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Hackethal S, Schulz-Kornas E, Gorb SN, Krings W. Wear patterns of radular teeth in Loligo vulgaris (Cephalopoda; Mollusca) are related to their structure and mechanical properties. Interface Focus 2024; 14:20230082. [PMID: 38618237 PMCID: PMC11008966 DOI: 10.1098/rsfs.2023.0082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 03/05/2024] [Indexed: 04/16/2024] Open
Abstract
Radular teeth have to cope with wear, when interacting with ingesta. In some molluscan taxa, wear-coping mechanisms, related to the incorporation of high contents of iron or silica, have been previously determined. For most species, particularly for those which possess radulae without such incorporations, wear-coping mechanisms are understudied. In the present study, we documented and characterized the wear on radular teeth in the model species Loligo vulgaris (Cephalopoda). By applying a range of methods, the elementary composition and mechanical properties of the teeth were described, to gain insight into mechanisms for coping with abrasion. It was found that the tooth regions that are prone to wear are harder and stiffer. Additionally, the surfaces interacting with the ingesta possessed a thin coating with high contents of silicon, probably reducing abrasion. The here presented data may serve as an example of systematic study of radular wear, in order to understand the relationship between the structure of radular teeth and their properties.
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Affiliation(s)
- Svenja Hackethal
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Liebigstraße 12, 04103 Leipzig, Germany
- Department of Mammalogy and Paleoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
- Department of Electron Microscopy, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
| | - Ellen Schulz-Kornas
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Liebigstraße 12, 04103 Leipzig, Germany
- Department of Mammalogy and Paleoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146 Hamburg, 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
| | - Wencke Krings
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Liebigstraße 12, 04103 Leipzig, Germany
- Department of Mammalogy and Paleoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146 Hamburg, 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 Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1–9, 24118 Kiel, Germany
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Herbert GS, Hill SA, Pio MJ, Carney R, Carlson A, Newham E, Bright JA. Three-dimensional visualization of predatory gastropod feeding teeth with synchrotron scanning. J Morphol 2023; 284:e21633. [PMID: 37708504 DOI: 10.1002/jmor.21633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 07/12/2023] [Accepted: 08/03/2023] [Indexed: 09/16/2023]
Abstract
Several families of neogastropod mollusks independently evolved the ability to drill through mineralized prey skeletons using their own mineralized feeding teeth, sometimes with shell-softening chemical agents produced by an organ in the foot. Teeth with more durable tooth shapes should extend their use and improve predator performance, but past studies have described only the cusped-side of teeth, mostly overlooking morphologies related to functional interactions between teeth. Here, we describe the three-dimensional morphology of the central drilling tooth (rachidian) from four species of the neogastropod family Muricidae using synchrotron tomographic microscopy and assemble a three-dimensional model of a multitooth series in drilling position for two of them to investigate their dynamic form. We find two new types of articulating surfaces, including a saddle joint at either end of the rachidian and a large tongue-and-groove joint in the center. The latter has a shape that maximizes contact surface area between teeth as they rotate away from each other during drilling. Articulating joints have not been described in Neogastropod radula previously, but they are consistent with an earlier hypothesis that impact forces on individual teeth during predatory drilling are dispersed by tooth-tooth interactions.
