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Griesshaber E, Checa AG, Salas C, Hoffmann R, Yin X, Neuser R, Rupp U, Schmahl WW. Biological light-weight materials: The endoskeletons of cephalopod mollusks. J Struct Biol 2023; 215:107988. [PMID: 37364762 DOI: 10.1016/j.jsb.2023.107988] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 06/06/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Structural biological hard tissues fulfill diverse tasks: protection, defence, locomotion, structural support, reinforcement, buoyancy. The cephalopod mollusk Spirula spirula has a planspiral, endogastrically coiled, chambered, endoskeleton consisting of the main elements: shell-wall, septum, adapical-ridge, siphuncular-tube. The cephalopod mollusk Sepia officinalis has an oval, flattened, layered-cellular endoskeleton, formed of the main elements: dorsal-shield, wall/pillar, septum, siphuncular-zone. Both endoskeletons are light-weight buoyancy devices that enable transit through marine environments: vertical (S. spirula), horizontal (S. officinalis). Each skeletal element of the phragmocones has a specific morphology, component structure and organization. The conjunction of the different structural and compositional characteristics renders the evolved nature of the endoskeletons and facilitates for Spirula frequent migration from deep to shallow water and for Sepia coverage over large horizontal distances, without damage of the buoyancy device. Based on Electron-Backscatter-Diffraction (EBSD) measurements and TEM, FE-SEM, laser-confocal-microscopy imaging we highlight for each skeletal element of the endoskeleton its specific mineral/biopolymer hybrid nature and constituent arrangement. We demonstrate that a variety of crystal morphologies and biopolymer assemblies are needed for enabling the endoskeleton to act as a buoyancy device. We show that all organic components of the endoskeletons have the structure of cholesteric-liquid-crystals and indicate which feature of the skeletal element yields the necessary mechanical property to enable the endoskeleton to fulfill its function. We juxtapose structural, microstructural, texture characteristics and benefits of coiled and planar endoskeletons and discuss how morphometry tunes structural biomaterial function. Both mollusks use their endoskeleton for buoyancy regulation, live and move, however, in distinct marine environments.
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Affiliation(s)
- Erika Griesshaber
- Department fur Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Antonio G Checa
- Departamento de Estratigrafía y Paleontología, Universidad de Granada, 18071 Granada, Spain; Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, 18100 Armilla, Spain
| | - Carmen Salas
- Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071-Málaga, Spain
| | - René Hoffmann
- Institute of Geology, Mineralogy, and Geophysics, Department of Earth Sciences, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum, Germany
| | - Xiaofei Yin
- Department fur Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Rolf Neuser
- Institute of Geology, Mineralogy, and Geophysics, Department of Earth Sciences, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum, Germany
| | - U Rupp
- Zentrale Einrichtung Elektronenmikroskopie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Wolfgang W Schmahl
- Department fur Geo- und Umweltwissenschaften, Ludwig-Maximilians-Universität München, Munich, Germany
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Lemanis R, Zlotnikov I. Fractal-like geometry as an evolutionary response to predation? Sci Adv 2023; 9:eadh0480. [PMID: 37494450 PMCID: PMC10371019 DOI: 10.1126/sciadv.adh0480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/26/2023] [Indexed: 07/28/2023]
Abstract
Fractal-like, intricate morphologies are known to exhibit beneficial mechanical behavior in various engineering and technological domains. The evolution of fractal-like, internal walls of ammonoid cephalopod shells represent one of the most clear evolutionary trends toward complexity in biology, but the driver behind their iterative evolution has remained unanswered since the first hypotheses introduced in the early 1800s. We show a clear correlation between the fractal-like morphology and structural stability. Using linear and nonlinear computational mechanical simulations, we demonstrate that the increase in the complexity of septal geometry leads to a substantial increase in the mechanical stability of the entire shell. We hypothesize that the observed tendency is a driving force toward the evolution of the higher complexity of ammonoid septa, providing the animals with superior structural support and protection against predation. Resolving the adaptational value of this unique trait is vital to fully comprehend the intricate evolutionary trends between morphology, ecological shifts, and mass extinctions through Earth's history.
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Affiliation(s)
- Robert Lemanis
- />BCUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden 01307, Germany
| | - Igor Zlotnikov
- />BCUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden 01307, Germany
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Hebdon N, Polly PD, Peterman DJ, Ritterbush KA. Detecting Mismatch in Functional Narratives of Animal Morphology: a Test Case With Fossils. Integr Comp Biol 2022; 62:icac034. [PMID: 35660875 DOI: 10.1093/icb/icac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A boom in technological advancements over the last two decades has driven a surge in both the diversity and power of analytical tools available to biomechanical and functional morphology research. However, in order to adequately investigate each of these dense datasets, one must often consider only one functional narrative at a time. There is more to each organism than any one of these form-function relationships. Joint performance landscapes determined by maximum likelihood are a valuable tool that can be used to synthesize our understanding of these multiple functional hypotheses to further explore an organism's ecology. We present an example framework for applying these tools to such a problem using the morphological transition of ammonoids from the Middle Triassic to the Early Jurassic. Across this time interval, morphospace occupation shifts from a broad occupation across Westermann Morphospace to a dense occupation of a region emphasizing an exposed umbilicus and modest frontal profile. The hydrodynamic capacities and limitations of the shell have seen intense scrutiny as a likely explanation of this transition. However, conflicting interpretations of hydrodynamic performance remain despite this scrutiny, with scant offerings of alternative explanations. Our analysis finds that hydrodynamic measures of performance do little to explain the shift in morphological occupation, highlighting a need for a more robust investigation of alternative functional hypotheses that are often intellectually set aside. With this we show a framework for consolidating the current understanding of the form-function relationships in an organism, and assess when they are insufficiently characterizing the dynamics those data are being used to explain. We aim to encourage the broader adoption of this framework and these ideas as a foundation to bring the field close to comprehensive synthesis and reconstruction of organisms.
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Affiliation(s)
- Nicholas Hebdon
- Dept. of Biological Sciences, Chapman University, Keck Center, 450 North Center Street, Orange, CA, 92866
| | - P David Polly
- Departments of Earth & Atmospheric Science, Biology, and Anthropology, Indiana University, Bloomington, IN, 47405, USA
| | - David Joseph Peterman
- Dept. Geology and Geophysics, University of Utah, Frederick Albert Sutton Building, 115 S 1460 E, Salt Lake City, UT 84112-0102
| | - Kathleen A Ritterbush
- Dept. Geology and Geophysics, University of Utah, Frederick Albert Sutton Building, 115 S 1460 E, Salt Lake City, UT 84112-0102
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Oudot M, Neige P, Shir IB, Schmidt A, Strugnell JM, Plasseraud L, Broussard C, Hoffmann R, Lukeneder A, Marin F. The shell matrix and microstructure of the Ram’s Horn squid: Molecular and structural characterization. J Struct Biol 2020; 211:107507. [DOI: 10.1016/j.jsb.2020.107507] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/11/2022]
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