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Barrionuevo JS, Pucci Alcaide F. Back to the water: Tongue morphology associated to contrasting lifestyles in two Andean frogs of the genus Telmatobius. ZOOLOGY 2024; 163:126157. [PMID: 38428124 DOI: 10.1016/j.zool.2024.126157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 02/05/2024] [Accepted: 02/17/2024] [Indexed: 03/03/2024]
Abstract
The evolution of the tongue in tetrapods is associated with feeding in the terrestrial environment. This study analyzes the tongue morphology of two closely related frog species, Telmatobius oxycephalus and T. rubigo, which exhibit contrasting feeding mechanisms. Telmatobius oxycephalus, a semi-aquatic species, relies on its tongue to capture terrestrial prey whereas T. rubigo, a secondarily aquatic species, uses suction feeding not involving the tongue. Through anatomical, histological and scanning electron microscopy analyses, we revealed remarkable differences in tongue morphology between these species. Telmatobius oxycephalus exhibits a well-developed tongue whose dorsal epithelium has numerous and slender filiform papillae. The epithelial cells of the papillae are protruded and have a complex array of microridges. In contrast, T. rubigo possesses a reduced tongue with flat and less numerous filiform papillae. The epithelial cells are completely flat and lack microridges. These findings highlight the remarkable adaptability of lingual morphology in Telmatobius to respond to the contrasting ecological niches and prey capture mechanisms. This study sheds light on the relationship between tongue shape and the different functional demands, contributing to our understanding of the evolution of prey capture mechanisms in amphibians.
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Affiliation(s)
- J Sebastián Barrionuevo
- Área Herpetología, Unidad Ejecutora Lillo (CONICET-Fundación Miguel Lillo), Miguel Lillo 251, S. M. de Tucumán, Argentina; Fundación Miguel Lillo, Miguel Lillo 251, S. M. de Tucumán, Argentina.
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2
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Yang Y, Xie Y, Liu J, Li Y, Chen F. 3D-Printed Origami Actuators for a Multianimal-Inspired Soft Robot with Amphibious Locomotion and Tongue Hunting. Soft Robot 2024. [PMID: 38330424 DOI: 10.1089/soro.2023.0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024] Open
Abstract
The field of soft robotics is rapidly evolving, and there is a growing interest in developing soft robots with bioinspired features for use in various applications. This research presented the design and development of 3D-printed origami actuators for a soft robot with amphibious locomotion and tongue hunting capabilities. Two different types of programmable origami actuators were designed and manufactured, namely Z-shaped and twist tower actuators. In addition, two actuator variations were developed based on the Z-shaped actuator, including the pelvic fin and the coiling/uncoiling types. The Z-shaped actuators were used for the rear legs to facilitate the locomotion of the water-like frogs. Meanwhile, the twisted tower actuators were used for the rotation joints in the forelegs and for locomotion on land. The pelvic fin actuator was developed to imitate the land locomotion of the mudskipper, and the coiling/uncoiling actuator was designed for tongue hunting motion. The origami actuators and soft robot prototype were tested through a series of experiments, which showed that the robot was capable of efficiently moving in water and on land and performing tongue hunting motions. Our results demonstrate the effectiveness of these actuators in producing the desired motions and provide insights into the potential of applying 3D-printed origami actuators in the development of soft robots with bioinspired features.
