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Krings W, Gorb SN, Neumann C, Wägele H. Radular Tooth Coating in Members of Dendronotidae and Flabellinidae (Nudibranchia, Gastropoda, Mollusca). J Morphol 2024; 285:e21773. [PMID: 39252400 DOI: 10.1002/jmor.21773] [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: 07/09/2024] [Revised: 08/18/2024] [Accepted: 08/23/2024] [Indexed: 09/11/2024]
Abstract
Nudibranchs, with their mesmerizing diversity and ecological significance, play crucial roles in marine ecosystems. Central to their feeding prowess is the radula, a chitinous structure with diverse morphologies adapted to prey preferences and feeding strategies. This study focuses on elucidating wear coping mechanisms in radular teeth of carnivorous molluscs, employing Dendronotus lacteus (Dendronotidae) and Flabellina affinis (Flabellinidae) as model species. Both species forage on hydrozoans. Through scanning electron microscopy, confocal laser scanning microscopy, nanoindentation, and energy-dispersive X-ray spectroscopy, the biomechanical and compositional properties of their teeth were analyzed. Notably, tooth coatings, composed of calcium (Ca) or silicon (Si) and high hardness and stiffness compared to the internal tooth structure, with varying mineral contents across tooth regions and ontogenetic zones, were found. The presence of the hard and stiff tooth coatings highlight their role in enhancing wear resistance. The heterogeneities in the autofluorescence patterns related to the distribution of Ca and Si of the coatings. Overall, this study provides into the biomechanical adaptations of nudibranch radular teeth, shedding light on the intricate interplay between tooth structure, elemental composition, and ecological function in marine molluscs.
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Affiliation(s)
- Wencke Krings
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Leipzig, Germany
- Department of Electron Microscopy, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, Germany
- Department of Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Hamburg, Germany
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Charlotte Neumann
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Leipzig, Germany
- Department of Electron Microscopy, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, Germany
- Department of Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Hamburg, Germany
| | - Heike Wägele
- Department of Phylogenetics and Evolutionary Biology, Leibniz Institute for the Analysis of Biodiversity Change, Bonn, Germany
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Krings W, Gorb SN. Performance of biological food processing interfaces: Perspectives on the science of mollusc radula. Biointerphases 2024; 19:030801. [PMID: 38940493 DOI: 10.1116/6.0003672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 05/30/2024] [Indexed: 06/29/2024] Open
Abstract
The Mollusca comprises a diverse range of organisms, with the class Gastropoda alone boasting approximately 80 000 extant species. Their adaptability across various habitats is facilitated by the evolution of the radula, a key structure for food acquisition. The radula's composition and mechanical properties, including its chitinous membrane, teeth, and supporting structures, enable efficient food gathering and processing. Through adaptive tooth morphology and composition, an interplay between radular components is facilitated, which results in collective effects to withstand forces encountered during feeding and reduce structural failure, with the broad range of variations reflecting ecological niches. Furthermore, teeth consist of composite materials with sometimes high contents of iron, calcium, or silicon to reduce wear. During interaction with the food, the radula performs complex three-dimensional motions, challenging to document. Here, we provide a review on the morphology, the mechanical properties, the composition, and various other parameters that contribute to radular performance. Due to, e.g., the smallness of these structures, there are, however, limitations to radular research. However, numerical simulations and physical models tested on substrates offer avenues for further understanding radular function and performance during feeding. These studies not only advance our knowledge of molluscan biology and ecology but also provide inspirations for biomimetic design and further advances in materials engineering.
