An Early Jurassic soft eggshell provides insights into the evolutionary history of dinosaur eggs
Data files
Jul 06, 2026 version files 139.01 MB
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Raman_mapping_(sites_1–4__6__8–10)_and_spot_(sites_5__7)_spectroscopic_datasets_were_acquired_at_the_...labelled_with_bold_numbers_in_LFGT-0400-07_LFGT-0400-01_LFGT-0400-09_for_Supplementary_Figure_45.zip
13.77 MB
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Raman_spot_spectroscopic_dataset_was_acquired_at_the_positions_labelled_with_numbers_in_LFGT-0400-06_for_Figure_4a.zip
623.77 KB
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README.md
5.06 KB
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The_3D_STL_files_for_Mutabilisoolithus_dawaensis_(LFGT-0400)_and_two_embryonic_skeleton_masses_(LFGT0401_and_LFGT0402).zip
124.61 MB
Abstract
Early eggshell fossils offer invaluable insights into evolutionary innovations in over 300 million years of amniote egg history. However, the incompleteness of the dinosaur eggshell fossil record hinders ancestral state reconstruction and leads to uncertainty about whether the first dinosaur egg was soft-shelled, semi-rigid-shelled, or rigid-shelled. Herein, we present a fossilized soft eggshell (Mutabilisoolithus dawaensis) from an Early Jurassic basal sauropodomorph. We find that M. dawaensis has a soft plastic-like deformation, a thick cuticle, a thin calcareous layer formed by non-interlocking shell units, and a significantly thick shell membrane. Its shell membrane is similar to that of avian eggs in structure, diameter, and arrangement of the fibers, as well as in the distinctions among outer, inner, and limiting membrane layers, but it is much thicker than that of avian eggs. In dinosaurian egg evolutionary history, M. dawaensis provides evidence of early Jurassic soft-shelled eggs, may represent the earliest stage of biomineralization, and bridges the gap between non-biomineralized membranous soft eggshells and biomineralized semi-rigid eggshells.
Dataset DOI: 10.5061/dryad.7pvmcvf5m
Description of the data and file structure
We used high-resolution microcomputed tomography, three-dimensional reconstruction, slice scanning (under plane-polarized light (ppl), cross-polarized light (xpl), and reflected light (rl)), cold cathodoluminescence (CL), electron back-scattered diffraction analysis (EBSD), energy-dispersive X-ray spectroscopy (EDS), electron probe microanalysis (EPMA), Raman analysis, and scanning electron microscope analysis (SEM) to present a newly discovered known fosslized eggshell (Mutabilsoolthus dawaensis, 195 Mya) of an Early Jurassic basal sauropodomorph.
The relevant STL files and Raman spectroscopic datasets have been uploaded here.
Files and variables
File:
The_3D_STL_files_for_Mutabilisoolithus_dawaensis_(LFGT-0400)and_two_embryonic_skeleton_masses(LFGT0401_and_LFGT0402).zip
Description: The material was scanned using a Phoenix v|tome|x m system (Germany) at Yinghua Testing (Shanghai) Co., Ltd, under conditions of 200 kV and 200 µA, with a resolution of 28.5 μm and 1400 projections. Subsequently, the artifact and beam-hardening effects were mitigated before the reconstruction of the digital 3D model. Volume Graphics Studio Max was applied to analyze and process the reconstructed 3D model data. The CT data analysis software, Drishti 2.7, was utilized for the analyses at Chengdu Eleven Monkeys Technology Co., Ltd. to reconstruct and evaluate the generated digital 3D model. Subsequently, the scanned data were imported into the data processing workstation and 3D reconstruction software (Mimics 16) to visualize various parts of the fossil material. The resulting reconstructed model was rendered and produced as STL (Stereolithography) files.
File: Raman_spot_spectroscopic_dataset_was_acquired_at_the_positions_labelled_with_numbers_in_LFGT-0400-06_for_Figure_4a.zip
Description: Spot Raman analyses (Fig. 4a) were conducted by using an entirely integrated confocal Raman microscope (LabRAM HR Evolution, France) at the Hebei Key Laboratory of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University. The instrument was calibrated using a silicon wafer. The excitation for both Raman spot and mapping analyses was achieved using a 532 nm solid-state laser. The grating used for Raman testing was 1800 g/mm, with a 5 μm incident beam and an excitation time of 3 s (Fig. 4a), employing a laser combined with a 100-fold objective lens. The spectroscopic datasets for spot analyses were obtained in the range of 100–2000 cm−1 (Fig. 4a).
File:
Raman_mapping_(sites_1–4__6__8–10)and_spot(sites_5__7)_spectroscopic_datasets_were_acquired_at_the_positions_labelled_with_bold_numbers_in_LFGT-0400-07_LFGT-0400-01_LFGT-0400-09_for_Supplementary_Figure_45.zip
Description: Spot (Supplementary Fig. 45: sites 5 and 7) and mapping (Supplementary Fig. 45: sites 1–4, 6, and 8–10) Raman analyses were conducted by using an entirely integrated confocal Raman microscope (LabRAM HR Evolution, France) at the Hebei Key Laboratory of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University. The instrument was calibrated using a silicon wafer. The excitation for both Raman spot and mapping analyses was achieved using a 532 nm solid-state laser. The grating used for Raman testing was 1800 g/mm, with a 5 μm incident beam and an excitation time of 5 s (Supplementary Fig. 45) by employing a laser combined with a 100-fold objective lens. The spectroscopic datasets for spot analyses were obtained in the range of 100–2000 cm−1 (Supplementary Fig. 45: site 5) or 100 to 4000 cm−1 (Supplementary Fig. 45: site 7). For the Raman spectroscopic mapping analyses, the spectroscopic datasets were obtained within the range of 100–2000 cm−1 (Supplementary Fig. 45: sites 1–4, 6, and 8–10).
Code/software
File: The_3D_STL_files_for_Mutabilisoolithus_dawaensis_(LFGT-0400)and_two_embryonic_skeleton_masses(LFGT0401_and_LFGT0402).zip
Description: Paint 3D (https://paint-3d.com/).
File: Raman_spot_spectroscopic_dataset_was_acquired_at_the_positions_labelled_with_numbers_in_LFGT-0400-06_for_Figure_4a.zip
Description: Spectragryph 1.2 (https://www.effemm2.de/spectragryph/) or LabSpec (the software bundled with the HORIBA Raman spectrometer for authorized use).
File: Raman_mapping_(sites_1–4__6__8–10)and_spot(sites_5__7)_spectroscopic_datasets_were_acquired_at_the_positions_labelled_with_bold_numbers_in_LFGT-0400-07_LFGT-0400-01_LFGT-0400-09_for_Supplementary_Figure_45.zip
Description: RamApp (https://ramapp.io/) or LabSpec (the software bundled with the HORIBA Raman spectrometer for authorized use).