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Affiliation(s)
- Yang Yang
- School of Automation, Nanjing University of Information Science and Technology, Nanjing, China
- Jiangsu Province Engineering Research Center of Intelligent Meteorological Exploration Robot, Nanjing University of Information Science and Technology, Nanjing, China
- Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science and Technology, Nanjing, China
| | - Yuan Xie
- School of Automation, Nanjing University of Information Science and Technology, Nanjing, China
- Jiangsu Province Engineering Research Center of Intelligent Meteorological Exploration Robot, Nanjing University of Information Science and Technology, Nanjing, China
| | - Jia Liu
- School of Automation, Nanjing University of Information Science and Technology, Nanjing, China
- Jiangsu Province Engineering Research Center of Intelligent Meteorological Exploration Robot, Nanjing University of Information Science and Technology, Nanjing, China
- Tianchang Research Institute of NUIST, Tianchang, Anhui, China
| | - Yunquan Li
- Shien-Ming Wu School of Intelligent Engineering, South China University of Technology, Guangzhou, China
| | - Feifei Chen
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University and Robotics Institute, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
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3
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Krings W, Gorb SN. Particle binding capacity of snail saliva. J Chem Phys 2023; 159:185101. [PMID: 37955324 DOI: 10.1063/5.0176668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 10/20/2023] [Indexed: 11/14/2023] Open
Abstract
Gastropods forage with their radula, a thin chitinous membrane with embedded teeth, which scratch across the substrate to lose food particles. During this interaction, the risk of loosening particles is obvious without having a specialized mechanism holding them on the tooth surface. As mucus secretions are essential in molluscan life cycles and the locomotion and attachment gels are known to have an instant high adhesion, we have hypothesized that the saliva could support particle retention during feeding. As adhesion of snail saliva was not studied before, we present here an experimental setup to test its particle-binding capacity using a large land snail (Lissachatina fulica, Stylommatophora, Heterobranchia). This experiment was also applied to the gels produced by the snail foot for comparison and can be potentially applied to various fluids present at a small volume in the future. We found, that the saliva has high particle retention capacity that is comparable to the foot glue of the snail. To gain some insight into the properties of the saliva, we additionally studied it in the scanning electron microscope, estimated its viscosity in a de-wetting experiment, and investigated its elemental composition using energy dispersive X-ray spectroscopy reveling higher contents of Ca, Zn and other potential cross-linkers similar to those found in the glue.
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Affiliation(s)
- Wencke Krings
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Liebigstraße 12, 04103 Leipzig, Germany
- Department of Electron Microscopy, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
- Department of Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
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Melrose J. High Performance Marine and Terrestrial Bioadhesives and the Biomedical Applications They Have Inspired. Molecules 2022; 27:molecules27248982. [PMID: 36558114 PMCID: PMC9783952 DOI: 10.3390/molecules27248982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/10/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
This study has reviewed the naturally occurring bioadhesives produced in marine and freshwater aqueous environments and in the mucinous exudates of some terrestrial animals which have remarkable properties providing adhesion under difficult environmental conditions. These bioadhesives have inspired the development of medical bioadhesives with impressive properties that provide an effective alternative to suturing surgical wounds improving closure and healing of wounds in technically demanding tissues such as the heart, lung and soft tissues like the brain and intestinal mucosa. The Gecko has developed a dry-adhesive system of exceptional performance and has inspired the development of new generation re-usable tapes applicable to many medical procedures. The silk of spider webs has been equally inspiring to structural engineers and materials scientists and has revealed innovative properties which have led to new generation technologies in photonics, phononics and micro-electronics in the development of wearable biosensors. Man made products designed to emulate the performance of these natural bioadhesive molecules are improving wound closure and healing of problematic lesions such as diabetic foot ulcers which are notoriously painful and have also found application in many other areas in biomedicine. Armed with information on the mechanistic properties of these impressive biomolecules major advances are expected in biomedicine, micro-electronics, photonics, materials science, artificial intelligence and robotics technology.
