Supplementary data from: Reassessment of body temperature and thermoregulation strategies in Mesozoic marine reptiles
Data files
Dec 16, 2024 version files 124.64 KB
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README.md
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TableS1_Full_isotope_values.xlsx
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TableS2_RMM_news_TB.xlsx
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TableS3_Raman_parameters.xlsx
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Abstract
Ichthyosauria, Plesiosauria and Metriorhynchidae were apex predators in Mesozoic oceanic trophic networks. Previous stable oxygen isotope studies suggested that several taxa belonging to these groups were endothermic and for some of them homeothermic organisms. However, these conclusions remain contentious owing to the associated uncertainties regarding the δ18O value and oxygen isotope fractionation relative to environmental sea water. Here, we present new bioapatite phosphate δ18O values (δ18Op) of Ichthyosauria, Plesiosauria and Metriorhynchidae (Middle Jurassic to Early Cretaceous) recovered from mid- to high-paleolatitudes to better constrain their thermophysiology and investigate the presence of regional heterothermies. The intra-skeletal δ18Op variability failed to reveal distinct heterothermic patterns within any of the specimens, indicating either intra-body temperature homogeneity or an overriding diagenetic overprint of the original biological δ18Op bone record. Body temperature estimates have then been reassessed from new and published δ18Op values of well-preserved isolated teeth, recently revised Mesozoic latitudinal δ18O oceanic gradient and 18O-enrichment factor of fully aquatic air-breathing vertebrates. Our results confirm that Ichthyosauria were homeothermic endotherms (31°C to 41°C), while Plesiosauria were likely poikilothermic endotherms (27°C to 34°C). The new body temperature estimates of the Metriorhynchidae (25°C to 32°C) closely follow ambient temperatures and point to poikilothermic strategy with no or little endothermic abilities. These results improve our understanding of Mesozoic marine reptile thermoregulation and indicate that due to their limited body temperature variations, the δ18Op values from Ichthyosauria fossil remains could be used as valuable archives of Mesozoic oceans δ18Osw values that may help improve palaeoenvironmental and palaeoclimatic reconstructions.
README: Supplementary data: Reassessment of body temperature and thermoregulation strategies in Mesozoic marine reptiles
https://doi.org/10.5061/dryad.8gtht76zf
Description of the data and file structure
Please find here the supplementary data of the manuscript. It includes detailed isotope data, Raman spectroscopy data, body temperature estimates, and some additional figures.
Supplementary Table 1: Oxygen and carbon isotope values (δ18Op, δ18Oc, δ13Cc), along with CO₃²⁻ and P₂O₅ content (wt%) of bioapatite extracted from the bones and teeth of Ichthyosauria, Plesiosauria, and Metriorhynchidae. Oxygen isotope values in bold represent data excluded from the dataset due to mineralogical alteration, while values in italics indicate data removed due to carbonate content exceeding 13.4 wt%.
Supplementary Table 2: Environmental sea water temperature and Ichthyosauria, Plesiosauria and Metriorhynchidae new body temperatures using the equation of Lécuyer et al. (2013) and considering the latitudinal gradient of δ18Osw values of Alberti et al. (2020) and an 18O-enrichment of body water relative to environmental water of 0.8% for Mesozoic marine reptiles (Séon et al. 2023). The table compiles oxygen isotope data for the phosphate bioapatite from the teeth of these groups, organized by their geographical locations. Difference between old (Anderson et al. 1994, Bernard et al. 2010, Séon et al. 2020) and new body temperature estimates for Ichthyosauria, Plesiosauria and Metriorhynchidae according to palaeolatitude.
Supplementary Table 3: Raman spectral parameters, including the position (ν₁- PO₄³⁻) and full width at half maximum (FWHM) of the ν₁-PO₄³⁻ peak, for bone and teeth samples of Ichthyosauria, Plesiosauria, and Metriorhynchidae.
Supplementary information 1: Isotope-based body temperature calculations.
Supplementary Figure 1: Boxplots showing the P2O5 content expressed in weight percentage of apatite (wt%) distribution of Mesozoic marine reptile bones and teeth along the fossil deposits (A.) and the specimens (B.). Outliers are plotted as white circles. The horizontal bars in the boxes correspond to the medians and the whiskers to the minimum and maximum values.
Supplementary Figure 2: Boxplots showing the P2O5 content (wt%) distribution of bones sets for the specimens of Ichthyosauria (A. Ichthyosauria indet, B. Keilhauia sp., C. Palvennia hoybergeti), Plesiosauria (D. Colymbosaurus svalbardensis and E. Cryptoclididae indet., F. Elasmosauridae indet.,) and Metriorhynchus aff. superciliosus (G.). Asterisks indicate the significance of the observed differences between pair of groups: * for p-value < 0.05, ** for p-value < 0.01 and *** for p-value < 0.001. Outliers are plotted as white circles. The horizontal bars in the boxes correspond to the medians and the whiskers to the minimum and maximum values.
Supplementary Figure 3: Values of δ18Op (‰, V-SMOW) as a function of P2O5 content (wt%) according to mineralized elements (bones and teeth) in Ichthyosauria (A.) and Plesiosauria (B.).
Supplementary Figure 4: δ18Oc values (‰, V-SMOW) versus carbonate content of the bones and tooth from the specimen of Ichthyosauria indet.
Supplementary Figure 5: Comparison between previous body temperature in white (Bernard et al. 2010; Séon et al. 2020) and new body temperature estimates in black for Ichthyosauria, Plesiosauria and Metriorhynchidae according to palaeolatitude.