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Affiliation(s)
- Wencke Krings
- Department of Electron Microscopy, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, Hamburg 20146, Germany
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Liebigstraße 12, Leipzig 04103, Germany
- Department of Mammalogy and Paleoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, Hamburg 20146, Germany
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel 24118, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel 24118, Germany
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3
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Werth AJ, Crompton AW. Cetacean tongue mobility and function: A comparative review. J Anat 2023; 243:343-373. [PMID: 37042479 PMCID: PMC10439401 DOI: 10.1111/joa.13876] [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: 02/01/2022] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 04/13/2023] Open
Abstract
Cetaceans are atypical mammals whose tongues often depart from the typical (basal) mammalian condition in structure, mobility, and function. Their tongues are dynamic, innovative multipurpose tools that include the world's largest muscular structures. These changes reflect the evolutionary history of cetaceans' secondary adaptation to a fully aquatic environment. Cetacean tongues play no role in mastication and apparently a greatly reduced role in nursing (mainly channeling milk ingestion), two hallmarks of Mammalia. Cetacean tongues are not involved in drinking, breathing, vocalizing, and other non-feeding activities; they evidently play no or little role in taste reception. Although cetaceans do not masticate or otherwise process food, their tongues retain key roles in food ingestion, transport, securing/positioning, and swallowing, though by different means than most mammals. This is due to cetaceans' aquatic habitat, which in turn altered their anatomy (e.g., the intranarial larynx and consequent soft palate alteration). Odontocetes ingest prey via raptorial biting or tongue-generated suction. Odontocete tongues expel water and possibly uncover benthic prey via hydraulic jetting. Mysticete tongues play crucial roles driving ram, suction, or lunge ingestion for filter feeding. The uniquely flaccid rorqual tongue, not a constant volume hydrostat (as in all other mammalian tongues), invaginates into a balloon-like pouch to temporarily hold engulfed water. Mysticete tongues also create hydrodynamic flow regimes and hydraulic forces for baleen filtration, and possibly for cleaning baleen. Cetacean tongues lost or modified much of the mobility and function of generic mammal tongues, but took on noteworthy morphological changes by evolving to accomplish new tasks.
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Affiliation(s)
- Alexander J Werth
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, Virginia, USA
| | - A W Crompton
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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Ingle DN, Perez E, Porter ME, Marshall CD. Feeding without teeth: the material properties of rhamphothecae from two species of durophagous sea turtles. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221424. [PMID: 37090964 PMCID: PMC10113817 DOI: 10.1098/rsos.221424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
The feeding apparatus of sea turtles comprises cornified keratinous rhamphothecae overlaying a bony rostrum. Although keratin is less stiff than the enamel of toothed animals, certain species of sea turtles are capable of withstanding large forces when feeding on hard prey. We aimed to quantify the mineral density, water content and compressive mechanical properties of rhamphothecae from two durophagous species: loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) sea turtles. Since loggerheads theoretically produce the greater bite forces of these two species, we predicted that keratin from their rhamphothecae would have a greater mineral density and be stiffer, stronger and tougher compared with Kemp's ridley sea turtles. We found that total water weight of hydrated specimens (20%) was consistent between species. Rhamphotheca mineral density ranged between 0 and 0.069 g cm-3; loggerheads had significantly greater mineral density compared with Kemp's ridleys, for which several specimens had no mineral detected. Despite the greater mineral density in loggerheads, we found no significant difference in Young's modulus, yield strength or toughness between these species. In addition to mineral density, our findings suggest that other material components, such as sulfur, may be influencing the material properties of keratin from sea turtle rhamphothecae.
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Affiliation(s)
- Danielle N. Ingle
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77554, USA
- Gulf Center for Sea Turtle Research, Texas A&M University, College Station, TX 77843, USA
| | - Eliza Perez
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77554, USA
| | - Marianne E. Porter
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Christopher D. Marshall
- Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77554, USA
- Gulf Center for Sea Turtle Research, Texas A&M University, College Station, TX 77843, USA
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA
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Vandenberg ML, Cohen KE, Rubin RD, Goldbogen JA, Summers AP, Paig-Tran EWM, Kahane-Rapport SR. Formation of a fringe: A look inside baleen morphology using a multimodal visual approach. J Morphol 2023; 284:e21574. [PMID: 36807194 DOI: 10.1002/jmor.21574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 02/23/2023]
Abstract
Filter-feeding has been present for hundreds of millions of years, independently evolving in aquatic vertebrates' numerous times. Mysticete whales are a group of gigantic, marine filter-feeders that are defined by their fringed baleen and are divided into two groups: balaenids and rorquals. Recent studies have shown that balaenids likely feed using a self-cleaning, cross-flow filtration mechanism where food particles are collected and then swept to the esophagus for swallowing. However, it is unclear how filtering is achieved in the rorquals (Balaenopteridae). Lunging rorqual whales engulf enormous masses of both prey and water; the prey is then separated from the water through baleen plates lining the length of their upper jaw and positioned perpendicular to flow. Rorqual baleen is composed of both major (larger) and minor (smaller) keratin plates containing embedded fringe that extends into the whale's mouth, forming a filtering fringe. We used a multimodal approach, including microcomputed tomography (µCT) and scanning electron microscopy (SEM), to visualize and describe the variability in baleen anatomy across five species of rorqual whales, spanning two orders of magnitude in body length. For most morphological measurements, larger whales exhibited hypoallometry relative to body length. µCT and SEM revealed that the major and minor plates break away from the mineralized fringes at variable distances from the gums. We proposed a model for estimating the effective pore size to determine whether flow scales with body length or prey size across species. We found that pore size is likely not a proxy for prey size but instead, may reflect changes in resistance through the filter that affect fluid flow.