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Affiliation(s)
- James Melrose
- Raymond Purves Bone and Joint Research Laboratory, Kolling Institute, Faculty of Medicine and Health, University of Sydney at Royal North Shore Hospital, Northern Sydney Local Health District, St. Leonards, NSW 2065, Australia;
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Sydney Medical School, Northern Campus, The University of Sydney, St. Leonards, NSW 2065, Australia
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5
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Clement AM, Mensforth CL, Challands TJ, Collin SP, Long JA. Brain Reconstruction Across the Fish-Tetrapod Transition; Insights From Modern Amphibians. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.640345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The fish-tetrapod transition (which incorporates the related fin-limb and water-land transitions) is celebrated as one of the most important junctions in vertebrate evolution. Sarcopterygian fishes (the “lobe-fins”) are today represented by lungfishes and coelacanths, but during the Paleozoic they were much more diverse. It was some of these sarcopterygians, a lineage of the tetrapodomorph fishes, that gave rise to tetrapods (terrestrial vertebrates with limbs bearing digits). This spectacular leap took place during the Devonian Period. Due to the nature of preservation, it is the hard parts of an animal’s body that are most likely to fossilize, while soft tissues such as muscular and brain tissues, typically fail to do so. Thus, our understanding of the adaptations of the hard skeletal structures of vertebrates is considerably greater than that of the soft tissue systems. Fortunately, the braincases of early vertebrates are often ossified and thereby have the potential to provide detailed morphological information. However, the correspondence between brain and endocast (an internal mold of the cavity) has historically been considered poor in most “lower” vertebrates and consequently neglected in such studies of brain evolution. Despite this, recent work documenting the spatial relationship in extant basal sarcopterygians (coelacanth, lungfish, axolotl, and salamander) has highlighted that this is not uniformly the case. Herein, we quantify and illustrate the brain-endocast relationship in four additional extant basal tetrapod exemplars: neobatrachian anurans (frogs) Breviceps poweri and Ceratophrys ornata; and gymnophionans (caecilians) Gegeneophis ramaswamii and Rhinatrema bivittatum. We show that anurans and caecilians appear to have brains that fill their endocasts to a similar degree to that of lungfishes and salamanders, but not coelacanth. Ceratophrys has considerably lower correspondence between the brain and endocast in the olfactory tract and mesencephalic regions, while Breviceps has low correspondence along its ventral endocranial margin. The brains of caecilians reflect their endocasts most closely (vol. ∼70%). The telencephalon is tightly fitted within the endocast in all four taxa. Our findings highlight the need to adequately assess the brain-endocast relationship in a broad range of vertebrates, in order to inform neural reconstructions of fossil taxa using the Extant Phylogenetic Bracket approach and future studies of brain evolution.
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Kunisch S, Blüml V, Schwaha T, Beisser CJ, Handschuh S, Lemell P. Digital dissection of the head of the frogs Calyptocephalella gayi and Leptodactylus pentadactylus with emphasis on the feeding apparatus. J Anat 2021; 239:391-404. [PMID: 33713453 PMCID: PMC8273601 DOI: 10.1111/joa.13426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 11/26/2022] Open
Abstract
Micro‐computed tomography (microCT) of small animals has led to a more detailed and more accurate three‐dimensional (3D) view on different anatomical structures in the last years. Here, we present the cranial anatomy of two frog species providing descriptions of bone structures and soft tissues of the feeding apparatus with comments to possible relations to habitat and feeding ecology. Calyptocephalella gayi, known for its aquatic lifestyle, is not restricted to aquatic feeding but also feeds terrestrially using lingual prehension. This called for a detailed investigation of the morphology of its feeding apparatus and a comparison to a fully terrestrial species that is known to feed by lingual prehension such as Leptodactylus pentadactylus. These two frog species are of similar size, feed on similar diet but within different main habitats. MicroCT scans of both species were conducted in order to reconstruct the complete anatomical condition of the whole feeding apparatus for the first time. Differences in this regard are evident in the tongue musculature, which in L. pentadactylus is more massively built and with a broader interdigitating area of the two main muscles, the protractor musculus genioglossus and the retractor musculus hyoglossus. In contrast, the hyoid retractor (m. sternohyoideus) is more massive in the aquatic species C. gayi. Moreover, due to the different skull morphology, the origins of two of the five musculi adductores vary between the species. This study brings new insights into the relation of the anatomy of the feeding apparatus to the preferred feeding method via 3D imaging techniques. Contrary to the terrestrially feeding L. pentadactylus, the skeletal and muscular adaptations of the aquatic species C. gayi provide a clear picture of necessities prescribed by the habitat. Nevertheless, by keeping a certain amount of flexibility of the design of its feeding apparatus, C. gayi is able to employ various methods of feeding.
