Microstructure, crystallography and diagenetic alteration in fossil ostrich eggshells from Upper Palaeolithic sites of Indian peninsular region

Jain, Sonal; Bajpai, Sunil; Kumar, Giriraj; Pruthi, Vikas

doi:10.1016/j.micron.2016.02.012

Cited by 11 publications

(6 citation statements)

References 13 publications

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“…Raman analyses confirm that the main components is calcite, and the narrow peaks are indicative of a well crystallized form, with the potential exception of the inner surface (spherulitic structures of the mammillary layer) and in agreement with EBSD diffraction results. EBSD data also confirms the calcitic composition of these eggshells and, in general, EBSD results are in agreement with those reported by Dalbeck and Cusack [62], and Jain et al [19] for fossil samples. The outer (prismatic) and spongy layers show high crystallinity and a strong preferred orientation of calcite crystals, whereas the mamillary layer presents two preferred crystallographic orientations of calcite related to differences in crystal sized and steps in the eggshell formation.…”

Section: Mineralogy-crystallographysupporting

confidence: 92%

“…Giant eggshells assigned to Struthioniformes are known from Africa [17] and Asia [18,19] and, in general, ostrich eggshells are valued as food resources and ostrich farms are present in Europe, North America, Asia, and Australia. Additionally, ostrich eggshells are abundant in archaeological sites and used for paleoenvironmental [20] and social network reconstructions [21,22], and for phylogenetic purposes [23].…”

Section: Introductionmentioning

confidence: 99%

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Integrated Information on the Structure and Composition of the Ostrich Eggshell (Struthio camelus)

et al. 2023

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Ostrich eggshells are excellent examples of avian biomineralization. Interest in these eggshells is focused on their potential as a food source, example of a biomaterial for medical and industrial applications, and the use of fossil remains for paleoenvironmental reconstructions. Due to this interest, there is some information about aspects of eggshell biomineralization, but it is scattered in different publications and is limited in scope about mineralogy-crystallography and/or composition. Here, we re-examine the biomineralization of the Struthio eggshells focusing on the structure, from macro- to nano-scales, crystallography, and composition of mineral and organic phases. Our results show that there is a very tight biomineralization control, from well-defined structures at nanoscale to precise crystallographic orientation of calcite crystals, in the formation of a biomineral that is unparalleled in other avian eggshells. Overall, this finding would explain the thickness and excellent mechanical properties of ostrich eggshells.

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Section: Mineralogy-crystallographysupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Integrated Information on the Structure and Composition of the Ostrich Eggshell (Struthio camelus)

et al. 2023

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“…For example, it can be used to discriminate diagenetic mineralization that could distort paleoclimate calculations [ 77 , 79 ]. Additionally, EBSD can also be employed to distinguish biologically induced and biologically controlled calcareous biomineralization in fossil organisms [ 80 ], to evaluate the degree of diagenetic alteration in modern and fossil brachiopod shell calcite [ 81 ], to study the crystallographic and ultrastructural features of dinosaur egg shells [ 82 ] and to investigate the microstructure, crystallography and diagenetic alteration in fossil ostrich egg shells [ 83 ].…”

Section: Non-destructive Chemical Imagingmentioning

confidence: 99%

Applications of chemical imaging techniques in paleontology

Pan

Tao

2018

National Science Review

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Chemical imaging techniques, based on a combination of microscopy and spectroscopy, are designed to analyse the composition and spatial distribution of heterogeneous chemical complexes within a sample. Over the last few decades, it has become an increasingly popular tool for characterizing trace elements, isotopic information and organic biomarkers (molecular biosignatures) found in fossils. Here, we introduce the analytical principle of each technique and the interpretation of the chemical signals, followed by a review of the main applications of these techniques in paleontology. We also demonstrate that each technique is associated with pros and cons, and the current limitations and obstacles associated with the use of each specific technique should be taken into account before being applied to fossil samples. Finally, we propose that, due to the rapid advances in the available technology and overall trends towards more multi-disciplinary studies in paleontology, chemical imaging techniques can be expected to have broader applications in paleontology in the near future.

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“…EDS indicates the eggshell has been dolomitized, so that it now contains a relatively high amount of magnesium (Supplementary Note 2). Dolomitization is not uncommon in fossil eggshells 16 . The eggshell layers are adjacent (closely adhering) in some regions (Fig.…”

Section: Resultsmentioning

confidence: 99%

An Early Cretaceous enantiornithine (Aves) preserving an unlaid egg and probable medullary bone

Bailleul¹,

O’Connor²,

Zhang³

et al. 2019

Nat Commun

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Understanding non-crown dinosaur reproduction is hindered by a paucity of directly associated adults with reproductive traces. Here we describe a new enantiornithine, Avimaia schweitzerae gen. et sp. nov., from the Lower Cretaceous Xiagou Formation with an unlaid egg two-dimensionally preserved within the abdominothoracic cavity. Ground-sections reveal abnormal eggshell proportions, and multiple eggshell layers best interpreted as a multi-layered egg resulting from prolonged oviductal retention. Fragments of the shell membrane and cuticle are both preserved. SEM reveals that the cuticle consists of nanostructures resembling those found in neornithine eggs adapted for infection-prone environments, which are hypothesized to represent the ancestral avian condition. The femur preserves small amounts of probable medullary bone, a tissue found today only in reproductively active female birds. To our knowledge, no other occurrence of Mesozoic medullary bone is associated with indications of reproductive activity, such as a preserved egg, making our identification unique, and strongly supported.

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Microstructure, crystallography and diagenetic alteration in fossil ostrich eggshells from Upper Palaeolithic sites of Indian peninsular region

Cited by 11 publications

References 13 publications

Integrated Information on the Structure and Composition of the Ostrich Eggshell (Struthio camelus)

Integrated Information on the Structure and Composition of the Ostrich Eggshell (Struthio camelus)

Applications of chemical imaging techniques in paleontology

An Early Cretaceous enantiornithine (Aves) preserving an unlaid egg and probable medullary bone

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