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Matsumoto R, Fujiwara SI, Evans SE. The anatomy and feeding mechanism of the Japanese giant salamander (Andrias japonicus). J Anat 2024; 244:679-707. [PMID: 38217319 PMCID: PMC11021680 DOI: 10.1111/joa.14004] [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] [Received: 11/20/2023] [Revised: 12/20/2023] [Accepted: 12/27/2023] [Indexed: 01/15/2024] Open
Abstract
The fully aquatic Japanese giant salamander (Andrias japonicus) is a member of the Cryptobranchidae, and is currently distributed in western Japan, with other members of this group restricted to China and North America. Their feeding behaviour is characterized by a form of suction feeding that includes asymmetric movements of the jaw and hyobranchial apparatus. Previous studies on the North American species, Cryptobranchus alleganiensis, have suggested that this specialized jaw movement is produced by a flexible quadrate-articular joint combined with a loosely connected lower jaw symphysis including two small fibrocartilaginous pads. However, little is known about this feeding behaviour in the Asian species, nor have the three-dimensional asymmetric jaw movements been fully investigated in any member of Cryptobranchidae. In this study, we explore the asymmetric jaw movements in A. japonicus using three methods: (1) dissection of musculoskeletal structures; (2) filming of feeding behaviour to understand in which situations asymmetric feeding is used; (3) analysis of 3D movement of jaws and skull. In the third component, fresh (from frozen) specimens of A. japonicus were manipulated to replicate asymmetric and symmetric jaw movements, with the specimens CT scanned after each step to obtain the 3D morphology of the jaws at different positions. These positions were combined and their Euler angles from resting (closed) jaw position were calculated for asymmetric or symmetric jaw positions. Our filming revealed that asymmetric jaw movements are linked to the position of the prey in relation to the snout, with the jaw closest to the prey opening asymmetrically. Moreover, this action allows the salamander to simultaneously grasp prey in one side of the mouth while ejecting water on the other side, if the first suction attempt fails. The asymmetric jaw movements are performed mainly by rotation of the mandible about its long axis, with very limited lateral jaw movements. During asymmetric and symmetric jaw movements, the posterior ends of the maxilla and quadrate move slightly. The asymmetric jaw movements are permitted by a mobile quadrate-articular joint formed by wide, round cartilages, and by two small fibrocartilage pads within the jaw symphysis that act as cushions during jaw rotation. Some of these soft tissue structures leave traces on the jaws and skull, allowing feeding mode to be reconstructed in fossil taxa. Understanding cryptobranchid asymmetric jaw movement thus requires a comprehensive assessment of not only the symphysial morphology but also that of other cranial and hyobranchial elements.
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Affiliation(s)
- Ryoko Matsumoto
- Kanagawa Prefectural Museum of Natural History, Odawara, Kanagawa, Japan
| | | | - Susan E Evans
- Department of Cell and Developmental Biology, UCL, University College London, London, UK
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2
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Schwarz D, Heiss E, Pierson TW, Konow N, Schoch RR. Using salamanders as model taxa to understand vertebrate feeding constraints during the late Devonian water-to-land transition. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220541. [PMID: 37839447 PMCID: PMC10577038 DOI: 10.1098/rstb.2022.0541] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 07/23/2023] [Indexed: 10/17/2023] Open
Abstract
The vertebrate water-to-land transition and the rise of tetrapods brought about fundamental changes for the groups undergoing these evolutionary changes (i.e. stem and early tetrapods). These groups were forced to adapt to new conditions, including the distinct physical properties of water and air, requiring fundamental changes in anatomy. Nutrition (or feeding) was one of the prime physiological processes these vertebrates had to successfully adjust to change from aquatic to terrestrial life. The basal gnathostome feeding mode involves either jaw prehension or using water flows to aid in ingestion, transportation and food orientation. Meanwhile, processing was limited primarily to simple chewing bites. However, given their comparatively massive and relatively inflexible hyobranchial system (compared to the more muscular tongue of many tetrapods), it remains fraught with speculation how stem and early tetrapods managed to feed in both media. Here, we explore ontogenetic water-to-land transitions of salamanders as functional analogues to model potential changes in the feeding behaviour of stem and early tetrapods. Our data suggest two scenarios for terrestrial feeding in stem and early tetrapods as well as the presence of complex chewing behaviours, including excursions of the jaw in more than one dimension during early developmental stages. Our results demonstrate that terrestrial feeding may have been possible before flexible tongues evolved. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.