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Affiliation(s)
- Stephanie Kunisch
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Valentin Blüml
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Thomas Schwaha
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Christian Josef Beisser
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | | | - Patrick Lemell
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
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McElroy MT, Donoso DA. Ant Morphology Mediates Diet Preference in a Neotropical Toad (Rhinella alata). COPEIA 2019. [DOI: 10.1643/ch-18-162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Matthew T. McElroy
- Environmental Science, Policy, and Management, University of California, Berkeley, California 94720;
| | - David A. Donoso
- Departamento de Biología, Escuela Politécnica Nacional, Quito, Ecuador; . Send reprint requests to this address
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Kehl CE, Wu J, Lu S, Neustadter DM, Drushel RF, Smoldt RK, Chiel HJ. Soft-surface grasping: radular opening in Aplysia californica. J Exp Biol 2019; 222:jeb191254. [PMID: 31350299 PMCID: PMC6739808 DOI: 10.1242/jeb.191254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 07/01/2019] [Indexed: 12/22/2022]
Abstract
Grasping soft, irregular material is challenging both for animals and robots. The feeding systems of many animals have adapted to this challenge. In particular, the feeding system of the marine mollusk Aplysia californica, a generalist herbivore, allows it to grasp and ingest seaweeds of varying shape, texture and toughness. On the surface of the grasper of A. californica is a structure known as the radula, a thin flexible cartilaginous sheet with fine teeth. Previous in vitro studies suggested that intrinsic muscles, I7, are responsible for opening the radula. Lesioning I7 in vivo does not prevent animals from grasping and ingesting food. New in vitro studies demonstrate that a set of fine muscle fibers on the ventral surface of the radula - the sub-radular fibers (SRFs) - mediate opening movements even if the I7 muscles are absent. Both in vitro and in vivo lesions demonstrate that removing the SRFs leads to profound deficits in radular opening, and significantly reduces feeding efficiency. A theoretical biomechanical analysis of the actions of the SRFs suggests that they induce the radular surface to open around a central crease in the radular surface and to arch the radular surface, allowing it to softly conform to irregular material. A three-dimensional model of the radular surface, based on in vivo observations and magnetic resonance imaging of intact animals, provides support for the biomechanical analysis. These results suggest how a soft grasper can work during feeding, and suggest novel designs for artificial soft graspers.
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Affiliation(s)
- Catherine E Kehl
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Joey Wu
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sisi Lu
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | | | - Richard F Drushel
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Rebekah K Smoldt
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Hillel J Chiel
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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9
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Collings AJ, Richards CT. Digital dissection of the pelvis and hindlimb of the red-legged running frog, Phlyctimantis maculatus, using Diffusible Iodine Contrast Enhanced computed microtomography (DICE μCT). PeerJ 2019; 7:e7003. [PMID: 31211012 PMCID: PMC6557250 DOI: 10.7717/peerj.7003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/23/2019] [Indexed: 12/26/2022] Open
Abstract
Background The current study applies both traditional and Diffusible Iodine Contrast Enhanced computed microtomography (DICE µCT) techniques to reveal the musculoskeletal anatomy of Phlyctimantis maculatus. DICE µCT has emerged as a powerful tool to visualise intricate musculoskeletal anatomy. By generating 3D digital models, anatomical analyses can be conducted non-destructively, preserving the in situ 3D topography of the system, therefore eliminating some of the drawbacks associated with traditional methods. We aim to describe the musculature of the spine, pelvis, and hindlimb, compare the musculoskeletal anatomy and pelvic morphology of P. maculatus with functionally diverse frogs, and produce 3D digital anatomy reference data. Method An adult frog was stained using an aqueous Lugol’s solution and scanned in a SkyScan1176 in vivo µCT scanner. Scan images were reconstructed, resampled, and digitally segmented to produce a 3D model. A further adult female frog was dissected traditionally for visualisation of tendinous insertions. Results Our work revealed three main findings: (1) P. maculatus has similar gross muscular anatomy to Rana catesbeiana (bullfrog) but is distinct from those species that exhibit ancestral traits (leopelmids) and those that are highly specialised (pipids), (2) P. maculatus’s pelvic anatomy best fits the description of Emerson’s walking/hopping pelvic morphotype IIA, and (3) a split in the semimembranosus and gracilis major muscles is consistent with the reported myology in other anuran species. Discussion While DICE µCT methods were instrumental in characterising the 3D anatomy, traditional dissection was still required to visualise important structures such as the knee aponeurosis, tendinous insertions, and fasciae. Nonetheless, the anatomical data presented here marks the first detailed digital description of an arboreal and terrestrial frog. Further, our digital model presents P. maculatus as a good frog model system and as such has formed a crucial platform for further functional analysis within the anuran pelvis and hindlimb.
