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Re: [dinosaur] Oviraptorosaur eggs.incubation temperatures from oxygen isotopes



Possibly of interest, this study also cites a recent (2016) paper to my knowledge not previously mentioned on this list.

S.A. Lee (2016)
Incubation times of dinosaur eggs via embryonic metabolism
Physical Review E 94: 022402
DOI: 10.1103/PhysRevE.94.022402
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.94.022402

The incubation times for the eggs of 21 dinosaurs are determined from an estimate of their embyronic metabolic rate and the mass of the hatchlings via a mass growth model based on conservation of energy. Embryos in extant birds and crocodiles are studied in order to determine the best model for embryonic metabolism and growth. These results are used to develop a theoretical model that predicts the incubation times of an egg. This model is applied to dinosaur eggs and provides a unique window into dinosaur reproduction. The dinosaurs studied come from both Saurischia and Ornithischia. The incubation times vary from about 28 days for Archaeopteryx lithographica to about 76 days for Alamosaurus sanjuanensis.

On Wed, Jun 28, 2017 at 4:27 PM, Ben Creisler <bcreisler@gmail.com> wrote:

Ben Creisler
bcreisler@gmail.com


A new paper:


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  (2017)
δ18O-derived incubation temperatures of oviraptorosaur eggs.
Palaeontology (advance online publication)
DOI: 10.1111/pala.12311 



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.