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Affiliation(s)
- Megan L Vandenberg
- Department of Biology, University of Washington, Seattle, Washington, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
| | - Karly E Cohen
- Department of Biology, University of Washington, Seattle, Washington, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
| | | | - Jeremy A Goldbogen
- Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Adam P Summers
- Department of Biology, University of Washington, Seattle, Washington, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
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Shore SL, Giarikos DG, Duffy LK, Edwards MR, Hirons AC. Temporal Baseline of Essesntial and Non-essential Elements Recorded in Baleen of Western Arctic Bowhead Whale (Balaena mysticetus). BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2022; 108:641-645. [PMID: 34773129 PMCID: PMC8979895 DOI: 10.1007/s00128-021-03394-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
This study established the first baseline of changing elemental concentrations in bowhead whale baleen over time (1958-1999). From previously published stable isotope data, year, season (summer or winter), and location (Beaufort or Bering/Chukchi seas) were attributed to each sample. Thirteen elements (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, Zn) in baleen from nine subsistence-harvested bowhead whales (n = 138) were detected. Al, Cu, and Fe were the highest concentrations while Cd and V were among the lowest. Our data supports absorption as the main route of exposure to environmental elements rather than biomagnification due to bowhead whales' low trophic position. A linear mixed-effects model confirmed most elements' concentrations increased with time, while location and sex were insignificant explanatory factors. These temporal fluctuations were most likely a product of environmental changes due to a warming climate and human activities.
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Affiliation(s)
- Samantha L Shore
- Department of Marine and Environmental Sciences, Halmos College of Arts and Sciences, Environmental Conservation through Leading-Edge Research (SECLER), Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL, 33004, USA
| | - Dimitrios G Giarikos
- Department of Chemistry and Physics, Halmos College of Arts and Sciences, Nova Southeastern University, 3301 College Avenue, Fort Lauderdale, FL, 33314, USA
| | - Lawrence K Duffy
- Department of Chemistry & Biochemistry, University of Alaska Fairbanks, 1930 Yukon Drive Rm. 194, Fairbanks, AK, 99775, USA
| | - Mickie R Edwards
- Department of Marine and Environmental Sciences, Halmos College of Arts and Sciences, Environmental Conservation through Leading-Edge Research (SECLER), Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL, 33004, USA
| | - Amy C Hirons
- Department of Marine and Environmental Sciences, Halmos College of Arts and Sciences, Environmental Conservation through Leading-Edge Research (SECLER), Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL, 33004, USA.