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Affiliation(s)
- Amber J Collings
- School of Science Engineering and Design, Teesside University, Middlesbrough, United Kingdom.,Structure and Motion Laboratory, Royal Veterinary College, London, United Kingdom
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10
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Iwasaki SI, Erdoğan S, Asami T. Evolutionary Specialization of the Tongue in Vertebrates: Structure and Function. FEEDING IN VERTEBRATES 2019. [DOI: 10.1007/978-3-030-13739-7_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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11
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Heiss E, Aerts P, Van Wassenbergh S. Aquatic-terrestrial transitions of feeding systems in vertebrates: a mechanical perspective. ACTA ACUST UNITED AC 2018; 221:221/8/jeb154427. [PMID: 29695537 DOI: 10.1242/jeb.154427] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transitions to terrestrial environments confront ancestrally aquatic animals with several mechanical and physiological problems owing to the different physical properties of water and air. As aquatic feeders generally make use of flows of water relative to the head to capture, transport and swallow food, it follows that morphological and behavioral changes were inevitably needed for the aquatic animals to successfully perform these functions on land. Here, we summarize the mechanical requirements of successful aquatic-to-terrestrial transitions in food capture, transport and swallowing by vertebrates and review how different taxa managed to fulfill these requirements. Amphibious ray-finned fishes show a variety of strategies to stably lift the anterior trunk, as well as to grab ground-based food with their jaws. However, they still need to return to the water for the intra-oral transport and swallowing process. Using the same mechanical perspective, the potential capabilities of some of the earliest tetrapods to perform terrestrial feeding are evaluated. Within tetrapods, the appearance of a mobile neck and a muscular and movable tongue can safely be regarded as key factors in the colonization of land away from amphibious habitats. Comparative studies on taxa including salamanders, which change from aquatic feeders as larvae to terrestrial feeders as adults, illustrate remodeling patterns in the hyobranchial system that can be linked to its drastic change in function during feeding. Yet, the precise evolutionary history in form and function of the hyolingual system leading to the origin(s) of a muscular and adhesive tongue remains unknown.
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Affiliation(s)
- Egon Heiss
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University Jena, Erbertstr. 1, 07743, Jena, Germany
| | - Peter Aerts
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.,Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, B-9000, Ghent, Belgium
| | - Sam Van Wassenbergh
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.,Département Adaptations du Vivant, Muséum National d' Histoire Naturelle, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France
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12
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Noel AC, Guo HY, Mandica M, Hu DL. Frogs use a viscoelastic tongue and non-Newtonian saliva to catch prey. J R Soc Interface 2017; 14:rsif.2016.0764. [PMID: 28148766 DOI: 10.1098/rsif.2016.0764] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/14/2016] [Indexed: 11/12/2022] Open
Abstract
Frogs can capture insects, mice and even birds using only their tongue, with a speed and versatility unmatched in the world of synthetic materials. How can the frog tongue be so sticky? In this combined experimental and theoretical study, we perform a series of high-speed films, material tests on the tongue, and rheological tests of the frog saliva. We show that the tongue's unique stickiness results from a combination of a soft, viscoelastic tongue coupled with non-Newtonian saliva. The tongue acts like a car's shock absorber during insect capture, absorbing energy and so preventing separation from the insect. The shear-thinning saliva spreads over the insect during impact, grips it firmly during tongue retraction, and slides off during swallowing. This combination of properties gives the tongue 50 times greater work of adhesion than known synthetic polymer materials such as the sticky-hand toy. These principles may inspire the design of reversible adhesives for high-speed application.