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Affiliation(s)
- Daniel Schwarz
- Department of Palaeontology, State Museum of Natural History Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstrasse 1, 07743 Jena, Germany
| | - Egon Heiss
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstrasse 1, 07743 Jena, Germany
| | - Todd W. Pierson
- Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, Kennesaw, GA 30144, USA
| | - Nicolai Konow
- Department of Biological Sciences, University of Massachusetts Lowell, 198 Riverside Street, Lowell, MA 01854, USA
| | - Rainer R. Schoch
- Department of Palaeontology, State Museum of Natural History Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany
- Institute for Biology, Department of Palaeontology, University of Hohenheim, Wollgrasweg 23, 70599 Stuttgart, Germany
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3
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Easterling CM, Kolmann MA, O'Donnell MK. The Lesser-Known Transitions: Organismal Form and Function Across Abiotic Gradients. Integr Comp Biol 2022; 62:829-839. [PMID: 35927766 DOI: 10.1093/icb/icac133] [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: 04/01/2022] [Revised: 04/20/2022] [Accepted: 04/26/2022] [Indexed: 11/12/2022] Open
Abstract
From minute-to-minute changes, or across daily, seasonal, or geological timescales, animals are forced to navigate dynamic surroundings. Their abiotic environment is continually changing. These changes could include alterations to the substrates animals locomote on, flow dynamics of the microhabitats they feed in, or even altitudinal shifts over migration routes. The only constancy in any organism's day-to-day existence is the heterogeneity of the habitats they move through and the gradients in the physical media (e.g., air, water) they live in. We explored a broad range of organismal transitions across abiotic gradients and investigated how these organisms modify their form, function, and behavior to accommodate their surrounding media. We asked the following questions: (1) What are some challenges common to animals in changing media or moving between media? (2) What are common solutions to these recurring problems? (3) How often are these common solutions instances of either convergence or parallelism? Our symposium speakers explored these questions through critical analysis of numerous datasets spanning multiple taxa, timescales, and levels of analysis. After discussions with our speakers, we suggest that the role of physical principles (e.g., drag, gravity, buoyancy, viscosity) in constraining morphology and shaping the realized niche has been underappreciated. We recommend that investigations of these transitions and corresponding adaptations should include comparisons at multiple levels of biological organization and timescale. Relatedly, studies of organisms that undergo habitat and substrate changes over ontogeny would be worthwhile to include in comparisons. Future researchers should ideally complement lab-based morphological and kinematic studies with observational and experimental approaches in the field. Synthesis of the findings of our speakers across multiple study systems, timescales, and transitional habitats suggests that behavioral modification and exaptation of morphology play key roles in modulating novel transitions between substrates.
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Affiliation(s)
- C M Easterling
- Northwest University, Science Department, Kirkland, WA 98033
| | - M A Kolmann
- University of Michigan, Museum of Paleontology, Ann Arbor, MI 48109
| | - M K O'Donnell
- Lycoming College, Biology Department, Williamsport, PA 17701
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4
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Ishikawa K, Taguchi Y, Kobayashi R, Anzai W, Hayashi T, Tokita M. Cranial skeletogenesis of one of the largest amphibians, Andrias japonicus, provides insight into ontogenetic adaptations for feeding in salamanders. Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlab038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Skeletal development in salamanders is greatly influenced by their complex life history. Although the relationship between skull development and life history has been investigated in a variety of salamander species, few studies have compared skull development among lineages. Here, we describe the cranial skeletogenesis of the Japanese giant salamander, Andrias japonicus (family Cryptobranchidae), for the first time. To conduct interspecific comparisons, we also describe the cranial skeletogenesis of Hynobius nebulosus (Hynobiidae), Pleurodeles waltl (Salamandridae) and Ambystoma mexicanum (Ambystomatidae). Our comparative analyses reveal interspecific differences in cranial skeletogenesis, particularly in the timing of the onset of ossification, the direction of ossification (e.g. from anterior to posterior) and the ossification pattern of the hyobranchial skeleton. The early onset of jaw ossification, posterior extension of the maxilla and posterolateral inclination of the squamosal in An. japonicus might be adaptations that allow An. japonicus to gulp feed, primarily using the suction force generated by opening the mouth wide, while also supplementing that force by depressing the hyobranchial skeleton. Multivariate regression of skull shape on log10-transformed centroid size revealed that the unique skull shape of adult and subadult An. japonicus forms through hypermorphosis.