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Affiliation(s)
- Gregory S Herbert
- School of Geosciences, University of South Florida, Tampa, Florida, USA
| | - Stephen A Hill
- School of Geosciences, University of South Florida, Tampa, Florida, USA
| | - Maria Jose Pio
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, Argentina
| | - Ryan Carney
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Amber Carlson
- School of Geosciences, University of South Florida, Tampa, Florida, USA
| | - Elis Newham
- School of Engineering and Materials Sciences, Queen Mary University of London, London, UK
- Section Palaeontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Jen A Bright
- School of Geosciences, University of South Florida, Tampa, Florida, USA
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Krings W, Neumann C, Gorb SN, Koehnsen A, Wägele H. Elemental composition and material properties of radular teeth in the heterobranch snail Gastropteron rubrum (Mollusca, Gastropoda, Cephalaspidea) foraging on hard organisms. Ecol Evol 2023; 13:e10332. [PMID: 37589038 PMCID: PMC10425275 DOI: 10.1002/ece3.10332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/19/2023] [Accepted: 07/05/2023] [Indexed: 08/18/2023] Open
Abstract
The molluscan feeding structure is the radula, a chitinous membrane with teeth, which are highly adapted to the food and the substrate to which the food is attached. In Polyplacophora and Patellogastropoda, the handling of hard ingesta can be facilitated by high content of chemical compounds containing Fe or Si in the tooth cusps. Other taxa, however, possess teeth that are less mineralized, even though animals have to avoid structural failure or high wear during feeding as well. Here, we investigated the gastropod Gastropteron rubrum, feeding on hard Foraminifera, diatoms and Porifera. Tooth morphologies and wear were documented by scanning electron microscopy and their mechanical properties were tested by nanoindentation. We determined that gradients of hard- and stiffness run along each tooth, decreasing from cusp to basis. We also found that inner lateral teeth were harder and stiffer than the outer ones. These findings allowed us to propose hypotheses about the radula-ingesta interaction. In search for the origins of the gradients, teeth were visualized using confocal laser scanning microscopy, to determine the degree of tanning, and analyzed with energy-dispersive X-ray spectroscopy, to test the elemental composition. We found that the mechanical gradients did not have their origins in the elemental content, as the teeth did not contain high proportions of metals or other minerals. This indicates that their origin might be the degree of tanning. However, in the tooth surfaces that interact with the ingesta high Si and Ca contents were determined, which is likely an adaptation to reduce wear.
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Affiliation(s)
- Wencke Krings
- Department of Electron Microscopy, Institute of Cell and Systems Biology of AnimalsUniversität HamburgHamburgGermany
- Department of Cariology, Endodontology and PeriodontologyUniversität LeipzigLeipzigGermany
- Department of Mammalogy and PalaeoanthropologyLeibniz Institute for the Analysis of Biodiversity ChangeHamburgGermany
- Department of Functional Morphology and Biomechanics, Zoological InstituteChristian‐Albrechts‐Universität zu KielKielGermany
| | - Charlotte Neumann
- Department of Cariology, Endodontology and PeriodontologyUniversität LeipzigLeipzigGermany
- Department of Mammalogy and PalaeoanthropologyLeibniz Institute for the Analysis of Biodiversity ChangeHamburgGermany
| | - Stanislav N. Gorb
- Department of Functional Morphology and Biomechanics, Zoological InstituteChristian‐Albrechts‐Universität zu KielKielGermany
| | - Alexander Koehnsen
- Department of Electron Microscopy, Institute of Cell and Systems Biology of AnimalsUniversität HamburgHamburgGermany
- Department of Cariology, Endodontology and PeriodontologyUniversität LeipzigLeipzigGermany
| | - Heike Wägele
- Department of Phylogenetics and Evolutionary BiologyLeibniz Institute for the Analysis of Biodiversity ChangeBonnGermany
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Brütt J, Gorb SN, Krings W. The ontogeny of elements: distinct ontogenetic patterns in the radular tooth mineralization of gastropods. Sci Nat 2022; 109:58. [DOI: 10.1007/s00114-022-01829-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 09/18/2022] [Accepted: 11/18/2022] [Indexed: 12/03/2022]
Abstract
Abstract The molluscan phylum is characterized by the radula, used for the gathering and processing of food. This structure can consist of a chitinous membrane with embedded rows of teeth, which show structural, chemical, and biomechanical adaptations to the preferred ingesta. With regard to the chemical composition of teeth, some taxa (Polyplacophora and Patellogastropoda) were extensively studied, and high proportions of incorporated iron, calcium, and silicon were previously reported. However, outside these two groups, there is an immense lack of knowledge about the elemental composition of radular teeth. The here presented work aims at shedding some light on the radular composition by performing energy-dispersive X-ray spectroscopy (EDX) on six non-patelliform gastropod species (Anentome helena, Cornu aspersum, Lavigeria nassa, Littorina littorea, Reymondia horei, and Vittina turrita), with the focus on the ontogeny of the elemental composition. Proportions of elements, which are not part of chitin and other purely organic molecules, were documented for overall 1027 individual teeth of all ontogenetic radular stages, i.e., for the building zone, the maturation zone, and the working zone. We detected that the proportions of these elements increased from the building to the maturation zone. However, from the maturation to the working zone, two general trends are visible: either the proportions of the elements increased or decreased. The latter trend could potentially be explained by the acidic pH of the gastropod saliva, which awaits further investigations.