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Affiliation(s)
- Alexis C Noel
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hao-Yuan Guo
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Mark Mandica
- Atlanta Botanical Garden, Atlanta, GA 30309, USA
| | - David L Hu
- School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA .,School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
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13
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Wolff JO, Řezáč M, Krejčí T, Gorb SN. Hunting with sticky tape: functional shift in silk glands of araneophagous ground spiders (Gnaphosidae). J Exp Biol 2017; 220:2250-2259. [DOI: 10.1242/jeb.154682] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/09/2017] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Foraging is one of the main evolutionary driving forces shaping the phenotype of organisms. In predators, a significant, though understudied, cost of foraging is the risk of being injured by struggling prey. Hunting spiders that feed on dangerous prey like ants or other spiders are an extreme example of dangerous feeding, risking their own life over a meal. Here, we describe an intriguing example of the use of attachment silk (piriform silk) for prey immobilization that comes with the costs of reduced silk anchorage function, increased piriform silk production and additional modifications of the extrusion structures (spigots) to prevent their clogging. We show that the piriform silk of gnaphosids is very stretchy and tough, which is an outstanding feat for a functional glue. This is gained by the combination of an elastic central fibre and a bi-layered glue coat consisting of aligned nanofibrils. This represents the first tensile test data on the ubiquitous piriform gland silk, adding an important puzzle piece to the mechanical catalogue of silken products in spiders.
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Affiliation(s)
- Jonas O. Wolff
- Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1–9, Kiel D-24118, Germany
- Behavioural Ecology, Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Milan Řezáč
- Biodiversity Lab, Crop Research Institute, Drnovská 507, Prague 6 – Ruzyně CZ-16106, Czechia
| | - Tomáš Krejčí
- Faculty of Environmental Sciences, Czech University of Life Sciences, Kamýcká 129, Prague 6 – Suchdol CZ-16521, Czechia
| | - Stanislav N. Gorb
- Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1–9, Kiel D-24118, Germany
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14
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Porro LB, Richards CT. Digital dissection of the model organism Xenopus laevis using contrast-enhanced computed tomography. J Anat 2017; 231:169-191. [PMID: 28547827 DOI: 10.1111/joa.12625] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2017] [Indexed: 01/03/2023] Open
Abstract
The African clawed frog, Xenopus laevis, is one of the most widely used model organisms in biological research. However, the most recent anatomical description of X. laevis was produced nearly a century ago. Compared with other anurans, pipid frogs - including X. laevis - exhibit numerous unusual morphological features; thus, anatomical descriptions of more 'typical' frogs do not detail many aspects of X. laevis skeletal and soft-tissue morphology. The relatively new method of using iodine-based agents to stain soft tissues prior to high-resolution X-ray imaging has several advantages over gross dissection, such as enabling dissection of very small and fragile specimens, and preserving the three-dimensional topology of anatomical structures. Here, we use contrast-enhanced computed tomography to produce a high-resolution three-dimensional digital dissection of a post-metamorphic X. laevis to successfully visualize: skeletal and muscular anatomy; the nervous, respiratory, digestive, excretory and reproductive systems; and the major sense organs. Our digital dissection updates and supplements previous anatomical descriptions of this key model organism, and we present the three-dimensional data as interactive portable document format (PDF) files that are easily accessible and freely available for research and educational purposes. The data presented here hold enormous potential for applications beyond descriptive purposes, particularly for biological researchers using this taxon as a model organism, comparative anatomy and biomechanical modelling.
