Micro- and nanostructures reflect the degree of diagenetic alteration in modern and fossil brachiopod shell calcite: A multi-analytical screening approach (CL, FE-SEM, AFM, EBSD)

Casella, Laura A.; Griesshaber, Erika; Roda, María Simonet; Ziegler, Andreas; Mavromatis, Vasileios; Henkel, Daniela; Laudien, Jürgen; Häussermann, Vreni; Neuser, Rolf D.; Angiolini, Lucia; Dietzel, Martin; Eisenhauer, Anton; Immenhauser, Adrian; Brand, Uwe; Schmahl, Wolfgang W.

doi:10.1016/j.palaeo.2018.03.011

Cited by 42 publications

(37 citation statements)

References 61 publications

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“…TEM analysis of shell RCK16 ( G. okensis ) (Figs 5–6) shows that the columnar layer is formed by nanoscopic, biocomposite mesocrystal calcite ( sensu Casella et al . ) that is built up by grains approximately co‐oriented and with the c‐axis lying on the plane of observation (the longitudinal section of the brachiopod shell; Fig. A), as observed in Recent taxa (Ye et al .…”

Section: Resultssupporting

confidence: 58%

“…There is no sign of calcite crystals with a rhombohedral morphology in the columnar layer, which argues against alteration (Casella et al . ). The columnar microstructure (Fig.…”

Section: Resultsmentioning

confidence: 97%

“…According to Casella et al . (, b), MUD values of well‐preserved brachiopods range between 40 and 80 (exceptionally being over 100); moderately to fairly well‐preserved brachiopod shells have MUD values between 20 and 40, and overprinted brachiopod shells have MUD values lower than 20. This suggests the Gigantoproductus shells used for geochemical analyses are indeed well preserved.…”

Section: Resultsmentioning

confidence: 99%

“…Skeletal carbonates, unlike non‐biogenic carbonates, contain organics and comparatively large amounts (up to 3% weight) of water (Gaffey ; Casella et al . , b) which form an intrinsic part of the carbonate skeleton incorporated during growth. Organic material (such as biopolymer membranes and network of fibrils) and water are intimately associated and are disseminated throughout skeletons in minute inter and intra‐crystalline cavities.…”

Section: Discussionmentioning

confidence: 99%

“…() and Casella et al . () in modern brachiopods and attributed to ‘intercrystalline organics’. Thus, at least some of the numerous inclusions revealed by TEM analysis are likely to be the remnants of occluded organic biopolymers within the columnar tertiary layer of calcite in the Gigantoproductus species shell.…”

Section: Discussionmentioning

confidence: 99%

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The giants of the phylum Brachiopoda: a matter of diet?

et al. 2019

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The species of the brachiopod Gigantoproductus are giants within the Palaeozoic sedentary benthos. This presents a dilemma as living brachiopods have low‐energy lifestyles. Although brachiopod metabolic rates were probably higher during the Palaeozoic than today, the massive size reached by species of Gigantoproductus is nevertheless unusual. By examining the diet of Gigantoproductus species from the Visean (Mississippian, Carboniferous) of Derbyshire (UK), we seek to understand the mechanisms that enabled those low‐metabolism brachiopod species to become giants. Were they suspension feeders, similar to all other brachiopods, or did endosymbiosis provide a lifestyle that allowed them to have higher metabolic rates and become giants? We suggest that the answer to this conundrum may be solved by the identification of the biogeochemical signatures of symbionts, through combined analyses of the carbon and nitrogen‐isotopic compositions of the occluded organic matrix within their calcite shells. The shells are formed of substructured columnar units that are remarkably long and a few hundreds of microns wide, deemed to be mostly pristine based on multiple analyses (petrography, cathodoluminescence (CL), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM)); they contain occluded organic fractions detected by TEM, nuclear magnetic resonance (NMR) and gas chromatography mass spectrometry (GC‐MS) analyses. We conclude that the gigantic size reached by the species of Gigantoproductus is probably the result of a mixotroph lifestyle, by which they could rely on the energy and nutrients derived both from photosymbiotic microbes and from filtered particulate food.