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Krings W, Matsumura Y, Brütt JO, Gorb SN. Material gradients in gastropod radulae and their biomechanical significance: a combined approach on the paludomid Lavigeria grandis. Naturwissenschaften 2022; 109:52. [PMID: 36322292 PMCID: PMC9630255 DOI: 10.1007/s00114-022-01822-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/17/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
Abstract
The radula, a chitinous membrane spiked with teeth, is the molluscan autapomorphy for the gathering and processing of food. The teeth, as actual interfaces between the organism and the ingesta, act as load transmitting regions and have to withstand high stresses during foraging — without structural failure or high degrees of wear. Mechanisms contributing to this were studied previously in paludomid gastropods from Lake Tanganyika. For some species, gradients in hardness and Young’s modulus along the teeth were detected, enabling the bending and relying of teeth onto the next row, distributing the stresses more equally. The here presented study on one of them — Lavigeria grandis — aims at shedding light on the origin of these functional gradients. The mechanical properties were identified by nanoindentation technique and compared to the elemental composition, determined by elemental dispersive X-ray spectroscopy (EDX, EDS). This was done for the complete radular (mature and immature tooth rows), resulting in overall 236 EDX and 700 nanoindentation measurements. Even though teeth showed regional differences in elemental composition, we could not correlate the mechanical gradients with the elemental proportions. By applying confocal laser scanning microscopy (CLSM), we were finally able to relate the mechanical properties with the degree of tanning. CLSM is a common technique used on arthropod cuticle, but was never applied on radular teeth before. In general, we found that nanoindentation and CLSM techniques complement one another, as for example, CLSM is capable of revealing heterogeneities in material or micro-gradients, which leads to a better understanding of the functionalities of biological materials and structures.
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Affiliation(s)
- Wencke Krings
- Department of Behavioral Biology, 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, Zoologisches Institut, Christian-Albrechts-Universität Zu Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
| | - Yoko Matsumura
- Department of Functional Morphology and Biomechanics, Zoologisches Institut, Christian-Albrechts-Universität Zu Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
- Department of General and Systematic Zoology, Zoological Institute and Museum, Universität Greifswald, Loitzer Str. 26, 17489, Greifswald, Germany
| | - Jan-Ole Brütt
- Department of Behavioral Biology, 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
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoologisches Institut, Christian-Albrechts-Universität Zu Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
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Krings W, Brütt JO, Gorb SN. Micro-cracks and micro-fractures reveal radular tooth architecture and its functional significance in the paludomid gastropod Lavigeria grandis. Philos Trans A Math Phys Eng Sci 2022; 380:20210335. [PMID: 35909353 DOI: 10.1098/rsta.2021.0335] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
Most molluscan taxa forage with their radula, a chitinous membrane with embedded teeth. The teeth are the actual interfaces between the animal and its ingesta and serve as load-transmitting regions. During foraging, these structures have to withstand high stresses without structural failure and without a high degree of wear. Mechanisms contributing to this failure- and wear-resistance were well studied in the heavily mineralized teeth of Polyplacophora and Patellogastropoda, but for the rather chitinous teeth of non-limpet snails, we are confronted with a large gap in data. The work presented here on the paludomid gastropod Lavigeria grandis aims to shed some light on radular tooth composition and its contribution to failure- and wear-prevention in this type of radula. The teeth were fractured and the micro-cracks studied in detail by scanning electron microscopy, revealing layers within the teeth. Two layers of distinct fibre densities and orientations were detected, covered by a thin layer containing high proportions of calcium and silicon, as determined by elemental dispersive X-ray spectroscopy. Our results clearly demonstrate the presence of failure- and wear-prevention mechanisms in snail radulae without the involvement of heavy mineralization-rendering this an example of a highly functional biological lightweight structure. This article is part of the theme issue 'Nanocracks in nature and industry'.