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Affiliation(s)
- Kaoru Ishikawa
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan
| | - Yuki Taguchi
- Hiroshima City Asa Zoological Park, Doubutsuen, Asa-cho, Asakita-ku, Hiroshima, Hiroshima, 731-3355, Japan
| | - Ryomei Kobayashi
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan
| | - Wataru Anzai
- Hiroshima City Asa Zoological Park, Doubutsuen, Asa-cho, Asakita-ku, Hiroshima, Hiroshima, 731-3355, Japan
| | - Toshinori Hayashi
- Amphibian Research Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Masayoshi Tokita
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan
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Schwarz D, Gorb SN, Kovalev A, Konow N, Heiss E. Flexibility of intraoral food processing in the salamandrid newt Triturus carnifex: effects of environment and prey type. J Exp Biol 2020; 223:jeb232868. [PMID: 32968002 DOI: 10.1242/jeb.232868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/09/2020] [Indexed: 11/20/2022]
Abstract
Intraoral food processing mechanisms are known for all major vertebrate groups, but the form and function of systems used to crush, grind or puncture food items can differ substantially between and within groups. Most vertebrates display flexible mechanisms of intraoral food processing with respect to different environmental conditions or food types. It has recently been shown that newts use cyclical loop-motions of the tongue to rasp prey against the palatal dentition. However, it remains unknown whether newts can adjust their food processing behavior in response to different food types or environmental conditions. Newts are interesting models for studying the functional adaptation to different conditions because of their unique and flexible lifestyle: they seasonally change between aquatic and terrestrial habitats, adapt their prey-capture mode to the respective environment, and consume diverse food types with different mechanical properties. Using X-ray high-speed recordings, anatomical investigations, behavioral analyses and mechanical property measurements, we tested the effects of the medium in which feeding occurs (water/air) and the food type (maggot, earthworm, cricket) on the processing behavior in Triturus carnifex We discovered that food processing, by contrast to prey capture, differed only slightly between aquatic and terrestrial habitats. However, newts adjusted the number of processing cycles to different prey types: while maggots were processed extensively, earthworm pieces were barely processed at all. We conclude that, in addition to food mechanical properties, sensory feedback such as smell and taste appear to induce flexible processing responses, while the medium in which feeding occurs appears to have less of an effect.
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Affiliation(s)
- Daniel Schwarz
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstraße 1, 07743 Jena, Germany
| | - Stanislav N Gorb
- Zoological Institute, Kiel University, am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Alexander Kovalev
- Zoological Institute, Kiel University, am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Nicolai Konow
- Department of Biological Sciences, University of Massachusetts Lowell., 198 Riverside Street, Lowell, MA 01854, USA
| | - Egon Heiss
- Institute of Zoology and Evolutionary Research, Friedrich Schiller University Jena, Erbertstraße 1, 07743 Jena, Germany
- Ark-Biodiversity, Willdenowstraße 6, 12203 Berlin, Germany
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6
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Deban SM, Holzman R, Müller UK. Suction Feeding by Small Organisms: Performance Limits in Larval Vertebrates and Carnivorous Plants. Integr Comp Biol 2020; 60:852-863. [PMID: 32658970 DOI: 10.1093/icb/icaa105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Suction feeding has evolved independently in two highly disparate animal and plant systems, aquatic vertebrates and carnivorous bladderworts. We review the suction performance of animal and plant suction feeders to explore biomechanical performance limits for aquatic feeders based on morphology and kinematics, in the context of current knowledge of suction feeding. While vertebrates have the greatest diversity and size range of suction feeders, bladderworts are the smallest and fastest known suction feeders. Body size has profound effects on aquatic organismal function, including suction feeding, particularly in the intermediate flow regime that tiny organisms can experience. A minority of tiny organisms suction feed, consistent with model predictions that generating effective suction flow is less energetically efficient and also requires more flow-rate specific power at small size. Although the speed of suction flows generally increases with body and gape size, some specialized tiny plant and animal predators generate suction flows greater than those of suction feeders 100 times larger. Bladderworts generate rapid flow via high-energy and high-power elastic recoil and suction feed for nutrients (relying on photosynthesis for energy). Small animals may be limited by available muscle energy and power, although mouth protrusion can offset the performance cost of not generating high suction pressure. We hypothesize that both the high energetic costs and high power requirements of generating rapid suction flow shape the biomechanics of small suction feeders, and that plants and animals have arrived at different solutions due in part to their different energy budgets.
