δ18O‐derived incubation temperatures of oviraptorosaur eggs |
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Authors: | Romain Amiot Xu Wang Shuo Wang Christophe Lécuyer Jean‐Michel Mazin Jinyou Mo Jean‐Pierre Flandrois François Fourel Xiaolin Wang Xing Xu Zhijun Zhang Zhonghe Zhou |
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Institution: | 1. CNRS UMR 5276 LGL‐TPE, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Villeurbanne Cedex, France;2. Key Laboratory of Cenozoic Geology & Environment, Institute of Geology & Geophysics, Chinese Academy of Sciences, Beijing, 100029, China;3. College of Life Sciences, Capital Normal University, Beijing, China;4. Institut Universitaire de France;5. Natural History Museum of Guangxi, Nanning, China;6. CNRS, UMR5558, Laboratoire de Biométrie et Biologie évolutive, Univ Lyon, Université Lyon 1, Villeurbanne, France;7. CNRS UMR 5023 LEHNA, Université Claude Bernard Lyon 1, Villeurbanne Cedex, France;8. Key Laboratory of Vertebrate Evolution & Human Origins, Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, Beijing, China;9. University of Chinese Academy of Sciences, Beijing, China;10. Department of Palaeontology, Geological Museum of China, Beijing, China |
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Abstract: | In order to determine the incubation temperature of eggs laid by non‐avian dinosaurs, we analysed the oxygen isotope compositions of both eggshell carbonate (δ18Oc) and embryo bone phosphate (δ18Op) from seven oviraptorosaur eggs with preserved in ovo embryo bones. These eggs come from the Upper Cretaceous Nanxiong Formation of Jiangxi Province, China. Oviraptorosaur theropods were selected because of their known brooding behaviour as evidenced by preserved adult specimens fossilized in brooding posture on their clutch. Incubation temperature of these embryos was estimated based on the following considerations: eggshell δ18Oc value reflects the oxygen isotope composition of egg water fluid; embryo bones precipitate from the same egg fluid; and oxygen isotope fractionation between phosphate and water is controlled by the egg temperature. A time‐dependent model predicting the δ18Op evolution of the embryo skeleton during incubation as a function of egg temperature was built, and measured δ18Oc and δ18Op values used as boundary conditions. According to the model outputs, oviraptorosaurs incubated their eggs within a 35–40°C range, similar to extant birds and compatible with the known active brooding behaviour of these theropod dinosaurs. Provided that both eggshell and embryo bones preserved their original oxygen isotope compositions, this method could be extended to investigate some reproductive traits of other extinct groups of oviparous amniotes. |
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Keywords: | oviraptorosaur embryo eggshell incubation temperature oxygen isotopes China |
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