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Affiliation(s)
- Laura B Porro
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, Hertfordshire, UK
| | - Christopher T Richards
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, Hertfordshire, UK
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15
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Heiss E, Handschuh S, Aerts P, Van Wassenbergh S. A tongue for all seasons: extreme phenotypic flexibility in salamandrid newts. Sci Rep 2017; 7:1006. [PMID: 28432290 PMCID: PMC5430857 DOI: 10.1038/s41598-017-00674-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/08/2017] [Indexed: 01/23/2023] Open
Abstract
Many organisms faced with seasonally fluctuating abiotic and biotic conditions respond by altering their phenotype to account for the demands of environmental changes. Here we discovered that newts, which switch seasonally between an aquatic and terrestrial lifestyle, grow a complex adhesive system on their tongue pad consisting of slender lingual papillae and mucus-producing cells to increase the efficiency of prey capture as they move from water onto land. The adhesive system is reduced again as newts switch back to their aquatic stage, where they use suction to capture prey. As suction performance is also enhanced seasonally by reshaping of the mouth due to the growth of labial lobes, our results show that newts are exceptional in exhibiting phenotypic flexibility in two alternating components (i.e. tongue pad and labial lobes) within a single functional system, and suggest that this form of phenotypic flexibility demands complex genetic regulation.
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Affiliation(s)
- Egon Heiss
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich-Schiller-University Jena, Erbertstr. 1, 07743, Jena, Germany.
| | - Stephan Handschuh
- VetCore Facility for Research, Imaging Unit, University for Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Peter Aerts
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.,Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, B-9000, Ghent, Belgium
| | - Sam Van Wassenbergh
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium.,Departement d'Ecologie et de Gestion de la Biodiversité, Muséum National d' Histoire Naturelle, 57 rue Cuvier, Case postale 55, 75231, Paris Cedex 5, France
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16
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Bribiesca-Contreras F, Sellers WI. Three-dimensional visualisation of the internal anatomy of the sparrowhawk ( Accipiter nisus) forelimb using contrast-enhanced micro-computed tomography. PeerJ 2017; 5:e3039. [PMID: 28316884 PMCID: PMC5356476 DOI: 10.7717/peerj.3039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 01/27/2017] [Indexed: 12/20/2022] Open
Abstract
Background Gross dissection is a widespread method for studying animal anatomy, despite being highly destructive and time-consuming. X-ray computed tomography (CT) has been shown to be a non-destructive alternative for studying anatomical structures. However, in the past it has been limited to only being able to visualise mineralised tissues. In recent years, morphologists have started to use traditional X-ray contrast agents to allow the visualisation of soft tissue elements in the CT context. The aim of this project is to assess the ability of contrast-enhanced micro-CT (μCT) to construct a three-dimensional (3D) model of the musculoskeletal system of the bird wing and to quantify muscle geometry and any systematic changes due to shrinkage. We expect that this reconstruction can be used as an anatomical guide to the sparrowhawk wing musculature and form the basis of further biomechanical analysis of flight. Methods A 3% iodine-buffered formalin solution with a 25-day staining period was used to visualise the wing myology of the sparrowhawk (Accipiter nisus). μCT scans of the wing were taken over the staining period until full penetration of the forelimb musculature by iodine was reached. A 3D model was reconstructed by manually segmenting out the individual elements of the avian wing using 3D visualisation software. Results Different patterns of contrast were observed over the duration of the staining treatment with the best results occurring after 25 days of staining. Staining made it possible to visualise and identify different elements of the soft tissue of the wing. Finally, a 3D reconstruction of the musculoskeletal system of the sparrowhawk wing is presented and numerical data of muscle geometry is compared to values obtained by dissection. Discussion Contrast-enhanced μCT allows the visualisation and identification of the wing myology of birds, including the smaller muscles in the hand, and provides a non-destructive way for quantifying muscle volume with an accuracy of 96.2%. By combining contrast-enhanced μCT with 3D visualisation techniques, it is possible to study the individual muscles of the forelimb in their original position and 3D design, which can be the basis of further biomechanical analysis. Because the stain can be washed out post analysis, this technique provides a means of obtaining quantitative muscle data from museum specimens non-destructively.