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Affiliation(s)
- Stephen M Deban
- Department of Integrative Biology, University of South Florida, 4202 E. Fowler Ave, SCA 110, Tampa, FL 33620, USA
| | - Roi Holzman
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel.,The Inter-University for Marine Sciences in Eilat, Israel
| | - Ulrike K Müller
- Department of Biology, California State University Fresno, Fresno, CA 93740, USA
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7
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Berg O, Singh K, Hall MR, Schwaner MJ, Müller UK. Thermodynamics of the Bladderwort Feeding Strike-Suction Power from Elastic Energy Storage. Integr Comp Biol 2020; 59:1597-1608. [PMID: 31406979 DOI: 10.1093/icb/icz144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The carnivorous plant bladderwort exemplifies the use of accumulated elastic energy to power motion: respiration-driven pumps slowly load the walls of its suction traps with elastic energy (∼1 h). During a feeding strike, this energy is released suddenly to accelerate water (∼1 ms). However, due to the traps' small size and concomitant low Reynolds number, a significant fraction of the stored energy may be dissipated as viscous friction. Such losses and the mechanical reversibility of Stokes flow are thought to degrade the feeding success of other suction feeders in this size range, such as larval fish. In contrast, triggered bladderwort traps are generally successful. By mapping the energy budget of a bladderwort feeding strike, we illustrate how this smallest of suction feeders can perform like an adult fish.
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Affiliation(s)
- Otto Berg
- Department of Chemistry, California State University Fresno, Fresno, CA, USA
| | - Krizma Singh
- Department of Biology, California State University Fresno, Fresno, CA, USA
| | - Maxwell R Hall
- Department of Biology, California State University Fresno, Fresno, CA, USA
| | | | - Ulrike K Müller
- Department of Biology, California State University Fresno, Fresno, CA, USA
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8
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Suction Flows Generated by the Carnivorous Bladderwort Utricularia—Comparing Experiments with Mechanical and Mathematical Models. FLUIDS 2020. [DOI: 10.3390/fluids5010033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Suction feeding is a well-understood feeding mode among macroscopic aquatic organisms. The little we know about small suction feeders from larval fish suggests that small suction feeders are not effective. Yet bladderworts, an aquatic carnivorous plant with microscopic underwater traps, have strong suction performances despite having the same mouth size as that of fish larvae. Previous experimental studies of bladderwort suction feeding have focused on the solid mechanics of the trap door’s opening mechanism rather than the mechanics of fluid flow. As flows are difficult to study in small suction feeders due to their small size and brief event durations, we combine flow visualization on bladderwort traps with measurements on a mechanical, dynamically scaled model of a suction feeder. We find that bladderwort traps generate flows that are more similar to the inertia-dominated flows of adult fish than the viscosity-dominated flows of larval fish. Our data further suggest that axial flow transects through suction flow fields, often used in biological studies to characterize suction flows, are less diagnostic of the relative contribution of inertia versus viscosity than transverse transects.
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9
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Kane EA, Cohen HE, Hicks WR, Mahoney ER, Marshall CD. Beyond Suction-Feeding Fishes: Identifying New Approaches to Performance Integration During Prey Capture in Aquatic Vertebrates. Integr Comp Biol 2019; 59:456-472. [DOI: 10.1093/icb/icz094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Abstract
Organisms are composed of hierarchically arranged component parts that must work together to successfully achieve whole organism functions. In addition to integration among individual parts, some ecological demands require functional systems to work together in a type of inter-system performance integration. While performance can be measured by the ability to successfully accomplish ecologically relevant tasks, integration across performance traits can provide a deeper understanding of how these traits allow an organism to survive. The ability to move and the ability to consume food are essential to life, but during prey capture these two functions are typically integrated. Suction-feeding fishes have been used as a model of these interactions, but it is unclear how other ecologically relevant scenarios might reduce or change integration. To stimulate further research into these ideas, we highlight three contexts with the potential to result in changes in integration and underlying performance traits: (1) behavioral flexibility in aquatic feeding modes for capturing alternative prey types, (2) changes in the physical demands imposed by prey capture across environments, and (3) secondary adaptation for suction prey capture behaviors. These examples provide a broad scope of potential drivers of integration that are relevant to selection pressures experienced across vertebrate evolution. To demonstrate how these ideas can be applied and stimulate hypotheses, we provide observations from preliminary analyses of locally adapted populations of Trinidadian guppies (Poecilia reticulata) capturing prey using suction and biting feeding strategies and an Atlantic mudskipper (Periophthalmus barbarus) capturing prey above and below water. We also include a re-analysis of published data from two species of secondarily aquatic cetaceans, beluga whales (Delphinapterus leucas) and Pacific white-sided dolphins (Lagenorhynchus obliquidens), to examine the potential for secondary adaptation to affect integration in suction prey capture behaviors. Each of these examples support the broad importance of integration between locomotor and feeding performance but outline new ways that these relationships can be important when suction demands are reduced or altered. Future work in these areas will yield promising insights into vertebrate evolution and we hope to encourage further discussion on possible avenues of research on functional integration during prey capture.
