Evolution and biomineralization of pteropod shells.

• Published in: Journal of Structural Biology
• Main Authors: Ramos-Silva, Paula, Wall-Palmer, Deborah, Marlétaz, Ferdinand, Marin, Frédéric, Peijnenburg, Katja T.C.A.
• Other Authors: Plankton Diversity and Evolution, Naturalis Biodiversity Center Leiden, Centre for Life’s Origins and Evolution, Biogéosciences UMR 6282 Dijon (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Department of Freshwater and Marine Ecology, University of Amsterdam Amsterdam (UvA)-Institute for Biodiversity and Ecosystem Dynamics (IBED), Work funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreements No844345 project EPIC and No 746186 project POSEIDoN , by a Vidi grant (016.161351) from the Netherlands Organization for Scientific Research (NWO), and by additional support provided by internal funding from the Naturalis Biodiversity Center (Martin Fellowship), from the Malacological Society of London (Travel Award) and from recurrent annual funds of Biog´eosciences research unit (Dijon).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Aragonite curved fibres; Biominerals; Helical microstructure; Mollusc; Pteropods; Shells; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; [SDV.IB.BIO]Life Sciences [q-bio]/Bioengineering/Biomaterials; Ocean acidification
• Online Access: https://hal.archives-ouvertes.fr/hal-03379758; https://hal.archives-ouvertes.fr/hal-03379758/document; https://hal.archives-ouvertes.fr/hal-03379758/file/Pteropods-JSB%20Paula.pdf; https://doi.org/10.1016/j.jsb.2021.107779

12 pages International audience Shelled pteropods, known as sea butterflies, are a group of small gastropods that spend their entire lives swimming and drifting in the open ocean. They build thin shells of aragonite, a metastable polymorph of calcium carbonate. Pteropod shells have been shown to experience dissolution and reduced thickness with a decrease in pH and therefore represent valuable bioindicators to monitor the impacts of ocean acidification. Over the past decades, several studies have highlighted the striking diversity of shell microstructures in pteropods, with exceptional mechanical properties, but their evolution and future in acidified waters remains uncertain. Here, we revisit the body-of-work on pteropod biomineralization, focusing on shell microstructures and their evolution. The evolutionary history of pteropods was recently resolved, and thus it is timely to examine their shell microstructures in such context. We analyse new images of shells from fossils and recent species providing a comprehensive overview of their structural diversity. Pteropod shells are made of the crossed lamellar and prismatic microstructures common in molluscs, but also of curved nanofibers which are proposed to form a helical three-dimensional structure. Our analyses suggest that the curved fibres emerged before the split between coiled and uncoiled pteropods and that they form incomplete to multiple helical turns. The curved fibres are seen as an important trait in the adaptation to a planktonic lifestyle, giving maximum strength and flexibility to the pteropod thin and lightweight shells. Finally, we also elucidate on the candidate biomineralization genes underpinning the shell diversity in these important indicators of ocean health.