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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] [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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Ward P, Barord GJ, Schauer A, Veloso J. Comparative Trophic Levels of Phragmocone-Bearing Cephalopods (Nautiloids, Ammonoids, and Sepiids). Integr Comp Biol 2023; 63:1285-1297. [PMID: 37994658 DOI: 10.1093/icb/icad125] [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: 04/21/2023] [Revised: 11/06/2023] [Accepted: 11/09/2023] [Indexed: 11/24/2023] Open
Abstract
Cephalopods are among many marine animals that through some combination of habit and/or habitat have proven difficult to study, especially understanding their trophic positions in marine communities. Stable isotope analyses have provided powerful tools for discovering quantitative aspects about the ecology and food sources of many cephalopod species. Here, we present new gut content and isotopic data (carbon and nitrogen isotopes) from phragmocone-bearing cephalopods (both ectocochleates, as well as those with internal, hard part buoyancy maintenance apparatuses). To this, we also include observations from baited remote underwater video systems to describe feeding habits and potential prey types to correlate with gut contents analyses. These data come from extant Allonautilus, Nautilus, and Sepia species, as well as from extinct nautiloids and ammonites. Extant nautiloids occupy a different isotopic niche than all other cephalopod groups where such data have been published to date. We conclude that these species are obligate scavengers rather than predators on any living species in their environments. Extant Nautilus and Allonautilus also demonstrate different patterns of functional allometry of nitrogen isotope values over ontogeny than do most other cephalopods (or animals in general), by showing decreasing nitrogen isotope levels during ontogeny. This pattern is shown to be different in Sepia and the yet small number of ammonite cephalopods studied to date, supporting the increasingly accepted view that ammonites were far closer to coleoids in basic biology than nautiloids. Overall, phragmocone-bearing cephalopods appear fundamentally different ecologically than cephalopods without this kind of buoyancy system. Of these groups, nautiloids appear to live a low-energy existence that allows them to subsist on energy-poor food sources, such as crustacean molts, as well as being able to scavenge in low oxygen basins where rare food falls, such as dead fish, remain unobtainable by most other animals.
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Affiliation(s)
- Peter Ward
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Gregory J Barord
- Department of Marine Sciences, Central Campus, Des Moines, IA, 50309, USA
| | - Andrew Schauer
- Department of Earth and Space Sciences, University of Washington, Seattle, 98195 WA, USA
| | - Job Veloso
- Department of Biology, University of Washington, Seattle, WA 98195, USA
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Murphy KJ, Pecl GT, Everett JD, Heneghan RF, Richards SA, Richardson AJ, Semmens JM, Blanchard JL. Improving the biological realism of predator-prey size relationships in food web models alters ecosystem dynamics. Biol Lett 2023; 19:20230142. [PMID: 37875159 PMCID: PMC10597676 DOI: 10.1098/rsbl.2023.0142] [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: 03/24/2023] [Accepted: 10/02/2023] [Indexed: 10/26/2023] Open
Abstract
Body-size relationships between predators and prey exhibit remarkable diversity. However, the assumption that predators typically consume proportionally smaller prey often underlies size-dependent predation in ecosystem models. In reality, some animals can consume larger prey or exhibit limited changes in prey size as they grow larger themselves. These distinct predator-prey size relationships challenge the conventional assumptions of traditional size-based models. Cephalopods, with their diverse feeding behaviours and life histories, offer an excellent case study to investigate the impact of greater biological realism in predator-prey size relationships on energy flow within a size-structured ecosystem model. By categorizing cephalopods into high and low-activity groups, in line with empirically derived, distinct predator-prey size relationships, we found that incorporating greater biological realism in size-based feeding reduced ecosystem biomass and production, while simultaneously increasing biomass stability and turnover. Our results have broad implications for ecosystem modelling, since distinct predator-prey size relationships extend beyond cephalopods, encompassing a wide array of major taxonomic groups from filter-feeding fishes to baleen whales. Incorporating a diversity of size-based feeding in food web models can enhance their ecological and predictive accuracy when studying ecosystem dynamics.
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Affiliation(s)
- Kieran J. Murphy
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
- The Australian Centre for Excellence in Antarctic Science, University of Tasmania, Hobart, Australia
| | - Gretta T. Pecl
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Jason D. Everett
- School of the Environment, The University of Queensland, St Lucia, Australia
- Centre for Marine Science and Innovation, University of New South Wales, Sydney, Australia
- CSIRO Environment, St Lucia, Australia
| | - Ryan F. Heneghan
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Petrie, Australia
| | - Shane A. Richards
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Anthony J. Richardson
- School of the Environment, The University of Queensland, St Lucia, Australia
- CSIRO Environment, St Lucia, Australia
| | - Jayson M. Semmens
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Julia L. Blanchard
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
- The Australian Centre for Excellence in Antarctic Science, University of Tasmania, Hobart, Australia
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Fernández-Álvarez FÁ, Taite M, Vecchione M, Villanueva R, Allcock AL. A phylogenomic look into the systematics of oceanic squids (order Oegopsida). Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlab069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Abstract
Oceanic squids of the order Oegopsida are ecologically and economically important members of the pelagic environment. They are the most diverse group of cephalopods, with 24 families that are divergent morphologically. Despite their importance, knowledge of phylogenetic relationships among oegopsids is less than that among neritic cephalopods. Here, we provide the complete mitogenomes and the nuclear 18S and 28S ribosomal genes for 35 selected oceanic squids, which were generated using genome skimming. We performed maximum likelihood and Bayesian inference analyses that included 21 of the 24 oegopsid families. In our analyses, the architeuthid, chiroteuthid and enoploteuthid family groups, which have been proposed previously based on morphological and natural history characteristics, were retrieved as monophyletic. The morphologically divergent Cranchiidae formed a well-supported clade with families Ommastrephidae and Thysanoteuthidae, with a unique mitochondrial gene order. The family Lycoteuthidae was revealed as paraphyletic and contained Pyroteuthidae. Thus, the two lycoteuthid subfamilies are herein elevated to family level, increasing the number of oegopsid squid families to 25. In order to describe the diversity and evolutionary trends of oegopsid squids accurately, the superfamilies Architeuthoidea, Chiroteuthoidea, Cranchioidea and Enoploteuthoidea are resurrected from the literature, and the superfamilies Cycloteuthoidea, Octopoteuthoidea and Pholidoteuthoidea are proposed. The phylogenetic positions of Gonatidae, Histioteuthidae and Onychoteuthidae were not stable in our phylogenetic analyses and are not assigned to a superfamily. This study supports the utility of genome skimming to solve the phylogenetic relationships of oceanic squids.
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Affiliation(s)
| | - Morag Taite
- Ryan Institute and School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, UK
| | - Michael Vecchione
- NOAA/NMFS National Systematics Laboratory, National Museum of Natural History, Washington, DC, USA
| | - Roger Villanueva
- Institut de Ciències del Mar (CSIC), Passeig Marítim 37–49, E-08003 Barcelona, Spain
| | - A Louise Allcock
- Ryan Institute and School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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