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Affiliation(s)
- Emily A Kane
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
| | - Hannah E Cohen
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
| | - William R Hicks
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
| | - Emily R Mahoney
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
| | - Christopher D Marshall
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX, USA
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, USA
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10
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Montuelle SJ, Kane EA. Food Capture in Vertebrates: A Complex Integrative Performance of the Cranial and Postcranial Systems. FEEDING IN VERTEBRATES 2019. [DOI: 10.1007/978-3-030-13739-7_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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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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Jacobs C, Holzman R. Conserved spatio-temporal patterns of suction-feeding flows across aquatic vertebrates: a comparative flow visualization study. J Exp Biol 2018; 221:jeb.174912. [DOI: 10.1242/jeb.174912] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/28/2018] [Indexed: 11/20/2022]
Abstract
Suction feeding is a widespread prey capture strategy among aquatic vertebrates. It is almost omnipresent across fishes, and has repeatedly evolved in other aquatic vertebrates. By rapidly expanding the mouth cavity, suction-feeders generate a fluid flow outside of their mouth, drawing prey inside. Fish and other suction feeding organisms display remarkable trophic diversity, echoed in the diversity of their skull and mouth morphologies. Yet, it is unclear how variable suction flows are across species, and whether variation in suction flows supports trophic diversity. Using a high-speed flow visualization technique, we characterized the spatio-temporal patterns in the flow fields produced during feeding in 14 species of aquatic suction feeders. We found that suction-feeding hydrodynamics are highly conserved across species. Suction flows affected only a limited volume of ∼1 gape diameter away from the mouth, and peaked around the timing of maximal mouth opening. The magnitude of flow speed increased with increasing mouth diameter and, to a lesser extent, with decreasing time to peak gape opening. Other morphological, kinematic and behavioral variables played a minor role in shaping suction-feeding dynamics. We conclude that the trophic diversity within fishes, and likely other aquatic vertebrates, is not supported by a diversity of mechanisms that modify the characteristics of suction flow. Rather, we suggest that suction feeding supports such trophic diversity due to the general lack of strong trade-offs with other mechanisms that contribute to prey capture.
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Affiliation(s)
- Corrine Jacobs
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
- The Inter-University Institute for Marine Sciences, POB 469, Eilat 88103, Israel
| | - Roi Holzman
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
- The Inter-University Institute for Marine Sciences, POB 469, Eilat 88103, Israel
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13
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Stinson CM, Deban SM. Functional morphology of terrestrial prey capture in salamandrid salamanders. J Exp Biol 2017; 220:3896-3907. [DOI: 10.1242/jeb.164285] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/21/2017] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Salamanders use the hyobranchial apparatus and its associated musculature for tongue projection on land and for suction feeding in water. Hyobranchial apparatus composition and morphology vary across species, and different morphologies are better suited for feeding in aquatic versus terrestrial environments. We hypothesize that differences in hyobranchial morphology result in functional trade-offs in feeding performance. We predict that semi-aquatic and aquatic salamandrids with hyobranchial morphology suited for aquatic feeding will have lower performance, in terms of tongue-projection distance, velocity, acceleration and power, compared with terrestrial salamandrids when feeding in a terrestrial environment. We found that semi-aquatic and aquatic newts had lower velocity, acceleration and muscle-mass-specific power of tongue projection when compared with the terrestrial salamanders Chioglossa lusitanica and Salamandra salamandra. The fully aquatic newt, Paramesotriton labiatus, has a robust, heavily mineralized hyobranchial apparatus and was unable to project its tongue during terrestrial feeding, and instead exhibited suction-feeding movements better suited for aquatic feeding. Conversely, terrestrial species have slender, cartilaginous hyobranchial apparatus and enlarged tongue pads that coincided with greater tongue-projection distance, velocity, acceleration and power. Chioglossa lusitanica exhibited extreme tongue-projection performance, similar to that seen in elastically projecting plethodontid salamanders; muscle-mass-specific power of tongue projection exceeded 2200 W kg−1, more than 350 times that of the next highest performer, S. salamandra, which reached 6.3 W kg−1. These findings reveal that two fully terrestrial salamandrids have morphological specializations that yield greater tongue-projection performance compared with species that naturally feed in both aquatic and terrestrial environments.
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Affiliation(s)
- Charlotte M. Stinson
- Department of Biology, California State University, Bakersfield, Bakersfield, CA 93311, USA
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
| | - Stephen M. Deban
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
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