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Section: Resultssupporting

confidence: 58%

“…There is no sign of calcite crystals with a rhombohedral morphology in the columnar layer, which argues against alteration (Casella et al . ). The columnar microstructure (Fig.…”

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The giants of the phylum Brachiopoda: a matter of diet?

et al. 2019

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Comparative crystallography suggests maniraptoran theropod affinities for latest Cretaceous European ‘geckoid’ eggshell

Choi

Moreno‐Azanza

Csiki-Sava

et al. 2020

Papers in Palaeontology

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Thin fossil eggshell from Upper Cretaceous deposits of Europe, characterized by nodular ornamentation similar to modern gekkotan eggshell, has mostly been interpreted as gekkotan (=‘geckoid’) in origin. However, in some cases, as for the oogenus Pseudogeckoolithus, a theropod affinity has also been suggested. The true affinity of these fossil ‘geckoid’ eggshells has remained controversial due to the absence of analytical methods for identifying genuine gecko eggshell in the fossil record. In this study, we apply electron backscatter diffraction (EBSD) analysis to latest Cretaceous European ‘geckoid’ (including Pseudogeckoolithus) eggshell, in comparison with modern gekkotan and theropod (avian) eggshell. We found that Pseudogeckoolithus has a definite theropod eggshell‐like crystallographic configuration, in clear contrast to that seen in modern ‘gecko eggshells’. Furthermore, the crystallography of the nodular ornamentation in Pseudogeckoolithus is similar to that seen in megapode eggshell, but different from that of gecko eggshell, despite superficial morphological similarity. The remarkable morphological similarities between Pseudogeckoolithus and modern gecko eggshells are thus convergent, and the ‘gekkotan affinity’ hypothesis can be dismissed for Pseudogeckoolithus. This study provides a template for differentiating true gekkotan from dinosaurian eggshells in the fossil record. The potential functional significance of eggshell ornamentation, lost in most modern birds, requires further study, and experimental zoological approach may shed light on this issue. Finally, the present results suggest caution about the dangers of using potentially homoplastic eggshell characters in eggshell parataxonomy.

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The architecture of Recent brachiopod shells: diversity of biocrystal and biopolymer assemblages in rhynchonellide, terebratulide, thecideide and craniide shells

et al. 2021

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Biological hard tissues are a rich source of design concepts for the generation of advanced materials. They represent the most important library of information on the evolution of life and its environmental conditions. Organisms produce soft and hard tissues in a bottom-up process, a construction principle that is intrinsic to biologically secreted materials. This process emerged early on in the geological record, with the onset of biological mineralization. The phylum Brachiopoda is a marine animal group that has an excellent and continuous fossil record from the early Cambrian to the Recent. Throughout this time interval, the Brachiopoda secreted phosphate and carbonate shells and populated many and highly diverse marine habitats. This required great flexibility in the adaptation of soft and hard tissues to the different marine environments and living conditions. This review presents, juxtaposes and discusses the main modes of mineral and biopolymer organization in Recent, carbonate shell-producing, brachiopods. We describe shell tissue characteristics for taxa of the orders Rhynchonellida, Terebratulida, Thecideida and Craniida. We highlight modes of calcite and organic matrix assembly at the macro-, micro-, and nano-scales based on results obtained by Electron Backscatter Diffraction, Atomic Force Microscopy, Field Emission Scanning Electron Microscopy and Scanning Transmission Electron Microscopy. We show variation in composite hard tissue organization for taxa with different lifestyles, visualize nanometer-scale calcite assemblies for rhynchonellide and terebratulide fibers, highlight thecideide shell microstructure, texture and chemistry characteristics, and discuss the feasibility to use thecideide shells as archives of proxies for paleoenvironment and paleoclimate reconstructions.

show abstract

Micro- and nanostructures reflect the degree of diagenetic alteration in modern and fossil brachiopod shell calcite: A multi-analytical screening approach (CL, FE-SEM, AFM, EBSD)

Cited by 42 publications

References 61 publications

The giants of the phylum Brachiopoda: a matter of diet?

The giants of the phylum Brachiopoda: a matter of diet?

Comparative crystallography suggests maniraptoran theropod affinities for latest Cretaceous European ‘geckoid’ eggshell

The architecture of Recent brachiopod shells: diversity of biocrystal and biopolymer assemblages in rhynchonellide, terebratulide, thecideide and craniide shells

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