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Krings W, Kovalev A, Gorb SN. Collective effect of damage prevention in taenioglossan radular teeth is related to the ecological niche in Paludomidae (Gastropoda: Cerithioidea). Acta Biomater 2021; 135:458-472. [PMID: 34358696 DOI: 10.1016/j.actbio.2021.07.073] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/25/2021] [Accepted: 07/29/2021] [Indexed: 12/20/2022]
Abstract
The molluscan radula, a thin membrane with embedded rows of teeth, is the structure for food processing and gathering. For proper functioning, radular failures must be either avoided or reduced when interacting with the preferred food, as this might be of high significance for the individual fitness. Thus, the analysis of structural failure in radular teeth could be included in studies on trophic specializations. Here, we tested the failure of non-mineralized, chitinous radular teeth from taxa, belonging to an African paludomid species flock from Lake Tanganyika and surrounding river systems. These species are of high interest for evolutionary biologists since they represent a potential result of an adaptive radiation including trophic specialisations to distinct substrates, the food is attached to. In a biomechanical experiment a shear load was applied to tooth cusps with a force transducer connected to a motorized stage until structural failure occurred. Subsequently broken areas were measured and breaking stress was calculated. As the experiments were carried out under dry and wet conditions, the high influence of the water content on the forces, teeth were capable to resist, could be documented. Wet teeth were able to resist higher forces, because of their increased flexibility and the flexibility of the embedding membrane, which enabled them either to slip away or to gain support from adjacent teeth. This mechanism can be understood as collective effect reducing structural failure without the mineralisation with wear-minimizing elements, as described for Polyplacophora and Patellogastropoda. Since the documented mechanical behaviour of radular teeth and the maximal forces, teeth resist, can directly be related to the gastropod ecological niche, both are here identified as an adaptation to preferred feeding substrates. STATEMENT OF SIGNIFICANCE: The radula, a chitinous membrane with teeth, is the molluscan feeding structure. Here we add onto existing knowledge about the relationship between tooth's mechanical properties and species' ecology by determining the tooth failure resistance. Six paludomid species (Gastropoda) of a prominent species flock from Lake Tanganyika, foraging on distinct feeding substrates, were tested. With a force transducer wet and dry teeth were broken, revealing the high influence of water content on mechanical behaviour and force resistance of teeth. Higher forces were needed to break wet radulae due to an increased flexibility of teeth and membrane, which resulted in an interlocking or twisting of teeth. Mechanical behaviour and force resistance were both identified as trophic adaptations to feeding substrate.
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8
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Krings W, Kovalev A, Gorb SN. Influence of water content on mechanical behaviour of gastropod taenioglossan radulae. Proc Biol Sci 2021; 288:20203173. [PMID: 33653134 DOI: 10.1098/rspb.2020.3173] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
One molluscan autapomorphy is the radula, the organ used for feeding. Here, for the first time, the performance and failure of taenioglossan radular teeth were tested in a biomechanical experiment which in turn allowed building hypotheses about tooth functionalities. Shear load was applied to tooth cusps with a force transducer until structural failure occurred, the broken area was measured, and finally breaking stress was calculated. These experiments were carried out under dry and wet conditions. Our results show that certain tooth types can resist higher stresses and are rather specialised to loosen food items from a surface, whereas other teeth can only gather food particles. The experiments additionally illustrate the high influence of the water content on the resulting breaking stress. When wet teeth were tested, their ductility and ability to avoid being fractured by an obstacle increased. Their flexibility also allowed them support from teeth of adjacent tooth rows, which made the whole system less prone to failure. Our results were compared with the previous data on the mechanical properties and feeding simulations. This study provides a keystone for further comparative studies aiming at connecting diversity of radulae with their possible adaptations to the ingesta.
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Affiliation(s)
- Wencke Krings
- Department of Mammalogy and Palaeoanthropology, Center of Natural History (CeNak), Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.,Department of Functional Morphology and Biomechanics, Zoological Institute of the Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Alexander Kovalev
- Department of Functional Morphology and Biomechanics, Zoological Institute of the Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute of the Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany
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Werth AJ, Sformo TL, Lysiak NS, Rita D, George JC. Baleen turnover and gut transit in mysticete whales and its environmental implications. Polar Biol 2020. [DOI: 10.1007/s00300-020-02673-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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10
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Werth AJ, Blakeney SM, Cothren AI. Oil adsorption does not structurally or functionally alter whale baleen. ROYAL SOCIETY OPEN SCIENCE 2019; 6:182194. [PMID: 31218043 PMCID: PMC6549998 DOI: 10.1098/rsos.182194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 04/24/2019] [Indexed: 06/09/2023]
Abstract
Mysticete whales filter small prey from seawater using baleen, a unique keratinous oral tissue that grows from the palate, from which it hangs in hundreds of serial plates. Laboratory experiments testing effects of oils on material strength and flexibility, particle capture and tissue architecture of baleen from four mysticete species (bowhead, Balaena mysticetus; North Atlantic right, Eubalaena glacialis; fin, Balaenoptera physalus; humpback, Megaptera novaeangliae) indicate that baleen is hydrophilic and oleophobic, shedding rather than adsorbing oil. Oils of different weights and viscosities were tested, including six petroleum-based oils and two fish or plankton oils of common whale prey. No notable differences were found by oil type or whale species. Baleen did not adsorb oil; oil was readily rinsed from baleen by flowing water, especially from moving fringes. Microscopic examination shows minimal wrinkling or peeling of baleen's cortical keratin layers, probably due to oil repelling infiltrated water. Combined results cast doubt on fears of baleen fouling by oil; filter porosity is not appreciably affected, but oil ingestion risks remain. Particle capture studies suggest potentially greater danger to mysticetes from plastic pollution than oil.
