BP R4, Nouméa Cedex, New Caledonia
| | - Kate L Sanders
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
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Palci A, Seymour RS, Van Nguyen C, Hutchinson MN, Lee MSY, Sanders KL. Novel vascular plexus in the head of a sea snake (Elapidae, Hydrophiinae) revealed by high-resolution computed tomography and histology. ROYAL SOCIETY OPEN SCIENCE 2019; 6:191099. [PMID: 31598325 PMCID: PMC6774945 DOI: 10.1098/rsos.191099] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/01/2019] [Indexed: 05/03/2023]
Abstract
Novel phenotypes are often linked to major ecological transitions during evolution. Here, we describe for the first time an unusual network of large blood vessels in the head of the sea snake Hydrophis cyanocinctus. MicroCT imaging and histology reveal an intricate modified cephalic vascular network (MCVN) that underlies a broad area of skin between the snout and the roof of the head. It is mostly composed of large veins and sinuses and converges posterodorsally into a large vein (sometimes paired) that penetrates the skull through the parietal bone. Endocranially, this blood vessel leads into the dorsal cerebral sinus, and from there, a pair of large veins depart ventrally to enter the brain. We compare the condition observed in H. cyanocinctus with that of other elapids and discuss the possible functions of this unusual vascular network. Sea snakes have low oxygen partial pressure in their arterial blood that facilitates cutaneous respiration, potentially limiting the availability of oxygen to the brain. We conclude that this novel vascular structure draining directly to the brain is a further elaboration of the sea snakes' cutaneous respiratory anatomy, the most likely function of which is to provide the brain with an additional supply of oxygen.
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Affiliation(s)
- Alessandro Palci
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
| | - Roger S. Seymour
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Cao Van Nguyen
- Institute of Oceanography, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Mark N. Hutchinson
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
| | - Michael S. Y. Lee
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
| | - Kate L. Sanders
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
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Chapuis L, Kerr CC, Collin SP, Hart NS, Sanders KL. Underwater hearing in sea snakes (Hydrophiinae): first evidence of auditory evoked potential thresholds. ACTA ACUST UNITED AC 2019; 222:222/14/jeb198184. [PMID: 31345949 DOI: 10.1242/jeb.198184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/01/2019] [Indexed: 11/20/2022]
Abstract
The viviparous sea snakes (Hydrophiinae) are a secondarily aquatic radiation of more than 60 species that possess many phenotypic adaptations to marine life. However, virtually nothing is known of the role and sensitivity of hearing in sea snakes. This study investigated the hearing sensitivity of the fully marine sea snake Hydrophis stokesii by measuring auditory evoked potential (AEP) audiograms for two individuals. AEPs were recorded from 40 Hz (the lowest frequency tested) up to 600 Hz, with a peak in sensitivity identified at 60 Hz (163.5 dB re. 1 µPa or 123 dB re. 1 µm s-2). Our data suggest that sea snakes are sensitive to low-frequency sounds but have relatively low sensitivity compared with bony fishes and marine turtles. Additional studies are required to understand the role of sound in sea snake life history and further assess these species' vulnerability to anthropogenic noise.
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Affiliation(s)
- Lucille Chapuis
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK .,Oceans Graduate School and the UWA Oceans Institute, The University of Western Australia, Perth, WA 6009, Australia
| | - Caroline C Kerr
- Oceans Graduate School and the UWA Oceans Institute, The University of Western Australia, Perth, WA 6009, Australia
| | - Shaun P Collin
- Oceans Graduate School and the UWA Oceans Institute, The University of Western Australia, Perth, WA 6009, Australia.,School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia
| | - Nathan S Hart
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Kate L Sanders
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
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