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Affiliation(s)
| | - William I Sellers
- Faculty of Science and Engineering, University of Manchester , Manchester , UK
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17
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Gignac PM, Kley NJ, Clarke JA, Colbert MW, Morhardt AC, Cerio D, Cost IN, Cox PG, Daza JD, Early CM, Echols MS, Henkelman RM, Herdina AN, Holliday CM, Li Z, Mahlow K, Merchant S, Müller J, Orsbon CP, Paluh DJ, Thies ML, Tsai HP, Witmer LM. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues. J Anat 2016; 228:889-909. [PMID: 26970556 PMCID: PMC5341577 DOI: 10.1111/joa.12449] [Citation(s) in RCA: 297] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 12/13/2022] Open
Abstract
Morphologists have historically had to rely on destructive procedures to visualize the three‐dimensional (3‐D) anatomy of animals. More recently, however, non‐destructive techniques have come to the forefront. These include X‐ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard‐tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT‐based research is the use of chemical agents to render visible, and differentiate between, soft‐tissue structures in X‐ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine‐based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine‐based, contrast‐enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting‐edge applications of diffusible iodine‐based contrast‐enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.
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Affiliation(s)
- Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, USA
| | - Nathan J Kley
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Julia A Clarke
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Matthew W Colbert
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | | | - Donald Cerio
- Department of Biological Sciences, Ohio University, Athens, OH, USA
| | - Ian N Cost
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Philip G Cox
- Department of Archaeology, University of York and Hull York Medical School, York, UK
| | - Juan D Daza
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | | | | | - R Mark Henkelman
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - A Nele Herdina
- Department of Theoretical Biology, University of Vienna, Vienna, Austria
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Zhiheng Li
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Kristin Mahlow
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Samer Merchant
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, USA
| | - Johannes Müller
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Courtney P Orsbon
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | - Daniel J Paluh
- Department of Biology, Villanova University, Villanova, PA, USA
| | - Monte L Thies
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | - Henry P Tsai
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.,Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
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18
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Kleinteich T, Gorb SN. Frog tongue surface microstructures: functional and evolutionary patterns. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:893-903. [PMID: 27547606 PMCID: PMC4979896 DOI: 10.3762/bjnano.7.81] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 06/06/2016] [Indexed: 05/12/2023]
Abstract
Frogs (Lissamphibia: Anura) use adhesive tongues to capture fast moving, elusive prey. For this, the tongues are moved quickly and adhere instantaneously to various prey surfaces. Recently, the functional morphology of frog tongues was discussed in context of their adhesive performance. It was suggested that the interaction between the tongue surface and the mucus coating is important for generating strong pull-off forces. However, despite the general notions about its importance for a successful contact with the prey, little is known about the surface structure of frog tongues. Previous studies focused almost exclusively on species within the Ranidae and Bufonidae, neglecting the wide diversity of frogs. Here we examined the tongue surface in nine different frog species, comprising eight different taxa, i.e., the Alytidae, Bombinatoridae, Megophryidae, Hylidae, Ceratophryidae, Ranidae, Bufonidae, and Dendrobatidae. In all species examined herein, we found fungiform and filiform papillae on the tongue surface. Further, we observed a high degree of variation among tongues in different frogs. These differences can be seen in the size and shape of the papillae, in the fine-structures on the papillae, as well as in the three-dimensional organization of subsurface tissues. Notably, the fine-structures on the filiform papillae in frogs comprise hair-like protrusions (Megophryidae and Ranidae), microridges (Bufonidae and Dendrobatidae), or can be irregularly shaped or absent as observed in the remaining taxa examined herein. Some of this variation might be related to different degrees of adhesive performance and may point to differences in the spectra of prey items between frog taxa.
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Affiliation(s)
- Thomas Kleinteich
- Functional Morphology and Biomechanics, Zoology Department, Kiel University, 24118 Kiel, Germany
| | - Stanislav N Gorb
- Functional Morphology and Biomechanics, Zoology Department, Kiel University, 24118 Kiel, Germany
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