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Affiliation(s)
- Wencke Krings
- Department of Behavioral Biology, 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 9, 24118 Kiel, Germany
| | - Jan-Ole Brütt
- Department of Behavioral Biology, 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
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany
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Krings W, Brütt JO, Gorb SN. Ontogeny of the elemental composition and the biomechanics of radular teeth in the chiton Lepidochitona cinerea. Front Zool 2022; 19:19. [PMID: 35690761 PMCID: PMC9188181 DOI: 10.1186/s12983-022-00465-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 06/05/2022] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND The radula, a chitinous membrane with embedded teeth, is one important molluscan autapomorphy. In some taxa (Polyplacophora and Patellogastropoda) one tooth type (the dominant lateral tooth) was studied intensively in the last decades with regard to its mechanical properties, chemical and structural composition, and the relationship between these parameters. As the dominant lateral tooth is probably one of the best studied biological materials, it is surprising, that data on elements and mechanical properties of the other tooth types, present on a chiton radula, is lacking. RESULTS We provide data on the elemental distribution and mechanical properties (hardness and elasticity, i.e. Young's modulus) of all teeth from the Polyplacophora Lepidochitona cinerea (Linnaeus, 1767) [Chitonidae: Ischnochitonidae]. The ontogeny of elements, studied by energy-dispersive X-ray spectroscopy, and of the mechanical properties, determined by nanoindentation, was analysed in every individual tooth type. Additionally, we performed breaking stress experiments with teeth under dry and wet condition, highlighting the high influence of the water content on the mechanical behaviour of the radula. We thereby could determine the forces and stresses, teeth can resist, which were previously not studied in representatives of Polyplacophora. Overall, we were able to relate the mineral (iron, calcium) content with the mechanical parameters (hardness and Young's modulus) and the breaking force and stress in every tooth type. This led to a better understanding of the relationship between structure, material, and function in radular teeth. Further, we aimed at determining the role of calcium for the mechanical behaviour of the teeth: we decalcified radulae by ethylene diamine tetra acetic acid and performed afterwards elemental analyses, breaking stress experiments, and nanoindentation. Among other things, we detected that wet and decalcified radular teeth could resist highest forces, since teeth have a higher range of bending motion leading to a higher capability of teeth to gain mechanical support from the adjacent tooth row. This indicates, that the tooth material is the result of a compromise between failure reduction and the ability to transfer forces onto the ingesta. CONCLUSION We present novel data on the elemental composition, mechanical properties, and the mechanical behaviour of chiton teeth, which allows conclusions about tooth function. We could also relate the parameters mentioned, which contributes to our understanding on the origins of mechanical property gradients and the processes reducing structural failure in radular teeth. Additionally, we add more evidence, that the elemental composition of radular is probably species-specific and could be used as taxonomic character.
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Affiliation(s)
- Wencke Krings
- Department of Behavioral Biology, 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 9, 24118, Kiel, Germany.
| | - Jan-Ole Brütt
- Department of Behavioral Biology, 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
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 9, 24118, Kiel, Germany
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Krings W, Marcé-Nogué J, Gorb SN. Finite element analysis relating shape, material properties, and dimensions of taenioglossan radular teeth with trophic specialisations in Paludomidae (Gastropoda). Sci Rep 2021; 11:22775. [PMID: 34815469 DOI: 10.1038/s41598-021-02102-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 11/10/2021] [Indexed: 01/18/2023] Open
Abstract
The radula, a chitinous membrane with embedded tooth rows, is the molluscan autapomorphy for feeding. The morphologies, arrangements and mechanical properties of teeth can vary between taxa, which is usually interpreted as adaptation to food. In previous studies, we proposed about trophic and other functional specialisations in taenioglossan radulae from species of African paludomid gastropods. These were based on the analysis of shape, material properties, force-resistance, and the mechanical behaviour of teeth, when interacting with an obstacle. The latter was previously simulated for one species (Spekia zonata) by the finite-element-analysis (FEA) and, for more species, observed in experiments. In the here presented work we test the previous hypotheses by applying the FEA on 3D modelled radulae, with incorporated material properties, from three additional paludomid species. These species forage either on algae attached to rocks (Lavigeria grandis), covering sand (Cleopatra johnstoni), or attached to plant surface and covering sand (Bridouxia grandidieriana). Since the analysed radulae vary greatly in their general size (e.g. width) and size of teeth between species, we additionally aimed at relating the simulated stress and strain distributions with the tooth sizes by altering the force/volume. For this purpose, we also included S. zonata again in the present study. Our FEA results show that smaller radulae are more affected by stress and strain than larger ones, when each tooth is loaded with the same force. However, the results are not fully in congruence with results from the previous breaking stress experiments, indicating that besides the parameter size, more mechanisms leading to reduced stress/strain must be present in radulae.
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