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11
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Werth AJ, Rita D, Rosario MV, Moore MJ, Sformo TL. How do baleen whales stow their filter? A comparative biomechanical analysis of baleen bending. ACTA ACUST UNITED AC 2018; 221:jeb.189233. [PMID: 30337355 DOI: 10.1242/jeb.189233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/11/2018] [Indexed: 11/20/2022]
Abstract
Bowhead and right whale (balaenid) baleen filtering plates, longer in vertical dimension (≥3-4 m) than the closed mouth, presumably bend during gape closure. This has not been observed in live whales, even with scrutiny of video-recorded feeding sequences. To determine what happens to the baleen during gape closure, we conducted an integrative, multifactorial study including materials testing, functional (flow tank and kinematic) testing and histological examination. We measured baleen bending properties along the dorsoventral length of plates and anteroposterior location within a rack of plates via mechanical (axial bending, composite flexure, compression and tension) tests of hydrated and air-dried tissue samples from balaenid and other whale baleen. Balaenid baleen is remarkably strong yet pliable, with ductile fringes, and low stiffness and high elasticity when wet; it likely bends in the closed mouth when not used for filtration. Calculation of flexural modulus from stress/strain experiments shows that the balaenid baleen is slightly more flexible where it emerges from the gums and at its ventral terminus, but kinematic analysis indicates plates bend evenly along their whole length. Fin and humpback whale baleen has similar material properties but less flexibility, with no dorsoventral variation. The internal horn tubes have greater external and hollow luminal diameter but lower density in the lateral relative to medial baleen of bowhead and fin whales, suggesting a greater capacity for lateral bending. Baleen bending has major consequences not only for feeding morphology and energetics but also for conservation given that entanglement in fishing gear is a leading cause of whale mortality.
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Affiliation(s)
- Alexander J Werth
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA 23943, USA
| | - Diego Rita
- Department of Evolutionary Biology, Ecology, and Environmental Science, University of Barcelona, 08028 Barcelona, Spain
| | - Michael V Rosario
- Department of Ecology & Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Michael J Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Todd L Sformo
- Department of Wildlife Management, North Slope Borough, Barrow, AK 99723, USA.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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Werth AJ, Potvin J, Shadwick RE, Jensen MM, Cade DE, Goldbogen JA. Filtration area scaling and evolution in mysticetes: trophic niche partitioning and the curious cases of sei and pygmy right whales. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly121] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Alexander J Werth
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA, USA
| | - Jean Potvin
- Department of Physics, Saint Louis University, St. Louis, MO, USA
| | - Robert E Shadwick
- Department of Zoology, University of British Columbia, Vancouver, B.C., Canada
| | - Megan M Jensen
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - David E Cade
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Jeremy A Goldbogen
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
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13
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Jensen MM, Saladrigas AH, Goldbogen JA. Comparative Three-Dimensional Morphology of Baleen: Cross-Sectional Profiles and Volume Measurements Using CT Images. Anat Rec (Hoboken) 2018; 300:1942-1952. [PMID: 28971628 PMCID: PMC5656919 DOI: 10.1002/ar.23648] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 06/14/2017] [Accepted: 06/17/2017] [Indexed: 12/29/2022]
Abstract
