Synchrotron radiation in palaeontological investigations: Examples from Brazilian fossils and its potential to South American palaeontology

Prado, Gustavo; Arthuzzi, Jorge C.L.; Osés, Gabriel Ladeira; Callefo, Flavia; Maldanis, Lara; Sucerquia, Paula Andrea; Becker-Kerber, Bruno; Romero, Guilherme R.; Quiroz-Valle, Francy Roxana; Galante, Douglas

doi:10.1016/j.jsames.2020.102973

Cited by 8 publications

(6 citation statements)

References 110 publications

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“…2019; Prado et al . 2021). Although the application of these techniques has been used with great success in clarifying the identity of unknown or ambiguous characters in early vertebrates, they have not been widely used when considering Lasanius specimens (Sansom et al .…”

Section: Figmentioning

confidence: 99%

Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

et al. 2023

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The fossil record of non-biomineralizing, softbodied taxa is our only direct evidence of the early history of vertebrates. A robust reconstruction of the affinities of these taxa is critical to unlocking vertebrate origins and understanding the evolution of skeletal tissues, but these taxa invariably have unstable and poorly supported phylogenetic positions. At the cusp between mineralized bony vertebrates and entirely soft-bodied vertebrates is the enigmatic Lasanius, a purported anaspid from the Silurian of Scotland. Interpretations of its affinity and significance are conflicted, principally because of its poorly understood anatomy due to taphonomic distortion and loss of soft-tissues. Here we use an array of modern techniques to reassess the anatomy of Lasanius via a comprehensive study of 229 complete and partial specimens. A new reconstruction clarifies the identity and position of preserved features, including paired sensory organs, a notochord, and digestive tract, supporting the vertebrate affinities of this genus. SEM-EDS trace element mapping suggests a bone-like composition of mineralized parts, but finds no evidence for mineralized dermal armour. Phylogenetic analysis recovers Lasanius as an early stem-cyclostome, and subsequent analysis supports the rejection of alternative placements (such as stemgnathostome). We highlight that while distinguishing between the early cyclostome and gnathostome condition is problematic, increasing confidence in the anatomy of key taxa, such as Lasanius, is vital for increased stability throughout the early vertebrate tree.

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Section: Figmentioning

confidence: 99%

Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

et al. 2023

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“…This feedback between measure and questioning is not only a question of instruments and skills; heritage objects play an essential role in the translation of concepts at the interdisciplinary frontier , (Figure ). We believe that the development of interdisciplinary platforms or teams dedicated to ancient and heritage materials that couple fundamental methodological research and application − is a favorable factor in encouraging such innovation and that the approach of identifying the intrinsic specificities of the materials studied plays a central role here, even leading to a more precise definition of “ancient material” as a relational concept.…”

Section: Discussionmentioning

confidence: 99%

Deciphering the Chemistry of Cultural Heritage: Targeting Material Properties by Coupling Spectral Imaging with Image Analysis

et al. 2021

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“…The presence of microcracks in the insect cuticles of the Crato Formation has been frequently reported (Delgado et al 2014;Barling et al 2015Barling et al , 2020Osés et al 2016;Bezerra et al 2020Bezerra et al , 2021Dias & Carvalho, 2020Prado et al 2021). Crato insects with iron-oxide overgrowths show intricate zones of microcracks associated with compact cuticular surfaces without individualized 914 FI Bezerra et al…”

Section: B Scanning Electron Micrograph Analysismentioning

confidence: 94%

Effects of chemical weathering on the exceptional preservation of mineralized insects from the Crato Formation, Cretaceous of Brazil: implications for late diagenesis of fine-grained Lagerstätten deposits

Bezerra

Silva²,

Agressot³

et al. 2023

Geol. Mag.

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Many studies have improved our understanding of the mode of preservation at the Crato fossil Lagerstätte. The high degree of preservation of the Crato mineralized insects is thought to be a consequence of the diffusion of ions through carcasses and envelopment by bacteria that, in turn, created microenvironmental conditions that led to mineralization, mainly pyritization. Pyritized insects have been oxidized by in situ weathering to more stable oxide/hydroxy minerals during Quaternary time. This transformation is essential to maintain the palaeontological information acquired during microbially induced pyritization in an oxidizing atmosphere. However, intense weathering can diminish or obscure the morphological fidelity, and little attention has been paid to the post-diagenetic processes experienced by these fossils. Here, we aim to determine the degree of alteration undergone by Crato pyritized insects using the following combination of analytical tools: scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared and Raman spectroscopy. Our results show that well-preserved insects are preferentially replaced by haematite and poorly preserved fossils are replaced by goethite. In addition, we recorded three types of post-diagenetic alteration: insects with iron-oxide overgrowths; insects associated with black coatings, sometimes with the formation of dendrites; and insects preserved as an impression, where only the outline of the body remains. All of these alterations have the potential to distort or tarnish palaeontological information. Here, we measured the effects of such telodiagenetic alterations at macro and micro scales. Therefore, this taphonomic approach has wide applicability wherever fine-grained deposits bearing mineralized insects are found.

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Synchrotron radiation in palaeontological investigations: Examples from Brazilian fossils and its potential to South American palaeontology

Cited by 8 publications

References 110 publications

Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

Lasanius, an exceptionally preserved Silurian jawless fish from Scotland

Deciphering the Chemistry of Cultural Heritage: Targeting Material Properties by Coupling Spectral Imaging with Image Analysis

Effects of chemical weathering on the exceptional preservation of mineralized insects from the Crato Formation, Cretaceous of Brazil: implications for late diagenesis of fine-grained Lagerstätten deposits

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