Baleen whales are obligate filter feeders, straining prey‐laden seawater through racks of keratinized baleen plates. Despite the importance of baleen to the ecology and natural history of these animals, relatively little work has been done on baleen morphology, particularly with regard to the three‐dimensional morphology and structure of baleen. We used computed tomography (CT) scanning to take 3D images of six baleen specimens representing five species, including three complete racks. With these images, we described the three‐dimensional shape of the baleen plates using cross‐sectional profiles from within the gum tissue to the tip of the plates. We also measured the percentage of each specimen that was composed of either keratinized plate material or was void space between baleen plates, and thus available for seawater flow. Baleen plates have a complex three‐dimensional structure with curvature that varies across the anterior‐posterior, proximal‐distal, and medial‐lateral (lingual‐labial) axes. These curvatures also vary with location along the baleen rack, and between species. Cross‐sectional profiles resemble backwards‐facing airfoils, and some specimens display S‐shaped, or reflexed, camber. Within a baleen specimen, the intra‐baleen void volume correlates with the average bristle diameter for a species, suggesting that essentially, thinner plates (with more space between them for flow) have thinner bristles. Both plate curvature and the relative proportions of plate and void volumes are likely to have implications for the mechanics of mysticete filtration, and future studies are needed to determine the particular functions of these morphological characters. Anat Rec, 300:1942–1952, 2017. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists
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Affiliation(s)
- Megan M Jensen
- Hopkins Marine Station of Stanford University, Pacific Grove, California, 93950
| | - Amalia H Saladrigas
- Hopkins Marine Station of Stanford University, Pacific Grove, California, 93950
| | - Jeremy A Goldbogen
- Hopkins Marine Station of Stanford University, Pacific Grove, California, 93950
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14
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Andriotis OG, Desissaire S, Thurner PJ. Collagen Fibrils: Nature's Highly Tunable Nonlinear Springs. ACS NANO 2018; 12:3671-3680. [PMID: 29529373 DOI: 10.1021/acsnano.8b00837] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Tissue hydration is well known to influence tissue mechanics and can be tuned via osmotic pressure. Collagen fibrils are nature's nanoscale building blocks to achieve biomechanical function in a broad range of biological tissues and across many species. Intrafibrillar covalent cross-links have long been thought to play a pivotal role in collagen fibril elasticity, but predominantly at large, far from physiological, strains. Performing nanotensile experiments of collagen fibrils at varying hydration levels by adjusting osmotic pressure in situ during atomic force microscopy experiments, we show the power the intrafibrillar noncovalent interactions have for defining collagen fibril tensile elasticity at low fibril strains. Nanomechanical tensile tests reveal that osmotic pressure increases collagen fibril stiffness up to 24-fold in transverse (nanoindentation) and up to 6-fold in the longitudinal direction (tension), compared to physiological saline in a reversible fashion. We attribute the stiffening to the density and strength of weak intermolecular forces tuned by hydration and hence collagen packing density. This reversible mechanism may be employed by cells to alter their mechanical microenvironment in a reversible manner. The mechanism could also be translated to tissue engineering approaches for customizing scaffold mechanics in spatially resolved fashion, and it may help explain local mechanical changes during development of diseases and inflammation.
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Affiliation(s)
- Orestis G Andriotis
- Institute of Lightweight Design and Structural Biomechanics , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
| | - Sylvia Desissaire
- Institute of Lightweight Design and Structural Biomechanics , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
| | - Philipp J Thurner
- Institute of Lightweight Design and Structural Biomechanics , Vienna University of Technology , Getreidemarkt 9 , 1060 Vienna , Austria
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15
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Werth AJ, Ito H. Sling, Scoop, and Squirter: Anatomical Features Facilitating Prey Transport, Processing, and Swallowing in Rorqual Whales (Mammalia: Balaenopteridae). Anat Rec (Hoboken) 2017; 300:2070-2086. [DOI: 10.1002/ar.23606] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/15/2017] [Accepted: 01/28/2017] [Indexed: 12/31/2022]
Affiliation(s)
| | - Haruka Ito
- National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency; Yokohama Kanagawa 236-8648 Japan
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